比较两种折减法在岩质边坡稳定性分析中的差异

摘要

In order to analyze the influence of calculation results obtained through different reduction methods on the sta-bility of rock slopes ,the finite element software Plaxis was adopted to compare the differences of overall strength reduction method and partial strength reduction method in analyzing the stability of the rock slope of Dongfeng Reservoir from the aspect of stability coefficient ,displacement and plastic failure of the slope .The analysis showed that the safety coefficient was respectively 1 .474 and 1 .476 with the overall and partial strength reduction methods when the slope was in its natu-ral state ,moreover the coefficients were basically the same with the two methods after the slope was reinforced .The change of the slope displacement was close to that of the reduction coefficient according to these two methods ,whereas when the reduction coefficients were the same with these two methods ,the horizontal and vertical displacement were larger with the overall strength reduction method ,with an approximate margin value of 5mm of the horizontal displacement and 11mm of the vertical displacement .The critical slip surfaces determined by the two methods were the same ,however the plasticity points and failure points were more and distributed more widely with the overall method .%为分析不同强度折减法计算结果对岩质边坡稳定性影响，采用有限元软件 Plaxis ，以东风水库岩质边坡为例，从边坡安全系数、位移及塑性破坏区三方面比较了整体强度折减法与改进的局部强度折减法在分析边坡稳定性过程中的差异。分析表明，边坡天然状态下，采用整体折减法和局部折减法得到的安全系数分别为1．474和1．476，而对边坡进行加固处理后，两种方法得到的安全系数几乎一致，且支护效果明显；两种方法反映出的边坡整体位移随折减系数变化趋势较为接近，而折减系数相同时，采用整体折减法得到的水平和竖直位移均较大，且边坡发生破坏时，水平位移值比局部折减法大5 mm 左右，竖直位移比局部折减法大11 mm 左右；两种折减法确定的危险滑裂面相同，但整体折减法下的塑性点和拉断点明显较局部折减法中的分布更多，范围更广。