各向异性砂土K0试验研究

静止土压力系数K0是岩土工程分析计算中的重要力学参数之一。实际工程中墙后填土由于碾压都具有不同程度的各向异性。制备了不同沉积方向的砂土试样，通过三轴排水剪切试验研究了砂土的各向异性。在研制应变路径试验设备的基础上给出了静止土压力系数的测量方法，研究了不同沉积方向对于K0的影响，并将试验测得的静止土压力系数与Jaky公式以及土压力离心模型试验结果进行了对比，离心模型试验结果与材料单元试验结果一致，证明了测量方法的有效性及结果的正确性。研究结果表明，各向异性条件下的K0值比各向同性时明显偏大。

Experimental study of K0 of anisotropic sand

The coefficient of earth pressure at rest, i.e. K0 is one of the important mechanical parameters for analysis and computation in geotechnical engineering. In engineering practice, the mechanical behavior of backfill is anisotropic due to compaction. Some sand samples with different sedimentation directions are made. Anisotropy of sand is revealed by triaxial drained tests where bedding planes of the samples are horizontal and vertical respectively. Measurement method of K0 is given on the basis of development of strain path test machine. The effect of different sedimentation directions on the K0 value is investigated. And comparison is made among test results, the results predicted by Jaky’s equation and those got by centrifuge model tests. The effectiveness and accuracy of the test method of K0 is confirmed by the centrifuge model tests of earth pressure. The results show that the neglect of the effect of anisotropy will underestimate K0 value and make the earth pressure underestimated.