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E1001A-171107                                                                                                                                           

26 

Where:  

-    L is the length of the measuring cell (given in table above) 

-  D is the inside diameter of the calibration tube 

-  Vi  is  the  resulting  intercept  of  a  straight  line  extension  of  the  volume 

calibration curve. Refer to the ASTM D4719 standard for more details. 

 

 

Vi Determination 

The  limit  pressure  P

L

  corresponds  theoretically  to  the  pressure  required  to  double  the 

volume  of  the  initial  cavity.    The  total  injected  volume  is  then  equal  to  V

o

  plus  twice  the 

volume  injected  in  order  that  the  probe  contacts  the  walls  of  the  borehole.    The 
recommended  procedure  to  obtain  P

L

  is  to  estimate  it  on  the  manually-extended 

pressuremeter curve.  

Note that Roctest offers a spreadsheet TEXAMCOMPANION for data reduction. You may 
contact us to get a free copy.  

Reading interpretation can be done referring to the following documents: 

  ASTM D4719-07 Standard Test for Pressuremeter Testing in Soils 

 

‘The Pressuremeter’, Balkema, Briaud, J.-L., 1992 

 

‘Geotechnical Engineering: Unsaturated and Saturated Soils’, Wiley, Briaud, J.-L., 
2013 

 

‘Interpretation and Application of the Pressuremeter Test Results’, Soil-Sol D.60 

 

 

 

Vi 

Содержание TEXAM

Страница 1: ... potentially dangerous The Company makes no warranty as to the information furnished in this manual and assumes no liability for damages resulting from the installation or use of this product The information herein is subject to change without notification Tel 1 450 465 1113 1 877 ROCTEST USA Canada 33 1 64 06 40 80 Europe www roctest com www telemac com E1001A 171107 ...

Страница 2: ...3 Saturating the tubing probe assembly 16 6 CALIBRATION 16 6 1 Calibration for pressure correction 16 6 2 Calibration for volume correction 17 7 TEST EXECUTION 17 7 1 Making of the borehole 17 7 2 Initial readings 17 7 3 Strain controlled test 18 7 4 Stress controlled test 19 8 PROBE DISASSEMBLY AND ASSEMBLY 19 9 TRANSPORT 22 10 LIMITATIONS OF USE 22 10 1 Cold temperature 22 10 2 Soft material 22 ...

Страница 3: ...g the method that will produce the least disturbance to the test material with the tightest hole possible Once in place the probe is submitted to equal increments of increasing volume or pressure and the pressure volume data is plotted The graph below shows a typical curve obtained from a pressuremeter test The curve can be divided into three parts The first portion of the curve corresponds to the...

Страница 4: ...gh precision digital gauge mounted on a quick coupler and vent valve assembly e A 70 mm diameter probe or a 44 mm probe for use in a slotted casing The probe consists of a cylindrical metallic body covered with an inflatable rubber sheath protected or not with metallic strips f The high pressure black tubing also called Tecalan g A steel pipe for calibrating the probe not included h One Readout Bo...

Страница 5: ...andle b Screw jack actuator c Hexagonal Nut 4 d Washer 4 e Knurled Nut f 8 32 Flat Head Screw 4 g Volume Counter optional h Handle i Support Column 4 j Control Box Please see the appendix for additional components descriptions a b c d e f g h i j ...

Страница 6: ...r 5 Make sure volume and pressure transducers read properly Refer to section below on how to use the DP Box Note that volume readings obtained from the electrical sensor must prevail over the one displayed by the mechanical volume counter See section 13 for more details 6 Place the small crank handle h on the crank shaft of the actuator Turn the handle counter clockwise to bring the actuator screw...

Страница 7: ...test data These test data can be uploaded to a laptop via USB communication The DP Box comes in a convenient water proof enclosure and is fitted with two 12 V rechargeable batteries providing over 8 hours of autonomy in normal conditions The DP Box also comes with cable universal AC wall plug with US Euro adapter adapter cable for car lighter and for external battery The battery can be charged eve...

Страница 8: ...Application should be installed on a Tablet This application can be downloaded from Roctest web site 4 3 CONNECTING AND TURNING ON THE DP BOX Connect the electrical cable of the testing equipment to the DP Box Turn on the DP Box The LED on the front panel will then blink Turn on the Tablet Go in the Tablet Setup and make sure that the DP Box is available and paired with the Tablet Set up the Table...

