User manual
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1. BIMBAR INFLATABLE PACKERS FPT Issue March 2008 Instru 24 Boulevard Initialis 7000 Mons BELGIUM T l 32 0 65 346000 Fax 32 0 65 346020 E mail info geopro be Website www geopro be Test Each inflatable element is tested with water in a test bench After assembly the tightness of each complete packer isalso tested A test certificate is supplied with each order Safety and guarantee Our packers are guaranteed free from any defect in material and workmanship Our guarantee is limited to the repair or replacement of any defective product or parts thereof This guarantee is void if the products are used in other circumstances than those described in ourtechnical sheets The decision of our technical department is final Please contact us for additional information Consdering the nature of equipement working under pressure users should be aware of the dangers and take the necessary precautions relating to the safety of their employees Our respongbility ends with our guarantee of good manufacture forthe material designed and made according to engineering rulesand techniques available at the time of manfacture Bimbarinflatable packers Instructions for use Geopro Bimbar inflatable packers are frequently used for grout injection and other geotechnical applications for structural reinforcement and or water sealing of deep foundations tunnels dams and mines The two main methods for grouting2. HAND PUMP l i N 5 TO PACKER 7 figure 4 Remarks The pressure gauge cannot be accidentally isoled from the packer and so always indicates the packer pressure The pressure source is independently isolated from the packer This is of great importance with gas regulator since they can easely be set at very high pressures or not be properly shut down In fact the temptation is to leave the regulated gas connected to the packer at pressure which may lead to packer over expansion and sub sequent failure The vent valve ensuresthat the packercan be safely deflated Being small self contained and portable if provided with suitable hose lengths the gauge set can be moved to the most convenient location to control and monitor the packer during inflation and grouting operations Cleary all components used in the inflation control system must be adequate pressure rating In the case of gas inflation if operating deep in a water filled hole the surface gas pressure may easely be over 70 bar and adequate precautions are required The pressure gauge should be chosen such that the maximum inflation pressure lies in the middle third of the gauge s scale Pressure gauges are delicate instruments that require careful treatment and regularcalibration to ensure their reliable operation 4 Inflating the packer Once the packer size has been chosen along with a Bimbarinflatable packers Inst
3. relatively very short time This characteristic takes some time to getting used to and operators should be encouraged to use the tral inflations to accustom themselvesto the pressure volumes and times involved 5 Deploying the packer The usual deployment methods are via a rigid pipe ora hose The later is quicker but provides limited depth control no packer hold down capacity and limited support for inflation tubes It s also depth limited by the self supporting capacity of the hose and it sconnection to the packer for which reason a safety wire is sometimes used along with the hose Depth limitations may also be due to the handling capacity of the hose raising and lowering system which is frequently manual Using a rigid pipe for running the packers offers good depth control good support for inflation tubes and some hold down capacity However it generally requires a mechanized system drill ig or crane to handle the rods due to their length and weigth and thus is much dower and more cumbersome Page 5 6 Packer damage and service life Packer damage during grouting operations is generally due to one of the following reasons 1 Over expansion caused by inflating in too large borehole or a washed out section of the hole or occasionally in a yielding soil such as weak clay If the operator expects such geology water is ecommended to inflate the packerso that volume of water requested to inflate the packercan be monit
