微风化红层砂泥岩动三轴力学特性试验研究

EXPERIMENTAL STUDY ON DYNAMIC TRIAXIAL MECHANICAL PROPERTIES OF SAND AND MUDSTONE IN BREEZY RED BED

  • 摘要: 红层广泛分布于四川盆地及周边地区,考虑该区域地震及工程施工扰动影响,本文针对粉砂质泥岩、泥质粉砂岩和细砂岩3种典型微风化红层岩石,开展了中等应变率条件下的动三轴压缩试验,揭示了其动力学特性的围压效应和应变率效应。3种岩石的动力学参数均具有明显的围压和应变率敏感性,动强度和动弹性模量均随应变率和围压增大而增大,而动泊松比随着应变率增大而减小,随着围压增大而增大;基于二元非线性回归分析,提出了试验条件范围内3种岩石的动强度预测模型,以期为工程应用提供参考。

     

    Abstract: Red beds are widely distributed in Sichuan Basin and its surrounding areas. Affected by earthquakes and engineering construction disturbances in this area, the rock dynamic characteristics are the most concerned factors in engineering construction. In this paper, a series of dynamic triaxial compression tests have been carried out on three typical breezy red bed rocks, namely silty mudstone, argillaceous siltstone and fine sandstone, under the medium strain rate conditions. The confining pressure effect and strain rate effect of their dynamic characteristics were revealed. The dynamic strength, dynamic elastic modulus and dynamic Poisson's ratio of the three kinds of rocks are obviously sensitive to both the confining pressure and strain rate. The dynamic strength and dynamic elastic modulus increase with the increase of strain rate and confining pressure, while the dynamic Poisson's ratio decreases with the increase of strain rate and increases with the increase of confining pressure. Based on binary nonlinear regression analysis, the dynamic strength prediction models of three kinds of rocks in the range of test conditions were proposed, in order to provide reference for engineering applications.

     

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