Страница 9: ...DP Box and the Tablet which will be confirmed when the DP box LED will blink quicker see below for more information 4 4 USING THE DP BOX READER APPS The DP Box Application allows configuring the unit to read and to log the data and to review the results 4 4 1 MAIN MENU Main menu of the applications includes the following elements ...

Страница 10: ...DP BOX which takes a few seconds The name of the DP Box will then replace the Scanning inscription Used for configuring and running a testing session Used for configuring and running a calibration session Used for viewing readings Used for Establishing Bluetooth communication Selecting an Instrument Type TEXAM DMP PROBEX Selecting the units Setting Date and Time And for Quick Readings of the Senso...

Страница 11: ...ent Add a New Instrument and Select the Type of instrument TEXAM and enter the serial number appearing on the control unit e g 001A17003 The DP Box name should appear here Select for additional functions Editing deleting instruments ...

Страница 12: ...cessary Go in Quick Readings and press the green icon for reading the sensors Two types of calibrations can be done one with the probe unconfined Pressure Loss Calibration and one with the probe confined Volume Loss Calibration See next section for more details For configuring a calibration go to Calibration and Select the type of calibration Select a probe by giving a serial number generally indi...

Страница 13: ...itial readings the operator should press Start for starting the timer Readings will be recorded when timer gets to 0 second Then the operator can increase the volume or pressure to the first step and then press Start for starting the timer and so on until completing the test When the calibration or test is over press on For starting the timer Readings are automatically recorded each time timer get...

Страница 14: ... imperative to maintain the ends of the tubings submerged during the saturation Otherwise air will enter the TEXAMe You may tape the tubings to the bottle for ensuring that 3 Set valve No 6 on FILL 4 Turn the small crank handle clockwise to bring the cylinder piston to its uppermost position corresponding to about 1732 cc on the counter The uppermost position is reached when resistance is felt whe...

Страница 15: ...wise to expel any air that may have accumulated at the top of the cylinder During this operation watch closely to see that all entrapped air is evacuated and only bubble free water is flowing into the bottle by the tubing connected on the port No 1 10 Return the instrument to the vertical and disconnect tubing from the port No 1 11 Connect the hose to port No 3 12 Turn the crank until water comes ...

Страница 16: ... is more than 15 cc the instrument is not completely saturated Repeat the saturation procedure described in steps 4 1 7 to step 4 1 15 The instrument is completely saturated when the volume indicates less than 15 cc at 2 500 kPa Having determined that the instrument is completely saturated rotate the large crank handle until the pressure reaches 10 000 kPa The pressure should stabilize after 2 min...

Страница 17: ...n tubing from port No 1 Refill the cylinder by placing valve No 6 on FILL and returning the piston to its lowermost position Wait a few seconds 6 Repeat step 4 2 as a final check on the saturation of the unit 7 Disconnect the tubing from port No 4 8 The instrument is ready to be calibrated The instrument probe and tubing can be saturated in advance and transported to the site ready for testing 6 C...

Страница 18: ... least 5 seconds prior to recording readings Record volume and pressure after 60 seconds 5 Install the large crank handle 6 Increase pressure by another 500 kPa step and take readings after 60 seconds as described above Repeat this procedure to 6 000 kPa 7 When tests in very hard material are to be done where it is expected to exceed 6 000 kPa during the test follow the same calibration procedure ...

Страница 19: ...ts typically for determining the limit pressure with a satisfactory accuracy typically between 1000 to 1200 cc for an NL probe b or when risk of bursting the probe is high see chart at the end of this manual 3 It is possible and suggested to carry on an unload reload cycle in the pseudo elastic zone i e between Pf creep pressure and Po in situ horizontal earth pressure This cycle can be performed ...

Страница 20: ...an be estimated with the following relation Pressure step bar N blow per foot 20 Example if N 17 start with a 0 5 bar pressure increment Check delta V 60 sec 30 sec cc at each step in order to determine if you are in the pseudo elastic zone or in the yielding zone The first zone is characterized by rather constant delta V The second zone is characterized by increasing delta V If you still are in t...

