岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
3期
759-764
,共6页
孙树林%王天宇%刘小芳%余文平%夏银枫
孫樹林%王天宇%劉小芳%餘文平%夏銀楓
손수림%왕천우%류소방%여문평%하은풍
边坡稳定性%非圆弧临界滑动面%单变量方法%最速梯度法%交替变量局部梯度法
邊坡穩定性%非圓弧臨界滑動麵%單變量方法%最速梯度法%交替變量跼部梯度法
변파은정성%비원호림계활동면%단변량방법%최속제도법%교체변량국부제도법
slope stability%non-spherical critical slip surface%univariate method%steepest descent method%alternating variable local gradient method
临界滑动面的获得是土质边坡稳定性分析中一个必要的过程,然而现有分析方法难以保证该临界滑面的准确性,而且部分分析方法在计算过程中会陷入局部最小值陷阱。基于单变量方法和最速梯度法,提出了交替变量局部梯度法,该方法能够突破最优化方法应用在边坡稳定性分析上的瓶颈。首先,通过斯宾塞极限平衡方法和网格搜索法(或者其他确定临界滑面的方法),获得边坡初始椭球状临界滑面;其次,在该滑面上布置若干节点作为变量,目标函数为安全系数Fs关于空间节点坐标Zi的方程,为了使目标函数快速降低,沿负梯度方向循环优化每个节点,当满足一定精度要求时,即可获得三维土质边坡非圆弧状临界滑动面;最后,通过算例证明该方法可行,计算结果可靠。
臨界滑動麵的穫得是土質邊坡穩定性分析中一箇必要的過程,然而現有分析方法難以保證該臨界滑麵的準確性,而且部分分析方法在計算過程中會陷入跼部最小值陷阱。基于單變量方法和最速梯度法,提齣瞭交替變量跼部梯度法,該方法能夠突破最優化方法應用在邊坡穩定性分析上的瓶頸。首先,通過斯賓塞極限平衡方法和網格搜索法(或者其他確定臨界滑麵的方法),穫得邊坡初始橢毬狀臨界滑麵;其次,在該滑麵上佈置若榦節點作為變量,目標函數為安全繫數Fs關于空間節點坐標Zi的方程,為瞭使目標函數快速降低,沿負梯度方嚮循環優化每箇節點,噹滿足一定精度要求時,即可穫得三維土質邊坡非圓弧狀臨界滑動麵;最後,通過算例證明該方法可行,計算結果可靠。
림계활동면적획득시토질변파은정성분석중일개필요적과정,연이현유분석방법난이보증해림계활면적준학성,이차부분분석방법재계산과정중회함입국부최소치함정。기우단변량방법화최속제도법,제출료교체변량국부제도법,해방법능구돌파최우화방법응용재변파은정성분석상적병경。수선,통과사빈새겁한평형방법화망격수색법(혹자기타학정림계활면적방법),획득변파초시타구상림계활면;기차,재해활면상포치약간절점작위변량,목표함수위안전계수Fs관우공간절점좌표Zi적방정,위료사목표함수쾌속강저,연부제도방향순배우화매개절점,당만족일정정도요구시,즉가획득삼유토질변파비원호상림계활동면;최후,통과산예증명해방법가행,계산결과가고。
It is necessary to obtain the critical slip surface in soil slope stability analysis. However, the existing analysis methods can not ensure the accuracy;and some analysis methods may fall into local minimum trap in the process of calculation. In order to obtain a non-spherical critical slip surface that is most similar with the actual slip surface, an alternating variable local gradient method is proposed based on univariate method and steepest descent method. This method can break through the bottleneck of optimization method applied to slope stability analysis. At first, the initial critical ellipsoidal slip surface of slope can be determined by Spencer limit equilibrium method and the grid search method (or any other method to determine the critical slip surface). Then, several nodes are arranged on the slip surface as variables;the objective function is an equation of safety factor Fs versus space node coordinates Zi;to make the value of objective function decrease fast, each node is optimized according to the negative gradient direction in every cycle. When the result meets the accuracy requirements, the non-spherical critical slip surface of the three-dimensional soil slope is obtained. Finally, this method is proved to be feasible and accurate by two examples.