多量程土压力盒标定工装及试验研究

为了精确获取土压力测试数据，总结了土压力盒标定工装研究现状，指出了现有标定工装存在通用性问题. 针对多量程土压力盒标定，采用ABAQUS有限元软件建立了仿真模型，研究了承压板、标定桶的尺寸对土压力盒承压面受力的影响，基于提取的数据进行合理性分析，确定了标定试验工装的参数及尺寸，并采用重新装砂、单次加卸载和不扰动砂、重复完全加卸载两种方案分别对量程为0.3、0.6、1.0、2.0 MPa的土压力盒进行了标定对比试验. 结果表明:试验数据相关系数R2大于0.90，线性关联性较强，且试验组、对照组K值重复性较好，本次制定的工装可靠，试验数据正确合理，能够很好地标定多量程土压力盒；从重复加载、滞回性上分析，不扰动砂、重复完全加卸载方案数据相对稳定，建议该方案作为标定试验方案；砂标K₁值小于厂标K₂值，电阻应变式土压力盒在使用之前均要结合工程实际环境重新进行标定试验，以使参数更精确. 

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.