Страница 21: ...tly fixed to the bench vice 7 Do not grease the o ring Slide a metallic sheath on the probe s body Make sure the electrical tape on each end of the sheath has been removed 8 Place the second o rind at the other end of the probe Make sure the sheath is centered and that both o rings are at their place 9 Make sure that the metallic strips are not twisted 10 Put hose clamps over the sheath Pay attent...

Страница 22: ...t the brass knurled nut in place and screw it This will push the yellow ring inward Proceed until three threads can be seen 14 Free the probe from the vice and from the vice adaptor then reinstall it on the vice but on its other end 15 Make sure that the metallic strips are still straight Put the yellow ring and knurled nut on this end of the probe 16 Using a strap wrench keep on tightening the kn...

Страница 23: ...w temperatures will significantly increase viscosity of the liquid which means that time required for inflating and deflating the probe will significantly increase too A 50 50 solution of water ethylene glycol by volume will allow using the equipment at about 25 C a 70 30 solution can be used down to about 10 C It is very important to flush the unit with clean water as often as possible to protect...

Страница 24: ... for performing tests at great depth over 100 m provided the borehole is filled with fluid 11 RECOMMENDATIONS Do not wait until the last minute to verify and calibrate the equipment On site keep different sizes of drilling bits and two complete probes to speed up testing On remote sites bring a bench vise for membrane replacement Check data as test proceeds The shelf life of sheaths is 2 years The...

Страница 25: ...er saturating the pressuremeter put it under pressure up to 10 000 kPa and check for leaks If the filter leaks tighten up the nuts or put a new filter assembly 12 3 SPLICING THE TECALAN TUBING 1 Cut the tubing at a right angle cleanly 2 Install a socket in a vice Do not overtighten do not misshape the socket 3 Screw the tubing into the socket thoroughly by rotating counter clockwise Then unscrew o...

Страница 26: ...ith a volume correction factor c given by the following equation c a b The correction factor a is calculated from the linear part of the curve of the calibration in the steel tube The b parameter takes into account the expansion of the steel tube during the calibration and is calculated with following equation b 2V r e 1 m Em e Where V Volume of the probe when in contact with the metallic calibrat...

Страница 27: ...to Vo plus twice the volume injected in order that the probe contacts the walls of the borehole The recommended procedure to obtain PL is to estimate it on the manually extended pressuremeter curve Note that Roctest offers a spreadsheet TEXAMCOMPANION for data reduction You may contact us to get a free copy Reading interpretation can be done referring to the following documents ASTM D4719 07 Stand...

Страница 28: ...e two sides of the piston 7 At each constant pressure step record the volume readings at regular intervals 8 To return the piston to its initial position it is necessary to couple the actuator screw to the piston shaft using the knurled nut Please note that pressuremeter equipped with a creep test kit should be assembled as shown on the following picture Volume readings of the electrical sensor vs...

Страница 29: ...te PMT probe l Vulcolan steel ring F Probe shoe m Vulcolan collar G Probe to bench vice adaptor n Metallic sheath Tecalan Tubing and Connectors a Tecalan Tubing Assembly b Tecalan Connector 10 1001001145 including a Socket b and a Coupling c c d Adaptor from probe to Tecalan e Ferrule 05 R17LA1111000 f Modified Nut 10 mm 10 1001001149 g Male quick connect h Elbow Connector optional i Union for spl...

Страница 30: ...E1001A 171107 29 Typical Corrected Test Data ...

Страница 31: ...E1001A 171107 30 Optional Pressure Gauge Operation For more info see www ashcroft com ...

Страница 32: ... contact below 400 cc uniform borehole Unless otherwise specified the test is terminated when sufficient data has been accumulated for the intended purposed of the test typically between 1000 and 1200 cc for an NL probe or before reaching high risks of bursting the probe as indicated on this chart Note that the probe may burst at lower pressures depending among others on how the sheath was assembl...

Страница 33: ...essure Units Variations Units Volume cc Pressure Units Variations Units Soil Description ________________________________________________Temperature ___________ Pressuremeter Type _________________________ Notes ____________________________________ _____________________________________________________________ Operator _______________ PRESSUREMETER TEST DATA SHEET ...

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