MWell User Manual
Contents
1. c d Vertical hydraulic resistance of a semi impervious layer i e aquitard c D k kp m d Transmissivity of an aquifer n Porosity Eoed kN m Oedometer stiffness G kN m Shear modulus Cy m d Consolidation coefficient Kp kN m Bulk modulus of the drained soil skeleton Ries m d Darcy permeability Sheet Piling p m d Reciprocal hydraulic joint resistance R d Sheet piling flow resistance b m Sheet piling width Pore fluid K kN m Bulk modulus of the pore fluid Yf kN m3 Unit weight of the pore fluid Getting Help From the Help menu choose the Manual option to open the User Manual of MWell in PDF format Here help on a specific topic can be found by entering a specific word in the Find field of the PDF reader Getting Support Deltares Systems tools are supported by Deltares A group of 70 people in software develop ment ensures continuous research and development Support is provided by the developers and if necessary by the appropriate Deltares experts These experts can provide consultancy backup as well If problems are encountered the first step should be to consult the online Support at www deltares com in menu Software Different information about the program can be found on the left hand side of the window Figure 1 2 In Support Freguentely asked questions are listed the most frequently asked technical guestions and their answers In Support Known issues are listed2. Besides the familiar Windows options for opening and saving files the File menu contains a number of options specific to MWell o Copy Active Window to Clipboard Use this option to copy the contents of the active window to the Windows clipboard so that they can be pasted into another application The contents will be pasted in either text format or Windows Meta File format o Export Active Window Use this option to export the contents of the active window as a Windows Meta File wmf a Drawing Exchange File dxf or a text file txt o Export Report This option allows the report to be exported in a different format such as paf or rtf o Page Setup This option allows definition of the way MWell plots and reports are to be printed The printer paper size orientation and margins can be defined as well as whether and where axes are required for plots Click Autofit to get MWell to choose the best fit for the page o Print Preview Active Window This option will display a print preview of the current contents of the Input Diagram or Results window o Print Active Window This option printsthe current contents of the Input Diagram or Results window o Print Preview Report This option will display a print preview of the calculation report o Print Report This option printsthe calculation report 3 2 Tools menu 3 2 1 Program Options On the menu bar click Tools and then choose Options to open the corresponding input win
3. ap Deltares 27 of 49 MWell User Manual 28 of 49 Deltares 5 Calculations 5 1 As soon as proper input is available a calculation may be performed If not a message appears referring an error file for trouble shooting Calculation focuses on two important characteristics drawdown and settlement Calculation results may be approached in two different ways depending on the reguired visualization o Forthe purpose of making contour plots results in all nodes of the mesh at pre selected times specified in a list o Forthe purpose of making time history charts results in pre selected coordinate points specified in a list at regular time intervals The choice for contour plot and or time history chart is made in calculation type During calculation the progress is visualized by progress bars Calculation input Monitoring Points To follow the propagation of drawdown and settlement in time selected points can be intro duced as if these were piezometers for drawdown observation in practice For the monitoring points at the user defined X and Z coordinates time history calculations in MWell will be per formed at regular time intervals Time history results are calculated at these points for all aguifers W Monitoring Points xj Se x co ordinate Z co ordinate 5 m m pla 0 000 0 000 sx 2 40 000 0 000 3 40 000 15 000 4 40 000 20 000 5 40 000 50 000 6 40 000
4. load Refer to the Background section section 7 8 for an estimation of this parameter Deltares 23 of 49 MWell User Manual Specific Data for the specific storage can not be entered because the value is cal storage culated by the program from other parameter values The value is shown but the input box is blocked indicated by a grey color Refer to the Back ground section section 7 7 for the determination of this parameter Color Name Itis optional to enter user specified colors and names for the layers in each cluster Those data s are used in the Stratification window Porosity Enter the porosity of the layer To select proper values for the other input parameters the user should have a basic knowledge of hydro geology For basic additional information the user is referred to chapter 7 4 2 2 Discharge Wells Wells have a filter over the complete height of one aguifer A discharge positive value or infiltration negative value can be given as a fixed pumped guantity which is switched on at a specified time and switched off later The reguired data are entered via edit boxes Wells are distinguished by number In the layout window this number is labeled to the wells The position of the wells may be edited in the dialog box or by dragging The filter position is connected to the cluster number Discharge Wells 7 T T Je Discharge Switch On Switch Off Diameter Filter in
5. 7 2 21 Menubar lt lt kA ILL 8 2 2 2 lconbar GOB coo 9 2 2 3 Input Diagram window m BY o 9 2 2 4 Stratification window profile with soil clusters 11 2 25 Mobic eee ks ak k WM ee da sua KU 12 2 26 Statusbar Oho jj lk 12 23 Files Mia 988IA 22 25 05 12 3 General 15 3 1 Filemenu lt JOIN K kka 15 3 2 Tools menu s s im MI a ee tbe ee we ee 15 3 2 1 Program Optio MB 15 3 3 Helpmenu BY BM A o 18 4 Input 19 4 1 Project menu Wa BO KL K NII kanne 19 4 1 1 Model MBA K IIN es 19 4 1 2 LosationMap b LKK K k ka A 19 4 1 3 lt Project Properties ke 20 4 149 View Input RIB lt lt lt 1 es 23 4 2 Geometry Menu e 23 4 2 WWBbrofile W KA ee 23 4 2 2 Discharge Wells e 24 4 2 3 Sheet Pilings e 25 424 Mesh W lt k a ee ee ae es 26 4 3 Water Menu LL 27 43 1 Water Properes lt lt discordia De Oe 27 5 Calculations 29 51 DAN IAP L lt lt vesi E 84 Re Pa ag 29 5 1 1 Monitoring Points s i ai 254 ee ad Bk bee a 29 5 1 2 Gontauring mee 62 ca fe eee ha aa Kk Ae ee PAS 29 5 13 Monitoring 1168 lt lt doaa pada bo koh OR d a 30 5 2 Start Calculation a io s e moi a ica E o o 31 5o HUOMIO o a d ior Bae ee kN e PR A KuPS NW Ae ee BD 8 32 od Emr rMessag s ik aaora H aa p ke ee te oe ee dn 32 6 View Results 33 Deltares iii MWell User Manual Ol AR 33 Ge Qomour PIO is
6. 7 85E 03 Color Height Resistance Transmissivity Stiffness Porosity Identifier course sand 8388800 1 50 2500 00 1 47E 03 12640511 3 00 500 00 3 92E 03 Color Height Resistance Transmissivity Stiffness Porosity Identifier stiff clay gravel 12582912 0 50 20 00 27E 0Z 8438015 2 00 1500 00 7 8SE 03 Color Height Resistance Transmissivity Stiffness Porosity LIST number of items Identifier Filter cluster position Filter location X Filter location Z Discharge SwitchOn time SwitchOff time Diameter 50 000 500 000 0 000 Identifier Filter cluster position Filter location X 50 000 500 000 30 000 120 000 Filter location Z Discharge SwitchOn time SwitchOff time Diameter Figure 6 1 Report window short report The long version contains the following program name and version update company name license and data and time of run ning the program echo of the input 34 of 49 Deltares 6 2 View Results the points of time of calculation if contour plot is applied o the X Z coordinates of calculation if time history plot is applied o the mesh data and the change in piezometric level in the aquifers of all strata at each point of time if contour plot is applied o the change in piezometric level in the aguifers of all strata at specified X Z coordinates in a range of time if time history charts is applied Contour Plot A dumpfi
7. and results in e g appendix pages can be changed 6 3 Time History Chart Time History Chart 0 xj Edit 2 5 5 ol i i W i Cluster D 2 H H H H 1 A a e 9s 3 Tools 2 iQ Monitoring 10 X Point 7 X 40 00 m Z 58 00 m E TN AT U KP NN 5 s cc AA AAA e AA idea saa5 00 a n a saan sen sk osaa su0ssa sa eta AAA A An slan assua saussaat i T T t 20 50 100 200 500 1000 Time days Figure 6 4 Time History Chart window WE Time history charts for Drawdown and Settlement and for all monitoring points are available An up down button allows paging through the charts After clicking the Print icon the plot will be printed in a frame The settings of the frame can be changed by clicking the icon of Page setup The axis of the chart can not be edited by the user By mouse clicking on the nodes in the graphs the calculated values will be shown temporarily Deltares 37 of 49 MWell User Manual 38 of 49 Deltares 7 Theory of groundwater flow 7 1 MWell determines transient flow and settlements caused by well extraction of groundwater in a multi layered system of permeable aguifers with interjacent aguitards Basic Eguations MWell uses equation 7 1 for stress equilibrium and equation 7 2 for mass conservation in combination with Darcy s Law Stress Equilibrium do Od do De y 0 2 Eoed 7 1 an o Ot o