4. 0 190 210 230 250 2 370 78 290 3 310 370 Table 1 Borehole diameter mm Figure 1 Packerinflated with gasat too low pressure Page 2 Under no circumstances should oxygen be used asit may cause explosive failure of the packer The operatorshould alwayscheckand monitor carefully the inflation pressure when gas is used to inflate the packer On the other hand the deflation ability of the water inflated packermust be carefully checked before use b Inflation with gas Gas inflation pressure is of critical importance and must be carefully calculated and monitored during grouting operations to avoid premature damage and destruction of the packer For any particular application the minimum inflation pressure required in unit of bar as read on the surface pressure gauge canbe calculated as follows Min Gas inflation pressure pressure to inflate to hole diameter sealing pressure max grout pressure Note that the maximum grouting pressure is the grouting pressure below the packer not the surface pressure at the gauge of the pump It is calculated as follows Max grout pressure depth of the packer m 10 x S G of grout surface grouting pressure column of water above the packer m 10 The pressure required to inflate the packer up to the hole diameteris given by the inflation curves but canbe estimated in the field before starting grouting operations To estimate the
5. S upto 10mm 2I B Double packers DP i i I Deez em COO SSID IN 28 up to 42mm L Injection msi ds Double packers DP T 56 up to 102mm L Test Z Double packers DP iii L Pee xs rm O Ds pP How to order PILI J G L Diameter mm S SP or DP Dilatable element Type A or WIP Injection zone length mm OrTest zone Length mm Example Double packer 42 Element length 300mm A Type Injection zone 500mm LJ alle el Ce TIL bel Le LL Le PILI Lel Le 42 DP 300 21 500 Geopro isconstantly improving its products and therefore reserves the rigth to change design materials specifications without notice Bimbarinflatable packers Instructions for use Page 7 Geopro Inflation adapters for packers Rilsan Inflation Hose OD 1D 6 3mm UA6 OD ID 8 3 4mm RIH 48 Retrievable Fitting LI Egret ES Fitting IN Body COMPRESSION FITTING j G1 4 BSPT Converting of inches to millimetres Bimbarinflatable packers Instructions for use Page 8 Geopro Differenttypesofpackers Internal inflation tube Sliding end Fixed end Extemal inflation hose T TZ Zi ae 8 Fixed end Fixed end Ne J u TE Re Bimbarinflatable packers Instructions for use Page 9 24 Boulevard Initialis 7000 Mons BELGIUM T l 32 0 65 346000 Fax 32 0 65 346020 E mail in
6. able clearance between the packer and the borehole unless very high working pressure is requested 2 Inflation fluid Generalities A major consideration is the choice of inflation fluid Most inflatable packer manufacturers recommend inflation with water for grouting applications whenever possble Generally the only time it s not possible is in a dry hole or where the water level is too low In these circumstances the column of water in the inflation line is too great to allow complete deflation of the packer Even then use of special deflation valves usually requiring two inflation lines makes use of water inflation possible We will describe laterthe functionning of these deflation valves Water inflation is usually prefered because waterinflated packer after establishing an initial seal will remain inflated up to the burst pressure of the packer owing to the incompressbility of the water In contrat a gas inflated packercan only provide a seal if the gas pressure ismaintained at a level above the sum of the sealing and grouting pressures Leaks relaxation soil movement excess grouting pressure etc can all lead to bypass of the inflated packer without the operators knowledge After some time and hardening of the cement the packer will become difficult or impossible to retrieve Moreover quick pressure pulsation of the grout pump can also generate a packer movement in the borehole if it s inflated at a too low pr
7. are up stage grouting where the grout is injected into the ground below a single inflated packer and tube a manchettes grouting for which our double packers type ZA are usually requested to inject grout into a PVC pipe Whether using single or double packer both grouting methods rely on the use of inflatable packers for efficient and reliable sealing and reinforcement of the geological formations We will consider the general criteria of importance in selecting and using inflatable packers The target of this article isto provide advises to the operators to solve the most common problems met with inflatable packers At rest Inflated Single Packer Single Packer Bimbar inflatable packers Instructions for use Geopro BIMBAR INFLATABLE PACKERS PRODUCTS SYSTEMS AND SERVICE The Bimbar Inflatable Packers catalogue is available on our website www geopro be Double Packer Page 1 1 Differential pressure and sizes The range of Bimbar packers is available in 9 different diameters from 28mm up to 170mm OD These packers are reinforced with two spiraled layers of steel embedded into natural rubber One layer is spiraled clockwise and the other one is anticlockwise The two steel layers provide the resistance to the intemal and extemal pressure The maximum differential pressure decreases with the expansion of the packeraspertablel Do not use the packer at its maximum expansion and keep a reasonn
