位移突变判据中监测点的位置和位移方式分析

Analysis of locations and displacement modes of monitoring points in displacement mutation criteria

选择边坡内某些监测点的位移突变特征作为强度折减法的材料破坏判据。为分析监测点的位置和位移方式选取的合理性,分别对均质土坡和节理岩质边坡建立数值模型。在坡体内布置若干点,记录这些点在3种位移方式下位移和折减系数的关系。根据关系曲线的特征,建立双曲线拟合方程,结果表明:①相关系数接近1,拟合效果较好;②临界滑移线内及滑移线上各点均可作为突变判据的监测点;由于坡顶位置较容易确定,且必位于滑移线内,建议在一般边坡中选取坡顶作为监测点;③3种位移均可作为监测的位移方式。

The displacement mutation characteristics of monitoring points were chosen as the failure criteria of materials in the shear strength reduction method. In order to analyze the rationality of the chosen locations and the displacement modes of monitoring points, numerical models were founded for isotropic soil slope and joint rock slope, respectively. Some monitoring points were located in a slope. The relationships between the displacement and the reduction factor were analyzed. According to the displacement mutation characteristics of displacement-reduction factor curves, hyperbolic fitting equations were founded. It was shown that firstly, the correlation coefficients of the fitting results were close to 1, indicating that the fitting data were in good correlation with the monitoring data; secondly, the points on and below the critical slip line could be chosen as the monitoring points of displacement mutation criteria; the top of slope was recommended to be chosen as the monitoring point in the universal slope with the consideration that the top of the slope was sure to be below the critical slip line and its location was easy to be obtained; thirdly, all the three displacement modes could be chosen for monitoring.