局部锚固失效下桩锚支护体系深基坑力学响应分析

摘要 以某砂土层桩锚支护结构深基坑为工程背景，基于有限元程序Plaxis建立数值计算模型，对单排锚索失效、双排锚索失效两种局部锚固失效工况分别进行模拟，研究了预应力锚固失效引起的支护结构力学响应规律，揭示了锚固失效后的锚索荷载传递规律.研究表明:相对于单排锚索失效情况，双排锚索失效对基坑支护结构变形及内力的影响较大;在群锚失效最不利工况下，桩体最大弯矩和位移分别为正常工况时的1.66倍和1.74倍;桩体弯矩增大倍数是决定桩体是否发生破坏的重要指标.
Abstract：Under the engineering background of anchored pile supporting excavation in sand layers， numerical models were established using the FEM program Plaxis to simulate excavations under two local anchor failure conditions of one-row and two-row anchor cable failures. The effect of prestressed anchor failures on mechanical response of retaining structures was studied. Besides， the load transfer response to the anchor failures was revealed. The results obtained from the numerical simulations show that the influence of two-row anchor cable failure on deformation and internal force of retaining structure was larger than that of one-row anchor cable failure. Under the most unfavorable condition of group anchor failures， the bending moments and displacements of retaining piles were 1.66 and 1.74 times of those under the normal construction condition， respectively， and the increase ratio of the bending moment of the retaining piles was the crucial determining factor of the piles failure.