8. dow In this window the user can optionally define their own preferences for some of the program s default values Deltares 15 of 49 MWell User Manual View Hi Program Options xj W General Locations Modules Y Toolbar JY Status bar FF Title panel Figure 3 1 Program Options window View tab Toolbar Status bar Mark the relevant checkbox to display the tool bar and or status bar each time MWell is started Title panel Mark this checkbox to display the project titles as entered on the dentification tab in a panel at the bottom of the Input Diagram window General M4 Program Options xj i Locations Modules View f Startup with Save on Calculation No project Always Save Last used project C Always Save As New project Use Enter key to Press the default button Windows style Set focus to the next control DOS style Figure 3 2 Program Options window General tab Startup with Click one of these toggle buttons to determine how a project should be initi ated each time MWell is started No project Use the buttons in the toolbar or the options in the File menu to open an existing project or to start a new one Last used project The last project to be worked on is opened automatically New project A new project is created comprising a sheet pile wall with a dummy soil layer on both sides NOTE The Startup with option is ignored when MW
9. for different soil types 45 Average values for the reciprocal hydraulic joint resistance followed from tests performed for Arcelor e 45 Typical values of porosity for different soil types L 46 vii MWell User Manual viii Deltares 1 1 1 2 General Information Preface MWell is a tool to facilitate fast and flexible calculations of the drawdown and settlement due to well pumping in a set of permeable aquifers and less permeable aquitards The settlement calculation also involves the compression of the aquitards The MWell program determines the transient flow field in a multilayered drainage system The layers consist of intermittent aquifers and aquitards In the permeable aquifers wells may be placed to pump up water which flows mainly horizontally to the filters The semi permeable aquitards cause the water to leak in between the aquifers in a more or less vertical fashion An elegant and powerful method is available to determine the flow in the layered geometry the technique of matrix diagonalisation all layers have a constant thickness and extend indefinitely every separate layer is homogeneous the flow in the aguifers is mainly horizontal determined by transmissivity and storage the flow in the aguitards is mainly vertical controlled by resistance and storage every well has a filter over the complete height of one aquifer 000000 The inverse Laplace Transformation of the solution is performed by a
10. pile wall will slow down the calculation process The user is advised to choose these distances with care The amount of sheet piling sections affects the calculation time of the program From each end point or connection the minimum distance for segment length is used in the program for partitioning of segments The user is advised to model the lay out of the sheet piling as schematized as possible Since the drawdown has a discontinuity at the sheet piles contouring needed special care Contouring is performed by the program in a system of regular triangles At the position of the sheet piles these triangles are split considering the position of the sheet piles In this way a perfectly sharp interface is obtained as is shown in Figure 7 2 lola Edit Cluster N a 8 3 Drawdown m T o 100 200 300 Time days Figure 7 2 Time History Chart window 7 3 3 Use of sheet pilings in MWell A sheet piling consists of a series of sheet piles One segment of a sheet pile wall is specified by consecutive begin and end co ordinates see Figure 7 3 The sheet pile wall is hydrauli cally closed from a theoretical viewpoint if the last end point coincides with the first begin point In that case a location or building pit is completely surrounded with sheet piles The issue of closed needs some explanation A geometrically closed sheet piling may be composed of one single segment with one she
11. position in the geometry by the limits in the X Z coordinate plane of Left X Right X Top Z Bottom Z m Copy co ordinates to If desired it is possible to take the picture limits also as the limits mesh on pressing OK of the calculation mesh by checking this option in the dialog box 4 1 3 Project Properties On the menu bar click Project and then choose Properties to open the input window The Project Properties window contains several tabs which allow the settings for the current project to be changed Project Properties Identification Use the Identification tab to specify the project identification data Identification Project Properties E x Identification Input View Contour Plot Options Tite Enter here a description ofthe project 0 Title 2 NIITIT Title 3 NINNI Date 11 17 2009 IV Use current date Drawn by Das Project ID Mwl project Annex ID I Save as default Cancel Figure 4 3 Project Properties window Identification tab Titles Use Title 1 to give the project a unique easily recognizable name Title 2 and Title 3 can be added to indicate specific char acteristics of the calculation The three titles will be included on printed output 20 of 49 Deltares Input Date Drawn by Project ID Annex ID The date entered here will be used on printouts and graphic plots for this project Either mark the Use current date checkbox to automatically use the
12. shown in the stratification window The individual aquitards and aquifers can be named too To distinguish the layers a color may be chosen from a pre selected set The required data are entered via edit boxes The bottom of the geometry is assumed to be impervious course sand Figure 2 6 Stratification window N Profile properties ES Click this button to open the Profile window section 4 2 1 and edit modify the soil profile Zoom in 24 Click this button to enlarge the drawing and then click on the drawing on the part which is to be at the centre of the new image Zoom out E Click this button and then click on the drawing to reduce the drawing NN Zoom limits pal Click this button to display the complete drawing Deltares 11 of 49 MWell User Manual Print al Click this button to print the soil stratification 2 2 5 Info bar E This bar situated at the bottom of the Input Diagram window displays the co ordinates of the current position of the cursor and the distance between two points when the icon Measure the distance between two points is selected from the Edit panel All programs by Delft GeoSystems like MWell take the Y coordinate for the vertical direction As a result the position in the horizontal plane is defined by the X and Z co ordinates 2 2 6 Status bar This bar situated at the bottom of the main window displays a description of the selected icon of
13. the icon bar section 2 2 2 or of the Input Diagram window section 2 2 3 2 3 Files wec Mesh file ASCII Contains the mesh data wed Dump file ASCII Contains calculation results used in the short report sec tion 6 1 wedx Dump file ASCII Contains calculation results used in the long report sec tion 6 1 weh Dump file ASCII Used to visualize the drawdown and settlements in the Time History Chart window of the Results menu section 6 3 wei Input file ASCII Contains the input with the problem definition After inter active generation this file can be re used in subsequent MWell analyses weo Output file ASCII After a calculation has been performed all output is writ ten to this file wes Setting file ASCII Working file with settings data This file doesn t contain any information that is relevant for the calculation but only settings that apply to the representation of the data such as the grid size 12 of 49 Deltares Tutorial No tutorial available yet As example files open one of the demo files in the installation directory of MWell Deltares 13 of 49 MWell User Manual 14 of 49 Deltares 3 General This chapter contains a detailed description of the available menu options for inputting data for a project and for calculating and viewing the results The examples in the tutorial section provide a convenient starting point for familiarization with the program 3 1 File menu
14. the issues of the program In Release notes D Geo Pipeline are listed the differences between an old and a new version 4 of 49 Deltares General Information Figure 1 2 Software menu of the Deltares Systems website www deltares com If the solution cannot be found there then the problem description can be e mailed preferred or faxed to the Deltares Systems support team When sending a problem description please add a full description of the working environment To do this conveniently Open the program If possible open a project that can illustrate the question Choose the Support option in the Help menu The System Info tab contains all relevant information about the system and the DSeries software The Problem Description tab enables a description of the problem encountered to be added Deltares Delft GeoSystems Rotterdamseweg 185 Phone 31 88 335 79 09 YA P O Box 69 Fax 31 88 335 81 11 Cj NL 2600 4B Delft E mail support delftgeosystems nl System Info Problem Description Please explain your issue here Send Print oa Figure 1 3 Support window Problem Description tab o After clicking on the Send button the Send Support E Mail window opens allowing sending current file as an attachment Marked or not the Attach current file to mail checkbox and click OK to send it Deltares 5 of 49 1 9 1 10 MWell User Manual Send Support E Mail xj This problem r
