确定岩石动、静力剪切强度的方法
Methods of Determining Shear Strength of Rocks at Dynamic or Static Loading
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摘要: 本文探讨了确定岩石动、静力剪切强度的六种试验方法,并用这些方法,系统地研究了花岗岩、大理岩和砂岩的剪切强度。同时得出:①岩石的剪切强度随着加载速率的提高而明显增加(即动力剪切强度高于静力剪切强度)和随剪切面上正应力的增加而增加;②砂岩受400kg/cm2围压作用时剪切强度会出现一个由增加变为减少的转变点,即砂岩由脆性变为柔性的转变点,当围压低于此值时,砂岩的剪切强度随围压的增加而提高;当围压高于此值时,其剪切强度随围压的增加而降低等结果。笔者还建议使用简易的冲剪法去确定岩石的动、静力剪切强度。Abstract: Six test methods for determining dynamic or static shear strength of rocks are described in this peper. The shear strength of granite, marble, and sandstone have been systematically studied by means of these methods and the following results are obtained: 1 ) Shear strength of rocks clearly increases with the increase of loading rate, i.e. dynamic shear strength off rocks is higher than static shear strength, and shear strength of rocks increases with the increase of normal stress at the shear plane of specimens. 2) The value 400 kg/cm2 of confining pressure is a brittleness-ductility transference point for sandstone, i. e. the shear strength of sandstone increases with confining pressure going up when it is below 400 kg/cm2, and the shear strength of sandstone decreases with the increase of confining pressure when it is above 400 kg/cm2.The simple punch shear test method is recommended to determine static or dynamic shear strength of rocks.