METHOD TO AUTOMATICALLY MEASURE PORE AND SIDE PRESSURE UNDER CONDITIONS OF SOIL COMPRESSION Russian patent published in 2011 - IPC G01N3/08 E02D1/00 

FIELD: construction.

SUBSTANCE: method to measure pore and side pressure under conditions of soil compression includes the following stages: preparation of an odometer for tests with its subsequent connection to a back pressure unit and an automatic control unit. Underpressure of 15…30 kPa is pulled in the odometer chamber. With computer control, a motion sensor is used to monitor and measure value of a soil sample displacement, when its value reaches the value of the soil sample elevation, a step motor is switched off, fixing the soil sample in a working position inside a rubber shell. Air suction is closed, the working chamber is filled with degassed water from a reservoir. Upper and lower valves are opened in the back pressure unit, the back pressure value is pulled with an air compressor and monitored by the sensor in the reservoir, water is pushed at the top and bottom of the soil sample, the sensor is used to monitor pore pressure at the lower border of the sample. Steps of 15…30 kPa are used to increase the back pressure until full water saturation of the soil sample (S_r=92…95%), and when the measured pore pressure and the back pressure are equal, water saturation is stopped. Using the developed program, the soil is tested for compression with constant speed of axial deformation to the specified efficient strain. In process of tests full and efficient vertical and side strains are measured, as well as pore pressure and axial deformation.

EFFECT: increased accuracy of measurement of the soil pore and side pressure, expansion of research range, automation and increased efficiency of tests.

8 dwg, 5 tbl