15. 0 001 0 01 6 Sandy silt clayey silt 0 01 0 1 7 Silty sand sandy silt 0 1 1 8 Sand silty sand 1 10 9 Sand medium fine coarse 10 100 10 Sand gravel 100 1000 11 Very stiff fine grained soil 0 000005 0 005 12 Sand clayey sand 0 0005 1 If geological information indicates that inhomogenities occur in sediments much lower val ues for hydraulic resistance should be taken for clay and peat layers for clay around 100 to 1000 days per m layer thickness for peat around 10 to 100 days per m layer thickness Sheet piling flow resistance Sheet pilings may partially leak water This is dealt with by a resistance The higher the resistance the more impervious the sheet piling behaves The resistance can be derived from the reciprocal hydraulic joint resistance In the Sheet Pilings window the input value for the sheet piling resistance R must be calculated considering the sheet pile width b using the formula R b 7 6 p Table 7 2 gives informative values for the reciprocal hydraulic joint resistance Table 7 2 Average values for the reciprocal hydraulic joint resistance followed from tests performed for Arcelor Joint filler type Reciprocal hydraulic joint resistance p m d Open joints 110 Bitumen joint filler 1 1073 Swelling joint filler material 1 1074 to 1 10 Obviously it is possible to model the application of slurry walls using the sheet piling module In that case of a slurry w
16. 0 0307 moderate 20 20 0 0511 0 0170 stiff 21 22 21 22 0 0329 0 0230 0 1100 0 0077 very sandy stiff 19 20 19 20 0 0511 0 0329 0 0170 0 0110 Clay clean weak 14 14 0 3286 0 1095 moderate 17 17 0 1533 0 0511 stiff 19 20 19 20 0 0920 0 0767 0 0307 0 0256 slightly sandy weak 15 15 0 2300 0 0767 moderate 18 18 0 1150 0 0383 stiff 20 21 20 21 0 0767 0 0460 0 0256 0 0153 very sandy stiff 18 20 18 20 0 0920 0 0164 0 0307 0 0055 organic weak 13 13 0 3067 0 1022 moderate 15 16 15 16 0 2300 0 1533 0 0767 0 0511 Peat not preloaded weak 10 12 10 12 0 4600 0 3067 0 1533 0 1022 moderate preloaded moderate 12 13 12 13 0 3067 0 2300 0 1022 0 0767 Tf no high value is mentioned then the value of the underneath line of the Low column must be applied On demand a spreadsheet is available at Delft GeoSystems that can calculate possible input values for the oedometer stiffness on the basis of soil profile information for a project When selecting values for the stiffness the user must consider in which compressible and hydraulic resistant layer the consolidation process could occur This is to establish the proper consolidation and settlement behavior of the aquitard accounting for the groundwater lowering in a neighboring aquifer After introducing the value for the oedometer stiffness the program returns a value for the specific storage If the input in the profile window needs to be used to model
17. 3 m d d d m cluster 75 000 500 000 0 000 90 000 0 500 2 v 3w 12 25 000 50 000 500 000 30 000 120 000 0 500 2 v a 25 000 50 000 500 000 0 000 90 000 0 500 3 v 14 75 000 50 000 500 000 30 000 120 000 0 500 3 v 75 000 0 000 500 000 0 000 90 000 0 500 1 25 000 0 000 500 000 30 000 120 000 0 500 1 v 25 000 0 000 500 000 0 000 90 000 0 500 2 v 75 000 0 000 500 000 30 000 120 000 0 500 2 v Cancel X co ordinate Z co ordinate Figure 4 7 Discharge Wells window The position in the geometry in X Z coordinates m Discharge The required discharge m day In case of recharge infiltration a nega tive discharge has to be entered Switch On The point of time the well starts pumping day Switch Off The point of time the well stops pumping day Diameter Total diameter of the well borehole also including a gravel casing m Filter in The soil cluster where the filter of a well is installed filters are fully pene cluster trating the aquifers 24 of 49 Deltares 4 2 3 Input If the location of a well coincides with a mesh point the value of heads will be calculated at a distance from the well equal to half the well diameter It might be easy to use the edit buttons at the left side of the well table By dragging the arrow left of the table several lines can be selected from the table By copying the well data to a spreadsheet editing of well information and pasting back to th
18. 55 000 El 40 000 58 000 5 ala 40 000 63 000 3 40 000 70 000 Cancel Figure 5 1 Monitoring Points window 5 1 2 Contouring Times Contouring calculations in MWell are performed at all node points of the mesh in the aquifers of all clusters for a range of times Deltares 29 of 49 MWell User Manual H Contouring Times x Time day 7 000 30 000 90 000 360 000 ATA Cancel Figure 5 2 Contouring Times window The points of time days can be entered in the table of the dialog box By giving lt enter gt after each value a new cell can be filled At the left of the window three buttons are available to insert or add or delete cells during editing The next three buttons are for the normal Windows actions cut copy and paste The buttons become active after dragging down the arrow in front of the table These options allow the user to communicate between MWell and other Windows products like a spreadsheet or text editor 5 1 3 Monitoring Times Time history calculations in MWell for which specific monitoring points were selected before section 5 1 1 need the definition of a time range The calculations will be performed at regular time intervals The time history data must be introduced in the Monitoring Times window Monitoring Times x Time history range First time day 10 000 Last time day 1000 000 Discretisation E 50 Cancel Figure 5 3 Monitoring
19. Deltares systems Deltares Enabling Delta Life yA User Manual MWell Design and design check for multi layer well systems User Manual Version 15 1 Revision 41593 24 September 2015 MWell User Manual Published and printed by Deltares telephone 31 88 335 82 73 Boussinesqweg 1 fax 31 88 335 85 82 2629 HV Delft e mail infoOdeltares nl P O 177 www https www deltares nl 2600 MH Delft The Netherlands For sales contact For support contact telephone 31 88 335 81 88 telephone 31 88 335 81 00 fax 31 88 335 81 11 fax 31 88 335 81 11 e mail sales deltaressystems nl e mail support deltaressystems nl www http www deltaressystems nl www http www deltaressystems n Copyright O 2015 Deltares All rights reserved No part of this document may be reproduced in any form by print photo print photo copy microfilm or any other means without written permission from the publisher Deltares Contents Contents 1 General Information 1 tl Prenga A 1 1 2 Features in standard module ke 1 Ea JET it a III 2 1 4 Assumptions and Limitations k ke 2 1 5 Minimum System Requirements lt ke 3 1 6 Definitions and Symbols L 3 AA 4 18 Gelling Support 2 lt lt sa acos so A 4 19 Deltares lt suus a K le k kee O vie ksi dle 6 1 10 Deltares Systems lt kk J I ILIN 6 2 Getting Started 7 2 1 Starting MWell 9 MB 7 2 2 MainWindow 49 Who
20. Times window First time First and last time of the time range Last time Discretisation Enter the number of interval time points discretization with regular in tervals 30 of 49 Deltares 5 2 Calculations Start Calculation After selecting the Start option from the Calculation menu the Start Calculation window ap pears Calculation type Numerical precision Sheet piling implementation Calculation progress Deltares Start Calculation xj Calculation type JY Contour plo I Time history chart Numerical precision Number of stehfest terms H 12 Sheet piling implementation Analytical approach Numerical simulation mann 16 EN Calculation progress Cancel Figure 5 4 Start Calculation window The calculation type specifies if contouring plots are to be determined or time history charts or both Selecting one or the other option might reduce calculation time during study of a problem The number of Stehfest terms is requested to perform the calculation with desired precision The necessary input looks like a sincere ana lytical knowledge is presumed However the user might suffice with a default value of 1 For the explanation the user is referred to the Theory Chapter at the end of this manual The number of terms affects the ac curacy The runtime of the program will keep pace with the number of terms Because it is found in practice that a too high number could give
21. a phreatic groundwater layer the user should give a value in such manner that the specific storage is set to a value close to the porosity of the present phreatic soil layer Deltares 47 of 49 MWell User Manual 48 of 49 Deltares Bibliography NEN September 2006 NEN 6740 2006 Dutch Design Code Geotechnics TGB 1990 Basic reguirements and loads Deltares 49 of 49
22. all the resistance must be calculated considering the specific material for the cut off wall with a permeability k and a wall thickness d using the formula d R 7 7 Values of permeability of wall material may vary between k 107 m d for cement bentonite to 107 m d for concrete not counting imperfections like cracks or gaps Deltares 45 of 49 7 7 7 8 MWell User Manual Specific storage coefficient The specific storage S of the layers as input parameter for the time dependent calculations is evaluated by the program from other parameters like porosity n bulk modulus of the ground water K and oedometer stiffness E cg of the soil n l n 1 gt Yw D 7 8 E K 7 l Since the bulk modulus of soil particles K goes to infinite the formula is simplified to n 1 S Ww D 7 9 E ij Some values of porosity for input in the Profile window may be found in the next table Table 7 3 Typical values of porosity for different soil types Soil type Porosity n Gravel 25 35 Sand 30 45 Peat 80 90 Clay 70 80 Oedometer stiffness The oedometer stiffness is a geotechnical parameter describing the unidirectional compres sion behavior of soil under an infinitely extending load The oedometer stiffness can be evaluated from the consolidation ratio CR accounting for the level of effective stresses s at the depth of the soil layer 2 30 CR If the soil beh
