不同加载率作用下的岩石节理本构模型修正

Modification of Constitutive Model of Rock Joints under Different Loading Rates

为了得到更为准确的岩石节理本构模型,在Instron1342伺服控制力学试验机上对岩石节理试样进行了不同加载速率作用下的法向压缩闭合试验,获得不同加载率下节理试样的闭合变形曲线,闭合曲线具有高度的非线性且向上弯曲,曲线斜率随着加载力的增大而增大,最后趋于定值。用五种常用的函数方程对节理闭合变形试验数据进行拟合,得到了拟合效果较好的改进的半对数和改进的指数函数。通过对试验数据的分析,研究了模型参数与加载率之间的关系,从而建立了考虑加载速率效应的节理压缩闭合经验本构模型,并得到试验验证。

In order to obtain a more accurate constitutive model of rock joints,the normal compression closure tests for the specimens of rock joints were carried out at different loading rates on an Instron1342 servo controlled mechanical testing machine. And the closure deformation curves of jointed specimens under different loading rates were obtained. The closure curves are highly nonlinear and bending upward. The slope of the curves increase with the increase of loading force and tend to a constant value at last. The improved semi-logarithm and the improved exponential function with good fitting effect were obtained by fitting the experimental data of joint closure deformation with five functional equations. Through the analysis of the experimental data,the relationship between the model parameters and the loading rate was studied,and the empirical constitutive model of joint compression closure considering the loading rate effect was established and verified by the experiments.