兰州某深基坑在降水下支护结构性能分析

ANALYSIS OF SUPPORTING STRUCTURE PERFORMANCE OF A DEEP FOUNDATION PIT IN LANZHOU UNDER PRECIPITATION

为探讨兰州地区土钉加桩锚组合式支护结构在降水作用的结构性能.文中以兰州某深基坑工程为研究背景,采用PLAXIS 2D对基坑工程进行了考虑降水和未考虑降水两种工况的数值分析.结果表明上部土钉墙、下部桩锚支护结构体系在开挖支护过程中,两种不同的支护体系中土钉墙部位整体位移较大,桩锚支护部位整体位移较小;在未考虑降水作用下桩身嵌固段弯矩比考虑降水作用下的大,开挖深度范围内桩身最大弯矩数值小于考虑降水作用下桩身弯矩数值;基坑地表竖向沉降影响范围约为1.5倍基坑深度的范围内;滑动面绕过排桩桩底形成了贯通的滑动区.

Taking a deep foundation pit project in Lanzhou as the case,the numerical analysis of the foundation pit project with and without precipitation is carried out by PLAXIS 2D to investigate the structural performance of soil nails and pile anchor combined support structure under precipitation in Lanzhou areas.In the support of the upper soil-nailed wall and the lower pile-anchor support structure system,the results show that the overall displacement of the soil-nailed wall part in the two different support systems is larger,and the overall displacement of the pile-an-chor support part is smaller.The bending moment of the embedded section of the pile body without considering the action of precipitation is larger than that under the action of considering the precipitation,and the maximum bending moment of the pile body within the excavation depth range is smaller than that of the pile body under the action of precipitation;the vertical settlement of the foundation pit surface is about 1.5 times the depth of the foundation pit;the sliding surface bypasses the pile bottom to form a through sliding area.