The FEM Analysis Of The Earth-slope Stability Problem

Recently,with the rapid development of economy,many area of our country builda lot of fundamental facilities,such as freeways,railways,airports,seawalls,rail roadembankments,earth dams and SO on．In these engineering projects,earth slopes havebeen widely used and inevitably exist the stability problem．The analysis of slopestability has a great impact on economy and safety．Lots of loss arises from thelandslide annually．As a yardstick of slope stability,safety factor is influenced by manyfactors during the course of calculation．The safety factor rightly selected,which slopestability requires,has a great importance to the reasonable j udge of slope stability．Atpresent,in some slope stability calculation,although safety factors are greater than 1．0.the landslide still OCCur,while some embankment are stable,but their safety factorscalculated are less than 1．0．These indicate the terrible complexity of influence of safetyfactor calculated． Among the nonlinear analysis approaches,load-control method and displacemenf-control are the main tools of primitive parametric contr01．But the formeris appropriate to track pathway only before its flexure and the latter Can be used to tracethe whole process．But when the freedom is multiple,the displacement of control point,whose displacement must increase,is difficult to select．So the displacement control method is not appropriate to multiple freedom structure．In addition,when structure deformation j umps back,displacement—control method isn't fit for it．In a word,the method of load increment control curbs,52．while displacement control method bridles,su,and the arc-length method simultaneously controls both△λand Au to keep the interior product of displacement vectors constant．One of the important originalities in this dissertation is to introduce arc—length method to the Finite Element Method(FEM)program,made use of arC—length method to track the whole process of structure deformation until to its failure,automatically hunt for and precisely define the critical state Of structure failure． This dissertation expounds in detail the present theories and approaches of analysis of the slope stability at home and abroad,comparing their discrepancy and th．eir virtues and defects,formulizing the principle,steps and processes of FEM program,elaborating arc-length method and the derivation of how to realize the processes andsteps of arc—length,and then arc-length method is used to the FEM theory,compiled theanalysis program of slope stability(APSS)．Finally,four engineering cases arecalculated through APSS program to prove the reliability,stability and good astringencyof arc-length method,and display its superiority and advance during the．course of hunting for extreme value．...