23. an erroneous oscillation of the solution the maximum was set to 7 In earlier versions of MWell the default number was set to 2 However with sheet piling calculations it was found that oscillation might also occur with this number of terms Since the accuracy was good enough with a value of 1 the default was reset to this number in MWell 3 0 To give the user the opportunity to validate models for the effect of the Stehfest number the possibility was introduced in the Start Calculation Window to change the proposed default value Only available if the Sheet piling option in the Model window sec tion 4 1 1 is activated and if a sheet piling is inputted in the Sheet Pilings window section 4 2 3 Two options for the calculation method are available to choose from an analytical or a numerical approach of the solution If the last option is selected the program needs a value for the segment length amplifier For more information on this subject the user is referred to the Theory Chapter The advancement of the calculation process is indicated with two progress bars 31 of 49 5 3 5 4 MWell User Manual Warning All input parameters have upper and lower bounds set by the program The bounds allow all values that are most common in practice It is the responsibility of the user to choose realistic values to guarantee a reliable outcome for the problem at hand Table 5 3 Limits input in MWell Paramete
24. aves rather stiff due to former loading by geological phenomena groundwater lowering embankments or other soil loads it is probably acceptable to use the reconsolidation ratio RR Esa 7 10 2 30 RR Elaboration of proper model parameters of oedometer stiffness must be done outside the program by the user To get the right CR and RR parameter values useful information might be found in Table 1 of the Dutch geotechnical guideline NEN 6740 NEN September 2006 copied as the next table Egea 7 11 46 of 49 Deltares Theory of groundwater flow Table 7 4 Low and high representative values of the ground parameters acc to Table 1 of NEN 6740 Main Addition Consistency Y Ysat CR C 1 eo RR C 1 eo pane KN m kN m Low High Low High Low High Low High Gravel slightly silty loose 17 19 0 0046 0 0015 moderate 18 20 0 0023 0 0008 stiff 19 20 21 22 0 0019 0 0016 0 0006 0 0005 very silty loose 18 20 0 0058 0 0019 moderate 19 21 0 0038 0 0013 stiff 20 21 22 22 5 0 0023 0 0015 0 0008 0 0005 Sand clean loose 17 19 0 0115 0 0038 moderate 18 20 0 0038 0 0013 stiff 19 20 21 22 0 0023 0 0015 0 0008 0 0005 slightly silty moderate 18 19 20 21 0 0051 0 0035 0 0017 0 0012 very silty loose 18 19 20 21 0 0115 0 0058 0 0038 0 0019 Loam slightly sandy weak 19 19 0 0920
25. c rociar da ra Ree ee soi mk 35 6a Time Nistay ONEN co a E a ee a em 37 7 Theory of groundwater flow 39 fl Basic EQUIM NS lt lt lt cs ca se aone meua du name edoa IK 39 YE SOC MStiod 2 lt se Sa meaa ses a A E R a 40 7 3 Groundwater flow and sheet pilings K 40 Fa BEIKOPOUiBO lt lt ss 705 doda mn e Koo a Ee ee 40 7 3 2 Accuracy of the calculations ee eee 41 7 3 3 Use of sheet pilings in MWell Ae 42 7 3 4 Example of the effect of sheet pilings from the Results menu 43 7 4 Hydro geological parameter values Ke 44 7 5 Permeability Transmissivity and Resistance 44 7 6 Sheet piling flow resistance s a a a 45 7 7 Specific storage coefficient a e 46 7 8 Oedometer stiffness BY Qe 46 Bibliography 49 iv Deltares List of Figures List of Figures 1 1 1 2 1 3 1 4 2 2 2 2 3 2 4 25 2 6 3 1 3 2 3 3 3 4 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8 4 9 4 10 4 11 5 1 5 2 5 3 5 4 6 1 6 2 6 3 6 4 E 72 7 3 Deltares MWell Contouring PIOT lt acs be By s g 8 das Joa MON mat KON Software menu of the Deltares Systems website www deltares com Support window Problem Description tab L Send Support E Mail window L Modules WINDOW cocos a soe moraa aaa aapa Ala a MWell main window L a MWel menu bar iu rraca sadresa ru daaa ee be ay MWe icon baf 1 lt a s an dc Gre
26. checkbox to display the horizontal and vertical rulers Mark this checkbox to display the mesh Mark this checkbox to display values labels When using this option the distance between the value labels for the contouring must be entered The contour options concern the presentation of colored areas shades and or lines For the presentation of colors a palette must be chosen This palette is also used for the presentation in the legend The contour range defines the number of color areas or lines to be drawn The options are to use an automatic division in steps or to have it manually selected by the user In the last case the user must define a minimum and maximum level for the contouring and a step value The same setting of these contour ing ranges will also be requested in the Results Contour Plot Options Deltares 4 1 4 4 2 4 2 1 Input View Input File On the menu bar click Project and then choose View Input File to display an overview of the input data The data will be displayed in the MWell main window Click on the Print Active Window icon El to print the file Geometry menu Every new analysis starts with the input of data on the soil profile the discharge wells the sheet pilings if present and the mesh Profile The Profile window needs input information about the hydraulic parameters in a schematiza tion of aquitards and aquifers The calculation method is based on a scheme of an aquitard top
27. current date on each printout or enter a specific date Enter the name of the user performing the calculation or gener ating the printout Enter a project identification number Specify the annex number of the printout Mark the checkbox Save as default to use these settings every time MWell is started or a new project is created Project Properties Input View Use the Input View tab to specify the lay out of the input view Project Properties xi Identification Input View Contour Plot Options Display Grid IV Rulers Y Show grid IV Info bar I Snap to grid IV Same scale for X and Z axis Grid distance m fioo Items IV Wells IV Monitoring points IV Labels Save as default Cancel Figure 4 4 Project Properties window Input View tab Rulers Info bar Same scale for X and Z axis Show grid Snap to Grid Grid distance Wells Monitoring points Deltares Mark this checkbox to display the horizontal and vertical rulers Mark this checkbox to display the information bar at the bottom of the Input Diagram window Mark this checkbox to use the same scale for the horizontal and vertical directions Mark this checkbox to display a grid in each Input Diagram win dow Mark this checkbox to ensure that objects align to the grid auto matically when they are moved or positioned in a drawing win dow This option applies only to graphical input Use this field to set the distance betw
28. e shown at start up For a MWell installation based on a license dongle the Modules tab will just show the modules that may be used Deltares 17 of 49 MWell User Manual 3 3 Help menu The Help menu allows access to Get on line help using the MWell Help option refer to section 1 7 for a detailed descrip tion of this window View Error Messages View the Manual Visit the Deltares Systems Website for the latest news Use the Support option to register program errors refer to section 1 8 for a detailed description of this window Display the About box of MWell About MWell 18 of 49 Deltares 4 4 1 Input MWell facilitates calculation of pumping in multi layered subsoil The filters are placed in aquifers which are separated by aquitards The flow can be manipulated by placing semi impermeable walls sheet pilings The drawdown and the settlements in all aquifers are determined Material data consist of height transmissivity oedometer stiffness and porosity for the aguifers and height resistance oedometer stiffness and porosity for the aguitards The height of the individual layers is shown in the vertical cross section of the stratification All programs by Delft GeoSystems like MWell take the Y coordinate for the vertical direction As a result the position in the horizontal plane is defined by the X and Z co ordinates The wells require a discharge positive value for pumping or a
29. een grid points Mark this checkbox to display Wells in the Input Diagram window This option is available only for a sheet pile wall or a pile loaded by forces Mark this checkbox to display monitoring points in the Input Dia gram window 21 of 49 MWell User Manual Labels Mark this checkbox to display labels in the Input Diagram win dow Project Properties Contour Plot Settings Use the Contour Plot Settings tab to specify the display of the Contour Plot window Project Properties xl Identification Input View Contour Plot Options Display I Info bar IV Same scale for X and Z axis Show values in plot Y Legend W Rulers Interval fi JV Options panel Mesh Contour options W Shades visible T Lines visible IV Auto refresh Palette Legend decimals 2 Contour range Auto Range Shades fro Manual Range Minimum 40 00 Maximum fio 00 Step 41 00 I Save as default DK Cancel Topaz X Figure 4 5 Project Properties window Contour Plot Settings tab Info bar Legend Options panel Same scale for X and Z axis Rulers Mesh Show values in plot Contour options Contour range 22 of 49 Mark this checkbox to display the information bar at the bottom of the Contour Plot window Mark this checkbox to display the legend Mark this checkbox to display the options panel Mark this checkbox to use the same scale for the horizontal and vertical directions Mark this
30. ell is started by double clicking on an input file Save on Calcula tion The toggle buttons determine how input data is saved prior to calculation It can either be saved automatically using the same file name each time or a file name can be specified every time the data is saved 16 of 49 Deltares General Use Enter Use the toggle buttons to determine the way the Enter key is used in MWell key to either as an equivalent of pressing the default button Windows style or to shift the focus to the next item in a window for users accustomed to the DOS version s of the program Locations xi Modules View General IV Save last used current directory as working directory Working directory D MWELL MWell 3 2 Verification B enchmark Figure 3 3 Program Options window Locations tab Working MWell will start up with a working directory for selection and saving of files directory Either choose to use the last used directory or specify a fixed path Modules xi View General Location License FlexLm JV Mwell Base module IV Sheet piling Evaluation mode IV Show at start of program Figure 3 4 Program Options window Modules tab For a MWell installation based on floating licenses the Modules tab can be used to claim a license for the particular modules that are to be used If the Show at start of program checkbox is marked then this window will always b