8. esure causing a fast destruction of the outer cover of the Bimbar rubber as the packer is not anchored propery See figure 1 In fact any liquid provide the same inflation benefits as water and in sub zero temperatures other water anti freeze solutions glycol must be used Where possible however water is the preferred liquid since it s non polluting readily available and will not damage the rubber Note Bimbar packers are made of natural rubberand are not compatible with oil inflation The major drawback with using water for inflation is that deflation is dower than when using gas and it may be more inconvenient to operate a manual inflation pump in some circumstances When gas inflation is chosen operators will use compressed air nitrogen or any neutral gas Bimbarinflatable packers Instructions for use Geopro Maximum working pressure bar In relation with borehole diameter mm 140 130 28 230 120 110 100 90 fe A 80 o 5 70 a 60 oa 50 amp 40 x 20 10 30 50 70 90 110 130 1 17 1 40 60 80 100 120 140 150 360 7 130 1 Borehole diameter mm 80130 70 je 2 6 o 5 50 a 40 a D D 30 5 5 20 mr es 140 160 180 200 220 240 26 2 150 17
9. fo geopro be Website www geopro be Bimbarinflatable packers Instructions for use
10. kers Instructions for use Geopro If static water level SWL is located above the packer the column of water above the packer in the borehole will help to deflate the packer Max setting depth m table 2 value Packer depth below water m Deflation valve principle If the setting depth of the packer is below the max setting depth and still to benefite the advantages of waterinflation a deflation valve can be used The deflation valve is connected onto the fixed end of the packer using the second inflation port It requires to run a second line To deflate the packer an air pressure is set through the second line and the water will escape through the holeslocated at the bottom of the deflation valve see figure 3 Inflation Line Second Line Ground Floor 1 A m a 4 a Water static a Level WSL j Deflation Valve Figure 3 Page 4 3 Inflation contol Regardless of the type of packer or the inflation method it is critically important to have an inflation system that provides sufficient control and monitoring functions The assembly shown in figure 4 or equivalent set up is consdered to be the minimum for safe efficient operations The system basically requires a pressure source an isolating valve a vent valve a pressure gauge suitable hose to connect to the packer and between the other items i _ or st eq peau e
11. ored and controlled 2 Outercoverof rubber cutting caused by any sharp object in the borehole eg end of casing or a casing joint or sharply fractured rock This problem becomes more critical in inclined or horizontal holes as rubber of the packer is in contact with the rock formation when run in or out Protection rings can be used under these circumstances on both sdes of the packer see figure 5 Sliding End Removable Ring Removable Ring oo 9 a Inflation Adapter Inflation Line figure 5 3 Over pressunzation Packers are rated for specific pressures in specific diameter holes and over pressunzation is caused by using packers too high pressure rating Always refer to manufacturer s diameter in relation with pressure rating charst before deciding on an inflation pressure 4 Moving a packer when it s still partially inflated can damage it either by excessive wear against the hole wall or by pulling the steel ends off the rubber either partially orcompletely 5 Grout contamination of a diding end packer mandrel can prevent the packer end from diding and ordamage the diding end seals Bimbarinflatable packers Instructions for use Geopro 6 Deterioration of the rubber in packers due to direct sunligth or high temperature conditions or solvents exposure Packers should always be stored in boxes to protect the rubberagainstU V 7 Inflating natural rubber packers with oil will cause exce
12. ructions for use Geopro suitable inflation fluid inflation control and monitoring system it s time to connect it all up and tral inflate the packer If gas inflating trial inflations should only be perfomed in a pipe of adequate thickness and with appropriate safety precautions If inflating with a fluid trial inflations may be performed free in air but are probably more usefully done ina pipe Trial inflation allows the operator to check for system performance and leaks Specifically the operator should be checking inflation pressure to fim contact with the test pipe wall and packerintegrity at the maximum pressure It is best to perform trial inflations with the full length of inflation tube that will be