论文部分内容阅读
土工模型试验和现场试验中常采用膜式土压力盒作为压力测试元件,即通过测量膜的变形(挠曲)量获取压力值。膜式土压力盒作为埋入介质内部的测试元件,由于土压力盒与岩土介质的刚度差,测试中受到由差异变形导致的岩土介质土拱效应的影响,特别是模型试验的应力历史也会产生不同程度的土拱效应影响。针对桩承式路堤多陷阱门模型试验中的加卸载条件,采用相同的试验用砂在相同的相对密度条件下进行了1组加载标定和4组不同填料高度下的卸荷标定试验。结果显示,加载曲线线性较好,而卸载曲线可采用指数曲线来进行拟合。将获取的标定系数应用于桩承式路堤多陷阱门模型试验当中,发现填料填筑过程中采用砂标系数处理得到的平均土压力值与路堤自重应力较为吻合。在陷阱门下沉模拟桩间土下沉过程中,分别采用砂标加载系数和卸荷系数处理土压力数据,与实际情况能够较好的吻合。
Membrane earth pressure boxes are often used as pressure test elements in geotechnical model tests and field tests, ie the pressure values are obtained by measuring the amount of deformation (deflection) of the membrane. As the test element embedded in the medium, the film earth pressure box is affected by the soil arching effect caused by the differential deformation due to the difference of the stiffness between the earth pressure box and the geotechnical medium, especially the stress history of the model test Will also produce different degrees of soil arching effect. Aiming at the loading and unloading conditions in the multi-trap door model test of pile-supported embankment, the same test sand was used to calibrate the unloading calibration under the same relative density conditions and under four different packing heights. The results show that the loading curve is better linearly, while the unloading curve can be fitted by exponential curve. The obtained calibration coefficient is applied to the multi-trap door model test of pile-supported embankment. It is found that the average earth pressure value obtained by sand standard coefficient processing is in good agreement with the self-weight stress of embankment. In the course of sinking subsidence of trap door, the soil pressure data were processed by sand load coefficient and unloading coefficient respectively, which is in good agreement with the actual situation.