31. eport will be sent to support delftgeosystems nl You can also send the current file as an attachment Check the checkbox below to do this Sending of the problem report with E mail is only possible if the mail program on your system is configured as default Simple MAPI client consult pour system administrator This will only work if your E mail program can reach external Internet E mail addresses Cancel Help Figure 1 4 Send Support E Mail window The problem report can either be saved to a file or sent to a printer or PC fax The document can be emailed to geo support deltaressystems nl or alternatively faxed to 31 0 88 335 8111 Deltares Since January 1 2008 GeoDelft GeoDelft together with parts of Rijkswaterstaat DWW RIKZ and RIZA WL Delft Hydraulics and a part of TNO Built Environment and Geosciences are forming the Deltares Institute a new and independent institute for applied research and specialist advice Founded in 1934 GeoDelft was one of the world s most renowned insti tutes for geotechnical and environmental research As a Dutch national Grand Technological Institute GTI Deltares role is to obtain generate and disseminate geotechnical know how The institute is an international leader in research and consultancy into the behavior of soft soils sand clay and peat and management of the geo ecological consequences which arise from these activities Again and again subsoil related uncertain
32. erformance Two types of numerical instability may occur Singular behavior of the value matrices due to large contrasts in the soil parameters in a many layered system Divergent behavior in the Stehfest inverse placeLaplace transformation this rarely hap pens close after the start of pumping 1 5 Minimum System Requirements The following minimum system requirements are needed in order to run and install the MWell software either from CD or by downloading from the Deltares website via MS Internet Ex plorer Operating systems Windows 2003 Windows Vista Windows 7 32 bits Windows 7 64 bits O O O O O Windows 8 Hardware specifications 1 GHz Intel Pentium processor or equivalent 512 MB of RAM 400 MB free hard disk space SVGA video card 1024 x 768 pixels High colors 16 bits CD ROM drive Microsoft Internet Explorer version 6 0 or newer download from www microsoft com o O O O O O 1 6 Definitions and Symbols Soil 0 Ez Deltares Vertical effective stress positive in compression Vertical strain positive in compression Hydraulic head by flow and deformation Variation of water storage i e drawdown Time Thickness of an aguifer Thickness of a semi impervious layer i e aguitard Horizontal hydraulic conductivity of an aguifer Vertical hydraulic conductivity of a semi impervious layer i e aguitard 3 of 49 1 7 1 8 MWell User Manual
33. errors must be corrected first before performing a new calculation 32 of 49 Deltares 6 View Results 6 1 As soon as computation results are present they may be viewed If in the meanwhile the input has been changed a message appears with the suggestion to calculate first Outcome is presented as contour plots time history charts and output reports Through the help of the plots and charts the drawdown or the settlements can be observed The options in the Results menu can be used to view the results of the performed calculations ResultsSee View results Report A short or a long version of the output file can be created The output file weo is created each time a calculation is performed Viewing the file can be done by Results Output Report The short version contains the following O program name and version update company name license and data and time of run ning the program echo of the input the points of time of calculation if contour plot is applied the X Z coordinates of calculation if time history chart is applied Deltares 33 of 49 MWell User Manual Unknown 11 17 2009 4 40 00 PM 2 D MWVELL MWJell 3 2 User Manual Tutorials demo 1 weo MWell version 3 2 1 2 BEGINNING OF DATA RUN IDENTIFICATION Demo 1 for MWell CLUSTER LIST 9 81 2 unit weight of water 100000 bulk modulus of water number of items Identifier 32768 1 00 100 00 4 91E 02 13697023 4 00 50 00
34. et piling number as shown in figure 1 The user could assume that two sheet pilings may be precisely connected as if it were one single wall Yet in the calculations these systems behave differently This is due to the fact that in MWell a sheet piling has no width As a result there will always be a leak between two such segments even if connected at infinitesimal small distance 42 of 49 Deltares Theory of groundwater flow Sheet pilings are applied per soil cluster aquifer plus aquitard above Currently only one clus ter number may be specified per sheet piling number If the sheet piling carries on over more clusters this must be specified by introducing several sheet pilings at the same coordinates but in different clusters numbers Sheet pilings may partially leak water This is dealt with by a resistance The higher the resistance the more impervious the sheet piling behaves Currently the resistance is constant per sheet piling The resistance can be derived from the reciprocal hydraulic joint resistance In the sheet pile dialog window the input value for the sheet piling resistance R must be calculated considering the sheet pile width b using the formula R 7 3 l0 x Data Cluster 1 Time 9000 z Aulo janga Shades 10 A ToManual Data Drawdown Y lt lt Options Manual range Min 4875 Max 5oo0 Stenf0 025 la a TERN KOR NR VT IEEE Figure 7 3 Contour Pl
35. h is to be at the centre of the new image Zoom out Click this button and then click on the drawing to reduce the drawing Zoom area Click this button then click and drag a rectangle over the area to be enlarged The selected area will be enlarged to fit the window Measure the distance between two points Click this button then click the first point on the Input Diagram window and place the cross on the second point The distance between the two points can be read at the bottom of the Input View window To turn this option off click the escape key Add Well Click this button to add wells Add Monitoring Place Click this button to add monitoring points Undo Zoom Click this button to undo the zoom Zoom limits Click this button to display the complete drawing 10 of 49 Deltares 2 2 4 Getting Started Mesh On Off Click this button to view or not the mesh For more information see section 4 2 Stratification window profile with soil clusters The stratification window at the right of the main window displays the soil profile soil consisting of a number of soil clusters Figure 2 6 A cluster is a semi pervious low permeability layer aguitard on top of a permeable layer aquifer The flow in the aguitard is mainly vertical while the flow in the aguifer is mainly horizontal The layers have a constant thickness and extend to infinity Clusters are numbered The number is
36. i layered Its restriction concerns its homo geneous character and unlimited geometry Therefore confining elements as sheet piles are not easily accommodated A sheet piling causes a discontinuity in the groundwater head For the computation by MWell this behavior is programmed by a special combination of wells double root doublets These elements consist of rows of two wells of opposite strength placed infinitely close to each other and lined up along the sheet pile The strength of such a doublet is the size of the discontinuity These strengths are not known beforehand They depend on the other elements involved the wells For every group of wells switched on at the same time and every group switched off at the same time a sheet pile module must be supplied The sheet piles imply conditions concerning the discharge for the flow The conditions result in a system of integral eguations Its solution supplies the reguired strength for the discontinuity over the sheet pile wall so that the drawdown in the field is determined correctly The integral eguations cannot be solved in an analytical fashion Numerical technigues are reguired The sheet piles are subdivided into smaller elements where a linear strength is assumed After elaboration a matrix eguation is composed by which the strengths are fixed 40 of 49 Deltares 7 3 2 Theory of groundwater flow The user is not aware of the use of doublets in the program but only indica
37. is dialog box in MWell a quick working process is at hand if large numbers of wells are needed Sheet Pilings In MWell the option to use Sheet pilings is available in a separate module When available in the current license the module can be used after checking the Sheet piling option in Tools Program Options Modules Once checked it may be switched on off via Projects Model Sheet pilings are entered via the menu option Geometry Sheet Pilings xi Sheet piling number x co ordinate m Z co ordinate m 1 75 000 50 000 2 2 75 000 50 000 3 4 ES E Cluster fi y Resistance day 10000 cena Figure 4 8 Sheet Pilings window X co ordinate The position in the geometry in X Z coordinates m Z co ordinate Cluster Select the cluster number where the selected sheet piling is present Resistance Enter the hydraulic resistance day In the Input Diagram window the sheet pilings as introduced by the user will be shown with dark red lines Deltares 25 of 49 4 2 4 MWell User Manual Bittern Aen B A HAI wu Puun A E as SH JE on 3 3 E 104 003 znano Ea Figure 4 9 Input Diagram window showing the sheet pilings the discharge wells and the monitoring points ao zlu Because sheet pilings can only be entered through the Sheet Pilings window of the Geometry menu there is no dropping or dragging edit
