Menard Presuremeter test

 Menard presuremeter test is an in situ stress controlled loading test performed on the wall of the borehole using cylindrical probe which can expand radially.

From the readings, stress strain curve can be obtained which yields : 

a. the presuremeter modulus 

b. the creep presure (yields presure)

c. the limit presure (failure presure)

Figure A.6.1 shows schematiic diagram of Menard presuremeter test and typical test curves 

1.2 Equipment 

(1) The Monitoring Unit 

Equiped with device to preciesly regulate the presure applied to the probe and read is volume change with presure increment and time. A gas cylinder provides the pressure source. It  includes a 800 cm3 volumeter with sight of tube, a main pressure a regulator , a differential presure regulator, presure gauge 0-2.5 and 0-6 Mpa for the measuring and guard cell (0.06 and 10 Mpa as option for soft soil and weak rock test) and the necesary valves and coupling. 

(2) The palstic tubing 

This coaxial or twin tubbing , flexible and of high resistance, conects the probe to the monitoring box with minimum deformmation. 

(3) The 3-Cell Probe

It includes a central measuring cell, filled with water . Its Volume change are read on the monitoring box volumeter. The probe is totally protected by rubber cover which is inflated by gas to form the 2 guard cell. Pressure applied ti the borehole walls are kept constant along the 3 cells through the differential pressure regulator to ensure a true cylindrical deformation along measuring cell. 

1.3 Test Procedure 

The borehole drilled so as to minimize wall disturbance and keep cavity diameter compatible with the probe size. The probe is lowered into the borehole to the required test depth and the pressure is applied by equal increments. Presure and volume readings are taken on the monitoring box.

In graveely soils under water table where the borehole would cave-in, the probe can be inserted in specially fitteds probes can also be part of string of pipes to be forced into soft soils, sometimes together with a static cone penetration device.