土压力传感器在硬土介质中的非线性响应分析

为掌握土压力传感器置于硬土介质中呈现的非线性响应特性，建立了传感器与土介质的相互作用模型，运用有限元分析了满足匹配误差稳定所需的传感器与土介质的模量比条件。进行了传感器的单体标定和级配碎石土介质标定试验，探讨了传感器非线性响应的主要影响因素。计算与试验表明，目前国内主流的双膜土压力传感器在量测硬土介质中的土压力时，由于模量偏小标定曲线非线性显著；土压力传感器单体标定曲线线性度较高且其模量基本稳定，表明土介质的模量变化是引起标定曲线非线性的主要因素；通过将传感器置于与使用环境相近的土介质中进行标定，并采用非线性修正可明显提高硬土介质中土压力量测的准确性。

Analysis of nonlinear response of soil pressure transducer in high-modulus soil

In order to grasp the nonlinear response characteristics of soil pressure transducer in high-modulus soil, based on the interaction of model of transducer with soil, the reasonable modulus ratio of transducer and soil medium was studied with FEM. And the main factors about nonlinear response of transducer was studied by monomer transducer calibration test and transducer calibration in graded broken stone medium. Based on the results of FEM and calibration test, some conclusions are drawn as follows. The modulus of domestic mainstream transducer is too low to satisfy the reasonable modulus ratio at present when used in high-modulus soil meadium, which leads to the significant nonlinear characteristics of calibration test curve. The monomer test curve is highly linear and the modulus of transducer is stable, which shows that the nonlinear characteristics of calibration test curve is mainly caused by the soil modulus’s change. The test precision can be significantly increased by calibrating the transducer in the same state soil as field test and correcting the calibration results nonlinearly.