38. k Aavan A a da a ooi Input Diagram window lt lt kkk Bo Stratification Window L Program Options window View tab L Program Options window General tab L Program Options window Locations tab LL Program Options window Modules tab L Model window N N OYJ Location Map window aoaaa a a a Project Properties window Identification tab lt L Project Properties window Input View tab ie Project Properties window Contour Plot Settings tab Profile window SML e JY VV Discharge Wells window Wh 988 1 Sheet Pilings window S Aon TIKKA KK ke Input Diagram window showing the sheet pilings the discharge wells and the monitoring points AP AA KN KAA KK kka Mesh window 487 88 AA Water Properties window m k e Monitoring Points window e Contouring Times WM GW lt lt kk k ke A Monitoring Times window o o Start Calculation window 2 ee a Report window short report e Contour Plot window for Drawdown L Contour Plot window for Settlement L Time History Chart window n kk Start Calculation window L Time History Chart window aa 2380840404 I hokan ea Contour Plot window 2 oo so sa ce moe ks POS AS TS And a MWell User Manual vi Deltares List of Tables List of Tables 5 3 7 1 12 7 3 Deltares Limite input m MWe y i son e id 0808 32 Typical values of the hydraulic conductivity
39. le wec is generated during calculation This dumpfile is used to visualize the drawdown and settlements during Results Contour Plot The long output report contains the dumpfile data too Contour Plot Layer sand in stratum 1 lo x Data Options Cluster E Time 700 z Autorange Shades fio A ToManval Manualrange Hin 2 00 Mar 10 00 Stenl1 00 Data Drawdown v lt lt Options Figure 6 2 Contour Plot window for Drawdown Deltares 35 of 49 MWell User Manual Wi Contour Plot Layer sand in stratum 1 0 xj Data Dptions Cluster MN 7 Time 700 v Autorange Shades 10 3 ToManual Data Settlement y lt lt Options C Manualrange Kin feo Mex 10 00 Stepf1 00 116 44 mm 100 so a Figure 6 3 Contour Plot window for Settlement The contour plots for all layers and times are available The way to present the plots is flexible The following items may be adjusted o The contour lines The minimum the maximum and the step size may be specified Drawdown and set tlement have both their own settings Initially the minimum and maximum values found during calculation are displayed The point of time The required point of time for the contouring may be selected by an up down facility which contains the range of specified times o Presentation The color scheme may be chosen To select a color scheme the right mo
40. m window The nput Diagram window graphically displays the input in two separate sub windows atop view layout of the wells avertical cross section of the stratification In case of a new file both sub windows are empty Editing wells is performed by the technigue of selecting dragging and double clicking on the corresponding item or by using the Edit panel Deltares 9 of 49 MWell User Manual MWell C A MWell Projects Examples demo 2 l0 x File Project Geometry Water Calculation Results Tools Window Help ODGaA ERE a B o o HM Input Diagram AER Edit R 200 150 100 50 O 50 Ts R a e e ISE u IS iS holoceen amp 507 1007 kreftenheie fa x 65 283 2 162 410 Edit Figure 2 5 Input Diagram window Click on the buttons in the Edit or Tools panel to activate the corresponding functions y Select and Edit In this mode the left hand mouse button can be used to select previously defined supports loads and layers in the Input Diagram ltems can then be deleted or modified by dragging or resizing or by clicking the right hand mouse button and choosing an option from the menu displayed Pressing the Escape key will return the user to this Select and Edit mode Pan Click this button to move the drawing by clicking and dragging the mouse Zoom in Click this button to enlarge the drawing and then click on the drawing on the part whic
41. me history chart and analysis of the drawdown and settlements based on input values chapter 5 Results Options for creating report and displaying the drawdown and settlements us ing contour plots or time history charts chapter 6 Tools Options for editing MWell program defaults section 3 2 Window Default Windows options for arranging the MWell windows and choosing the active window Help Online Help options section 1 7 Detailed descriptions of these menu options can be found in the Reference section 8 of 49 Deltares 2 2 2 2 2 3 Getting Started Icon bar Use the buttons on the icon bar to quickly access frequently used functions see below Buttons on icon barlcon bar DORA ERE o Figure 2 4 MWell icon bar Click on the following buttons to activate the corresponding functions Start a new MWell project B Open the input file of an existing project m Save the input file of the current project a Print the contents of the currently active window Display a print preview of the current contents of the Input Diagram window Open the Project Properties window Here the project title and other identifi E cation data can be entered and the Diagram Settings and Graph Settings for the project can be determined Start the main calculation Display the contents of online Help 9 Display the first page of the Delft GeoSystems website KA www delftgeosystems nl Input Diagra
42. n After solving the flow problem the result must be transformed back to the original domain Stehfest introduced a method using a progression of mathematical functions to perform this back transformation Two types of numerical instability may occur Singular behavior of the value matrices due to large contrasts in the soil parameters in a many layered system Divergent behavior in the Stehfest inverse Laplace transformation this rarely may hap pen close after the start of pumping The number of terms affects the accuracy The runtime of the program will keep pace with the number of terms Because it is found in practice that a too high number could give an erroneous oscillation of the solution the maximum was set to 7 In earlier versions of MWell the default number was set to 2 However with sheet piling calculations it was found that oscillation might also occur with this number of terms Since the accuracy was good enough with a value of 1 the default was reset to this number in MWell 3 0 Groundwater flow and sheet pilings Background In the analytical approach in MWell still numerical methods are applied to reach the solution of flow problems in an efficient way The accuracy of the numerical evaluation depends on the adjustment of control parameters as explained in section 7 3 2 MWell is a tool to determine the effects of dewatering It targets on the use of Wells The flow behavior is transient and the geometry is mult
43. n approach according to Stehfest Features in standard module MWell determines the transient flow and settlement by pumping with fully penetrating wells in a set of horizontal permeable aguifers and less permeable aquitards MWell gives quick solutions and is easy to use The following features are included multi layer geometry transient flow process several pumping units per layer Two types of graphical output O time history plot O contouring plots in SURFER format An example of a contouring plot is presented in the figure below The geometry consists of three sand layers In the middle one four pumps are placed In the bottom one four pumps too The interaction between the layers is clearly visible Deltares 1 of 49 MWell User Manual ai oh ay 5 2 254 pl iS le 1 14 y a A I l ia El li ETE A ae ol E Ji PA l l 25 eal jes L 4 I in ISI JN yr S so Ga gt N ye E JOO Sy 75 tt t Figure 1 1 MWell contouring plot 1 3 History The first version of MWell was built by GeoDelft in 1997 based on the mathematical method developed by Maas 1983 Release 2 7 2003 uses a new licensing method The storativity parameter has been replaced by the oedometer stiffness The deformation contribution of aguifers is now included in the total se
44. option in this field for these elements A sheet piling consists of a series of sheet piles One segment of a sheet pile wall is specified by consecutive begin and end co ordinates The sheet pile wall is hydraulically closed from a theoretical viewpoint if the last end point coincides with the first begin point In that case a location or building pit is completely surrounded with sheet piles The issue of closed needs some explanation A geometrically closed sheet piling may be composed of one single segment with one sheet piling number as shown in the figure The user could assume that two sheet pilings may be precisely connected as if it were one single wall Yet in the calculations these systems behave differently This is due to the fact that in MWell a sheet piling has no width As a result there will always be a leak between two such segments even if connected at infinitesimal small distance Sheet pilings are applied per soil cluster aquifer plus aquitard above Currently only one clus ter number may be specified per sheet piling number If the sheet piling carries on over more clusters this must be specified by introducing several sheet pilings at the same coordinates but in different clusters numbers Mesh The mesh in MWell is used to define the points in the X Z plane for which calculations of head and settlement will be performed by the program On the basis of the calculated drawdown at the mesh points a contour
