含水率对非饱和钙质砂动力特性影响的试验研究

使用经过系统标定的霍普金森压杆试验装置对不同含水率钙质砂进行了在准一维应变条件下的动态压缩试验，试样的平均应变率为209～1 137 s⁻¹。试验结果表明：半导体应变片灵敏系数和压杆弥散关系的标定对试验结果的准确性具有重要影响；当钙质砂应变小于0.025时潮湿试样的切向模量高于干燥试样，而在应变大于0.025时则相反；潮湿钙质砂的切线模量随含水率的增加先减后增。通过分析非饱和钙质砂在锁变后其轴向应力应变曲线及侧压力系数的变化规律，提出了非饱和钙质砂锁变现象的模型。

Experimental study on dynamic compression of unsaturated calcareous sand

The dynamic compression tests of calcareous sands with different moisture contents under quasi-one-dimensional strain conditions were carried out using a calibrated SHPB system in the average strain rate ranging from 209 s−1 to 1137 s−1. The test results show that the calibration of the sensitivity coefficient of the semiconductor strain gauge and the dispersion of the pressure bar have a significant influence on the accuracy of the test results. When the strain of the calcareous sand is below 0.025, the tangential modulus of moist calcareous sand is higher than that of dry sand, but the opposite is true when the strain is above 0.025. The tangential modulus of moist samples decreases first and then increases with the increase of the water content. By analyzing the variation of axial stress-strain curve and lateral pressure coefficient of unsaturated calcareous sand after lock-in phenomenon, a model of the phenomenon of unsaturated calcareous sand is proposed.