边坡安全监测点合理选择有限元计算分析

FEM Analysis of Selection of Reasonable Monitoring Points of Slopes

结合广东乐昌峡水利枢纽工程右岸坝肩边坡,通过有限元强度折减法计算分析,研究如何合理选择边坡位移监测点。首先通过建立有限元计算模型,针对竣工期工况,对边坡进行有限元降强度计算,获得了边坡破坏时的滑动屈服带;然后在边坡表面选择若干点,计算并绘制其位移随边坡降强度折减系数的变化关系。计算结果表明:在滑动区域表面的点,其位移随降强度折减系数不一定是单调变化的,即随着边坡破坏的发展,某些点的位移有可能单调增长,而有些点的位移则出现震荡现象。显然对于位移单调增长的坡面点,有助于通过位移的变化情况判断边坡的稳定性变化情况,可作为观测布置点;而对于位移震荡变化的坡面点,有待进一步研究。滑动体以外的坡面点的位移对折减系数的变化不敏感,对于监控边坡破坏作用不明显。这一研究结果对于边坡位移监测点的选择布置具有理论指导意义。

Based on flood control in Lechang Right Bank Abutment Slope in Guangdong,research is done on how to reasonably choose the displacement monitoring points by the strength reduction finite element calculation.Firstly,a finite element model is established,the slope is calculated by reducing the reduction factor in the condition of the completion of the slope,then the yield area of the sliding slope is obtained.Secondly,some points are selected in the slope surface in the region of sliding,then the change of displacement of the points with the variation of reduction factor is calculated.The results show that the displacement of the points is not necessarily monotonous with the reduction factor,namely,some points may be monotonous increase in the displacement while some points bring forth turbulence with the development of the failure of the slope.Obviously,the monotonic growth points are helpful to the judgment of stability of the slope,so they can be used as observation points while other points should further be studied.The displacement of the points outside the sliding body is not sensitive to the variation of reduction factor,so they have little function for monitoring.The results for the choice of slope displacement monitoring arrangement have important theoretical significance.