结构面抗剪试验及强度参数影响因素分析

Shearing Test on Structural Planes and Influence Factors on Strength Parameters

结构面抗剪强度参数是岩体工程稳定性分析和设计的重要参数之一。选取煤岩和砂岩两种岩性的软弱结构面进行剪切试验,采用最小二乘法、点群中心法和可靠度分析法对试验结果进行了对比分析;并考虑结构面倾角θ对试验结果的影响,推导出抗剪强度参数粘聚力c和内摩擦角φ的修正公式。研究表明,当试验结果相关性较好时利用最小二乘法确定c和φ最为方便快捷,当试验数据离散程度较高时,可靠度分析法处理精度较高;结构面倾角θ会使实验得到的粘聚力c和内摩擦角φ比真实值偏小,倾角越大,偏离越大。当加工的试件存在结构面倾角θ时,应尽量使试件处于下坡受剪状态。

The shear strength parameters of structural plane is one of the important parameters for stability analysis and design of rock mass engineering.Shearing tests were carried out on the weak structural planes of coal rock and sandstone.The least square method,point group center method and reliability analysis method were used to compare and analyze the results.Taking the influence of angleθof structural plane on test results into consideration,modifier formulas of shear strength parameter cohesion c and internal friction angleφ were derived.The results indicated that the least square method was more convenient to determine c andφ when the correlation of the experimental data was relatively good.When the experimental data was highly discrete,the reliability analysis method was more accurate.The values of c andφobtained by the test were lower than the true values due to the angleθof structural plane.The larger the angle,the greater the deviation.When the sample had an angle of structural plane,it should be in a downhill shear condition.