制样方法对初始各向异性砂土三轴剪切力学特性 的影响研究 1)

INFLUENCE OF SAMPLE PREPARATION TECHNOLOGY ON SHEAR BEHAVIOR OF INHERENT ANISOTROPIC SAND IN TRIAXIAL TESTS 1)

  • 摘要: 基于砂土颗粒的毛细效应特性和冻融试验原理,提出一种砂土试样制备方法,能够在0°~90°范围内任意选取沉积方向,且适用于不同颗粒级配的试样。在中围压条件下进行三轴固结排水剪切试验,研究结果表明,毛细效应、冻融相结合的制样方法能够减缓压缩剪切试验的应力-应变关系增长速度,降低试样的抗剪峰值强度,对残余强度的影响相对较弱。在其他应力路径条件下,例如拉伸、减压压缩、等应力压缩等试验中,可以不考虑装样方法的影响。建议的制样方法能够合理应用到砂土初始各向异性的研究工作中。

     

    Abstract: Based on the capillary effect and using the freeze thawing method for the sand grain, a sample preparation is suggested to make the sand sample with an arbitrarily sedimentary direction in the range of 0°~90° for any grain composition. A series of triaxial compression shearing tests are performed under a medium confining pressure, the results show that the preparation method combined with the moist sampling and the freeze thawing has a significant influence on the shearing behavior of the sand. With the method, the developing speed of the relation between stress and strain will be decreased, and the ultimate shearing strength will be lowered, but with little influence on the residual shearing strength. Under other stress path conditions of the triaxial test, such as the triaxial tension, the reduced triaxial compression and the triaxial isostress compression, the sample preparation has little influence on the results. The suggested sample preparation method is applicable for the experimental study of the sand inherent anisotropy behavior.

     

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