run in the hole to reach the maximum setting depth of the packer This allows the operateorto time inflation and deflation get a indication of pumping pressures during different stages of inflation and fora liquid inflated packer primes both the packer and the inflation tube The general charactenstics of packers whether inflated with liquid or gas is that the bulk of the inflation volume is placed into the packer at relatively low pressure and it is only the last little bit of volume that is placed at increasingly higher pressure Charting inflation pressure against time leads a curve showing low steady pressure increase over an extended period followed by a rapid pressure increase after wall contact is achieved in a
13. sealing pressure really a safety factor to assure adequate sealing a value of 15 of the maximum grouting pressure should be used asa tule of the thumb The RECOMMENDED gas inflation pressure minimum gas inflation pressure x 1 3 safety factor This safety factor is used to guarantee the anchoring of the packerin the borehole This value should be compared with the table giving the maximum working pressure in relation with borehole diameter and should be always inferior to the value found in the table 1 Bimbarinflatable packers Instructions for use Geopro Example see figure 2 Max grout pressure 70 10 x 1 3 20 50 10 24 1 bar Min gasinflation pressure 3 24 1 x 0 15 24 1 30 7 bar Recommended gasinflation pressure 30 7 x 1 3 40 bar Max working pressure table 1 80 bar OK Inflation Line QE sit Injection Line Ground Floor Water Static Level 4 WSL Packer 56mm Hole diameter 3 76mm Setting depth 70m WSL 20m Grout SG 1 3 Surface grout pressure 20bar Packer Setting Depth figure 2 Safety Another prime consideration with gas inflation isthe safety aspect of dealing with high pressure gas A gas inflated packeris basically a bomb and should be treated assuch If rupture it has potential to do lethal damage Under no circumstance should gas be used to test inflate packer in open air Test inflation should always be conducted using water for infla
14. ssive swelling and associated softening of the rubber 8 Long tem inflation with gas though rarely a criteria in grouting operations often cause rubber blistering and delamination after the packer is removed from the borehole The gas which has been absorbed into the rubberunder pressure willbe collected in pockets forming sometimes bubbles on the outercover of the packer 9 Cement by passof packerwhen used forlong grouting periods several hours in cracked or fractured rock formations Longer packers should be used in this case see figure 6 LONGER PACKER CEMENT BY PASS figure 6 7 CONCLUSIONS Assuming that the packers are well maintained and adequately tored between uses and if they are used in accordance with guidelines given in this manual then inflatable packers should provide long tem reliable service for grouting operations There is no intrinsic reason why tens or even hundreds of grouting operations may not be performed with a single packer When such service life is not realized it is frequently due to one ormore of the factors highlighted above It is hoped that this article will serve to remedy these problems and that with such knowledge available contractors will ensure that their operatos are appropriately trained Page 6 Geopro Single double packers and dilatable element Orderreferences Dilatable elements 28 up to 170mm Single packers SP 28 up to 42mm i
15. tion in a pipe and with adaquate protection to personnel against injury by projectiles ejected from the pipe should the packer fail Page 3 c Inflation with water Water is not compressible and therefore it doesn t provide the explosive effects of gas A water inflated packerwill react asa hydraulic seal Inner inflation and outer grouting pressures will equilibrate automatically and the control of the inflation pressure is much less critical The RECOMMENDED water inflation pressure Pressure to inflate to hole diameter sealing pressure maximum grout pressure packer setting depth m 10 Once again this water inflation pressure should be inferiorto the value given by table 1 On the otherhand the watercolumn located inside the inflation line will create a hydrostatic pressure and make the packer sometimes difficult or impossible to retrieve in vertical holes consider ten meter of depth 1 bar inflation pressure The hereunder table 2 shows the maximum setting depth of water inflated packer in function of borehole diameter assuming that the borehole isdry Borehole diameter mm 30 50 70 9 0 MO 120 130 150 170 190 60 65 70 75 80 Max setting depth m in a dry hole with water inflation 85 90 95 100 105 110 115 w Table 2 Bimbarinflatable pac
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