45. ot window The discontinuity in the groundwater level at the sheet piling walls can be seen in the Contour Plot window from the Results menu Figure 7 3 The user should be aware of the discontinuity in head near the sheet piles when he designs the step size for the isolines The drop in groundwater head might be reasonably large It is recommended to go from Auto range first and then to a full Manual range with small step size before selecting smaller ranges To illustrate the effect of sheet pilings on the drawdown a case with sheet pilings around two building pits is computed One sheet pile wall is truly closed the other is composed of a U shaped sheet pile wall and a straight sheet pile wall The latter is leaky at the connections To achieve the same average drawdown the latter sheet piling is drained by a 10 times bigger discharge than the closed one The discharge is returned into the aquifer again in three infiltration wells next to each building pit In the figure the drawdown is shown This type of presentations is of main interest to un derstand the conseguences of a drainage schedule For instance the effect of the return discharges in case of the leaky sheet piling Deltares 43 of 49 7 4 7 5 MWell User Manual Hydro geological parameter values To select proper values for input parameters the user should have a basic knowledge of hy drogeology Permeability Transmissivity and Resistance Values for input parameter
46. ping an aquifer One aquitard and one aquifer are taken together in a so called cluster For each layer of soil material specific data must be defined This concerns aquitard data as well as aquifer data Height permeability oedometer stiffness and porosity are required In the aquifer the product of height and permeability is called transmissivity in the aquitard the ratio of height and permeability is called hydraulic resistance Height is used to draw the vertical cross section in the stratification window x Aguitard data Cluster number Height m 100 2 Resistance day 100 00 i Dedometer stiffness kPa 4 31E 02 Ea Specific storage 1 998E 02 Name Porosity 2 60 000 ely Aquifer data Height m 4 00 Transmissivity rrR day 50 00 Col Dedometer stiffness kPa 7 85E 03 Color Specific storage 4 999E 03 Name Add Insert Delete Porosity 140 000 sand om Figure 4 6 Profile window Height Enter the height of the aquitard Resistance Enter the hydraulic resistance of the aguitard which is the ratio of the height and the hydraulic conductivity permeability Transmissivity Enter the transmissivity of the aguifer which is the product of the average hydraulic conductivity permeability and the height of the aquifer Oedometer Enter the oedometer stiffness This geotechnical parameter describes the stiffness unidirectional compression behavior of soil under an infinitely extending
47. plot is interpolated when showing the results The mesh is set by introducing the coordinates of the mesh window in the project coordinate dimensions The size that must be specified in the program defines the distance between mesh points 26 of 49 Deltares Input x Limits Size m 10 000 Left m 100 000 Bight m f100 000 Top m 110 000 Bottom m 415 000 Cancel Figure 4 10 Mesh window Size The required mesh distance Left The position in the geometry of the limits in the X Z coordinate plane of Left Right X Right X Top Z Bottom Z Top Bottom 4 3 Water menu 4 3 1 Water Properties The influence of the compressibility and the unit weight of groundwater are taken into account during calculation Their values are constant in the entire field In the window Water Properties window the specific characteristics for the water are defined The values are needed for the calculation of the specific storage coefficients Usually the user of the program will benefit from the default values for unit weight and bulk modulus as stated in the input fields Only in special cases e g flow of salt water or other fluids deviations of the default values will be needed Water Properties xj Unit weight kN m3 3 31 Bulk modulus kN m3 100000 Cancel Figure 4 11 Water Properties window Unit weight Enter the unit weight of water in kN m Bulk modulus Enter the bulk modulus of water in kN m
48. r Maximal dimension Mesh co ordinates 10 x 10 m to 10 x 10 m Number of mesh points 10000 Number of wells infinite 2 1 x 109 Number of sheet pilings 200 Number of clusters 9 Number of monitoring points 250 Number of monitoring times 5 x 105 Number of contouring times 250 With the specified maximum dimensions it should be possible to tackle the greater part of the dewatering problems for which MWell is intended If it is necessary for special cases to use larger dimensions the client is invited to contact the support office of Delft GeoSystems to reguest an adapted version of MWell The major computation scheme of MWell concerns matrix calculus Big contrasts in soil pa rameters may lead to singular behavior MWell reports when this occurs and calculation is aborted For time dependent calculations of hydro geological problems including sheet pilings the accu racy is influenced by the schematization method for the sheet pilings the number of Stehfest terms and the position of wells next to sheet pilings If the number of Stehfest terms is set to 1 itis not expected that problematic oscillations will occur in the time history results If they do come forward this could be at small time steps However the calculations will not be aborted Error Messages If errors are found in the input data any calculation can be performed and the Error Messages window opens in which more details about the error s are given Those
49. recharge negative value for infiltration a filter position and a time switch on and off Moreover the X Z position is specified and the effective radius of the well The latter is intended to include a gravel casing if any is present in the borehole for a well Before analysis can be started data s for the sheet pile wall soil loads and supports need to be inputted Project menu Each project starts with the selection of an analysis model and the entry of general details about the project Model On the menu bar click Project and then choose Model to open the input window In this window the Sheet piling option can be selected poda IV Sheet piling 7 Cancel Figure 4 1 Model window Location Map An important feature of MWell is the possibility to import a background picture This picture can be used for orientation when defining the positions of wells monitoring points and sheet pilings The background picture may be of different formats jpg joeg bmp emf wmf The limits of the picture must be specified in the coordinate system chosen for the definition of the project Deltares 19 of 49 MWell User Manual Location Map xj Background Picture Co ordinates Left m Right m Iop m Bottom m 150 000 IV Copy co ordinates to mesh on pressing OK OK Cancel Figure 4 2 Location Map window Background Picture The location of the file to import Co ordinates The
50. s can be taken from maps and databases An option is to evaluate the parameters from bore loggings This last method is elaborated here From the bore loggings the heights and conductivities of packages with stacked thin layers of clay peat and other low permeable soil must be processed by the user to get an input value for the hydraulic resistance c n C 7 4 v 7 4 i 1 where n Number of sub layers k Conductivity of each sub layer i d Thickness of each sub layer 2 In a comparable way the heights and conductivities of packages with high permeable soil of gravel and sand must be processed to get the input value for transmissivity k D n kD kid 7 5 i 1 where k Conductivity of the soil cluster D Thickness of the soil cluster Values for hydraulic conductivity of soil material can be found in professional literature on hydro geology Typical values could also be extracted from the next table It is mentioned by minimum and maximum values that the user must be aware of ranges for material properties 44 of 49 Deltares 7 6 Theory of groundwater flow Table 7 1 Typical values of the hydraulic conductivity for different soil types Type Soil description Conductivity min Conductivity m d max m d 1 Fine erosive material 0 000005 0 0005 2 Organic material peat 0 002 0 5 3 Clay 0 00001 0 0001 4 Silty clay clay 0 0001 0 001 5 Clayey silt silty clay
51. t aspect in improving geotechnical engineering results For more information about Deltares Systems geotechnical software including download options visit www deltaressystems com 6 of 49 Deltares 2 1 2 2 Getting Started This Getting Started chapter aims to familiarize the user with the structure and user interface of MWell The Tutorial section which follows uses a selection of case studies to introduce the program s functions Getting Started Starting MWell To start MWell click Start on the Windows menu bar and then find it under Programs or double click a MWell input file that was generated during a previous session For an MWell installation based on floating licenses the ModulesModules window may appear at startup Figure 2 1 Check that the correct modules are selected and click OK I xf 17 MWell Base module IV Sheet piling Y Evaluation mode JY Show at start of program Figure 2 1 Modules window When MWell is started from the Windows menu bar the last project that was worked on will open automatically unless the program has been configured otherwise under Tools Program Options Main Window When MWell is started the main window is displayed Figure 2 2 This window contains a menu bar section 2 2 1 an icon bar section 2 2 2 an Input Diagram window section 2 2 3 that displays the pre selected or most recently accessed project the Stratification window section 2 2 4 an info bar section 2 2 5 and a sta
