EXPERIMENTAL STUDY ON TEST RESULTS OF EARTH PRESSURE CELLS BURIED IN FINE SAND WITH DIFFERENT MOISTURE CONTENT UNDER THE INFLUENCE OF TEMPERATURE¹⁾

In the long-term engineering monitoring, the measurement accuracy of the earth pressure cell is easily affected by the temperature change of the surrounding soil. In order to improve the reliability of the measurement of the earth pressure, a few resistance strain type miniature earth pressure cells were embedded in a calibration bucket filled with fine sand with different moisture content, and a freeze-thaw cycle tank was used to simulate the temperature change environment. Multiple factors on the measurement results of the earth pressure cell were systematically studied with cycling temperature. Through experimental research, it is found that during a single freeze-thaw process where the temperature of the sand in the calibration bucket decreases from 20^\circC to 0^\circC and then rises to 20^\circC, the temperature has a greater influence on the measured pressure value of the earth pressure cell, and the temperature calibration coefficient is negative. The moisture content of fine sand has a relatively weak influence on the temperature calibration coefficient of the earth pressure cell. The use of a smaller-range earth pressure cell and the increase of the load on the upper part of the fine sand will increase the temperature sensitivity of the earth pressure cell. As the number of freeze-thaw cycles increases, the measured value of the earth pressure cell will be lost.