Research on Calibration Equipment for Multi-Range Earth Pressure Cell and Calibration Experimentation

The general problems encountered in obtaining accurate soil pressure test-data are determined by performing a literature review of the research on calibration devices for soil pressure cells. Then, a finite element simulation for the calibration of multi-range soil pressure cell equipment is performed using ABAQUS, revealing how the sizes of bearing plates and calibration barrels affect the bearing surface stresses of the soil pressure cells. The extracted data are used to inform the performance of a rationality analysis to determine the key parameters and sizes of the relevant calibration equipment. On this basis, the single-load-recreating-the-sample scheme, and the cyclic-load-without-disturbing-sand scheme, are adopted to carry out the calibration on four soil pressure cells whose measured pressure ranges are 0.3, 0.6, 1.0 MPa, and 2.0 MPa. The results show that the correlation coefficient of the experimental data, R², is greater than 0.90, showing strong linear correlation. The K values of both the experimental group and the control group have good repeatability, which means the test data is correct and reasonable, and the calibration equipment is reliable. As such, multi-range soil pressure cells can be calibrated effectively using this equipment. Analyzing the repeated loading and hysteresis loops indicates that the data from the cyclic-load-without-disturbing-sand scheme is relatively stable, supporting the recommendation of this scheme as the calibration test program. The test value K₁ in the calibration of sandy soil is less than the factory value of K₂; in order to improve the accuracy of the parameters, soil pressure cells of the resistance strain type should undergo a calibration test appropriate to their intended practical environment before use.