骑跨于既有隧道基坑的开挖过程数值模拟  

Numerical simulation of excavation process of foundation pit over existing tunnel

作　　者：汪鹏程[1] 方祥 徐巍 王景 WANG Pengcheng;FANG Xiang;XU Wei;WANG Jing(School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China;Anhui Land Investment Co., Ltd., Hefei 230000, China)

机构地区：[1]合肥工业大学土木与水利工程学院,安徽合肥230009 [2]安徽置地投资有限公司,安徽合肥230000

出　　处：《合肥工业大学学报（自然科学版）》2019年第4期506-511,540,共7页Journal of Hefei University of Technology：Natural Science

基　　金：国家自然科学基金资助项目(51179043)

摘　　要：随着城市轨道交通建设迅猛发展,加上城市土地和空间资源的有限性,使得新建基坑骑跨于既有营运隧道的情形时有发生。文章通过三维有限差分软件FLAC3D建立三维基坑模型,研究基坑在分层分块开挖过程中基坑围护结构、混凝土支撑和抗拔桩的力学特性,分析探讨下卧隧道隆起变形规律。数值模拟结果表明,基坑开挖完成后坑底隆起出现2个峰值,与周边建筑物的影响有关;基坑围护结构弯矩最大出现在基坑的中部,与其水平位移最大值出现的位置相一致;文中实例支撑的轴力以及下卧隧道的隆起均符合控制要求。文中模拟的数值结果以及分析的变化规律可以为今后类似工程提供参考。With the limited land resources and spatial resources and the rapid development of subway tunnels in cities, it becomes common that the new foundation pit crosses over the existing operating tunnel. In this paper, the three-dimensional foundation pit model is established by three-dimensional finite difference software FLAC3D to study the mechanical characteristics of foundation pit retaining structure, concrete support and uplift piles in the process of stratified block excavation. The deformation law of the lower tunnel is also analyzed. The numerical simulation results show that after the excavation of the foundation pit, the two peaks appear on the bottom of the pit, which is related to the influence of the surrounding buildings. The largest bending moment of foundation pit retaining structure occurs in the middle of the foundation pit, which is consistent with the position of the maximum horizontal displacement. The axial force of the inner support and the uplift of the lower tunnel are in accordance with the control requirements. The presented numerical results and variation law can provide a reference for similar projects in the future.

关 键 词：基坑开挖 盾构隧道 变形控制 围护结构 数值模拟 

分 类 号：TU473.2[建筑科学—结构工程]