52. t ue Mass Conservation Storage Equation with Darcy s Law Oe Oro Oo Po yn dd Ot head Or head dy head Oz K Ot do do Aquitard 0 0 a Ox Oy do Aquifer 0 i Oz where o kN m The vertical effective stress positive in compression Ez The vertical strain positive in compression Q m The hydraulic head by flow and deformation K kN m The bulk modulus of the pore fluid n The porosity Yf kN m3 The unit weight of the pore fluid days The time Khsad m days The Darcy permeability which relates specific discharge to gradi ents in hydraulic head q Khead VQ Boed kN m The oedometer stiffness of the drained soil skeleton 4 Eoea a Kp ge with Kp the bulk modulus of the drained soil skeleton and G the shear modulus The oedometer stiffness can also be deduced from a known con solidation coefficient c Egg lt Knead n Vf Cu Ki The assumption of zero horizontal flow in the aguitards means that the combination of egua tion 7 1 and 7 2 in one aguitard reduces to the well known one dimensional consolidation eguation Deltares 39 of 49 7 2 7 3 7 3 1 MWell User Manual The assumption of zero vertical flow in the aquifer means that the vertical strain in an aquifer is assumed to be constant along the height Solution Method MWell uses Matrix diagonalisation and a placeLaplace transformation technique to derive the time dependent solutio
53. tes the presence position and the hydraulic property of the sheet piles MWell provides sufficient input space for elements In the analytical multi layer groundwater flow program MWell the solution of time dependent flow problems is performed by a placeLaplace transformation After solving the flow problem the result must be transformed back to the original domain Stehfest introduced a method using a progression of mathematical functions to perform this back transformation Accuracy of the calculations The accuracy of the Stehfest inverse transformation is regulated by the number of involved terms Start Calculation xj Calculation type Report IZ Contour plo Short J Time history chart C Long Numerical precision Number of stehfest terms oy Sheet piling implementation Analytical approach Figure 7 1 Start Calculation window The runtime of the program will keep pace with this number of terms Because it is found in practice that a too high number could give an erroneous oscillation of the solution the maximum was set to 7 Since the accuracy generally is good enough for a value of 1 this default was set in MWell 3 0 To give the user the opportunity to validate models for the effect of the Stehfest number the possibility is introduced in the Start Calculation window to change the proposed default value In order to perform computations a system of integral eguations is decomposed in the cal culation process
54. ties and risks appear to be the key factors in civil engineering risk management Having the processes to manage these uncertainties makes Deltares the obvious Partner in risk management for all parties involved in the civil and environmental construction sector Deltares teams are continually working on new mechanisms applications and concepts to facilitate the risk management process the most recent of which is the launch of the concept GeoQ into the geotechnical sector For more information on Deltares visit the Deltares website www deltares nl Deltares Systems Deltares Systems formerly known as Delft GeoSystems was founded in 2002 The com pany s objective is to convert Deltares knowledge into practical geo engineering services and software Deltares Systems has developed a suite of software for geotechnical engineering Besides software Deltares Systems is involved in providing services such as hosting on line monitoring platforms hosting on line delivery of site investigation laboratory test results etc As part of this process Deltares Systems is progressively connecting these services to their software This allows for more standardized use of information and the interpretation and comparison of results Most software is used as design software following design standards This however does not guarantee a design that can be executed successfully in practice so automated back analyses using monitoring information are an importan
55. ttlement Release 2 8 2004 has some corrections in the user interface Plots have been im proved by added a title header with relevant information The Help file was updated Release 3 1 2008 facilitates also to calculate the effect of the presence of low perme able walls fully penetrating in an aguifer on groundwater flow Release 3 3 2011 improves the implementation of Stehfest for projects with sheet piling defined Release 14 1 2014 includes minor fixes in the user interface and a new license sys tem 1 4 Assumptions and Limitations o The program calculates drawdown with respect to an initial groundwater level with a zero setting All layers have a constant thickness and extend to infinity Every separate layer is homogeneous and completely saturated The flow in the permeable aquifers is only horizontal the flow in the less permeable aquitards is only vertical 2 of 49 Deltares General Information o Each well has a filter over the complete height of one aquifer o Each flow resisting wall from now on referred to as Sheet Piling is present over the complete height of one aquifer Horizontal deformations are assumed to be zero Only the influence of drawdown on settlements is considered the influence of dead weight and soil loads is neglected The analytical calculation method has in principle no limitations However numerical accuracy of the computer may interfere with the p
56. tus bar section 2 2 6 The Input Diagram window displays a top view layout of the wells and the Stratification window shows a vertical cross section of the stratification In case of a new file both windows are empty Deltares 70f 49 MWell User Manual MH Mwell C MWell Projects Examples demo 1 15 xj File Project Geometry Water Calculation Results Tools Window Help OGa GQ Ble o put Diagra Edit AH i PP s K cz so A Ta Measure the distance between two points T course sand Measure the distance between two points Figure 2 2 MWell main window 2 2 1 Menu bar To access the MWell menus click the menu names on the menu bar File Project Geometry Water Calculation Results Tools Window Help Figure 2 3 MWell menu bar The menus contain the following functions File Standard Windows options for opening and saving files as well as several MWell options for exporting and printing active windows and reports Project Options for defining or not sheet piling defining properties and viewing the input file section 4 1 Geometry Options for adding or editing soil profile i e clusters of aquitards and aquifers wells position and discharge sheet pile walls the top view area and mesh for contouring section 4 2 Water Input of water parameters section 4 3 Calculation Options for editing the points and time grid for ti
57. use button must be clicked on a random position in the contour field The View Preferences dialog box pops up and can be selected This refers automatically to the Contour Plot Options in the Project Properties Menu Legends Rulers Labels and Label Interval can be edited Also the color presentation shades visible or isolines lines visible can be switched on and off The color palette and label can be changed here The contouring interval can also be found in the lines above the chart in the Contour Plot field The contour range defines the number of color areas or isolines to be drawn The options are to use an automatic division in steps or to have it manually selected by the user In the last case the user must define a minimum and maximum level for the contouring and a step value There are several print options Below the menu bar two icons are present for printing and previewing that serve as speed buttons The print options can also be found in the File menu as File Print preview active window or File Print active window where the user defined printer setting can be arranged 36 of 49 Deltares View Results Export of graphical results to other programs can be done by using the menu options File Copy active window to clipboard or File Export active window where several kinds of files can be saved on the computer in formats wmf dxf etc The settings of the frame can be changed by using File Page Setup There the lay out of pages
58. within the MWell program This is a numerical process where numerical integration is needed This action is time consuming It is speeded up through the intro duction of an analytical approximation At the start of a computation the user may choose between the analytical approach and the numerical simulation The analytical approach is found to give a larger inaccuracy in the results 5 than the numerical approach 1 but still in most cases this might be good enough In the numerical approach if optionally selected by the user a value for the segment length amplifier can be set The smaller the sheet pile elements the more accurate the result of computation will be However a large amount of elements slows down the calculation process Therefore within the program an optimum is realized by subdividing the sheet pile segments Deltares 41 of 49 MWell User Manual This is achieved by a method of segment partitioning and amplification Locations where a small segment length is required i e near wells located at short distance from the sheet pile wall are recognized in MWell With larger distance from such points the subdivisions of the segment lengths are amplified The distance between the wells and the sheet pile walls affects the accuracy of the outcome Therefore the segment length close to a well is restricted according to the distance of the well from the sheet pile wall By implication positioning of wells close to the sheet
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