盾构法隧道施工时高承台被动群桩的土拱效应  

Soil Arching in Passive Pile-Group with Elevated Cap during Shield Driven Tunneling

作　　者：王丽[1] 武钰翔 杨文彬[1] 郑刚[2] 

机构地区：[1]大连交通大学土木与安全工程学院,辽宁大连116028 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300072

出　　处：《大连交通大学学报》2014年第5期51-55,共5页Journal of Dalian Jiaotong University

基　　金：国家自然科学基金资助项目(51208071)

摘　　要：通过建立有限元模型模拟天津市地铁一号线盾构施工,有限元模型得到的土体沉降曲线与现场实测吻合,在此模型基础上进一步研究隧道开挖过程中被动群桩的土拱效应.隧道开挖时,3×3被动群桩中远离隧道的边排桩的桩间土一般形成了"反向土拱";靠近隧道的边排桩的桩间土拱的形式主要取决于同一位置处桩与土体的相对位移.当桩的水平位移小于土体时,桩间土体形成了类似于边坡工程及堆载情况下的土拱;反之,桩间土体形成"反向土拱".桩长增加,当桩、土水平位移接近时桩间土拱效应消失;与地面堆载等典型的被动群桩不同,隧道开挖时当被动群桩的桩间距由4 m减小至2 m时土拱效应消失.The process of shield driven in Tianjin No. 1 subway line project is simulated by finite element meth- od. Results from the finite element model show fine agreement with those acquired in Tianjin No. 1 subway line project. Based on these finite element models, the mechanics of the soil arching is studied in detail. The anti- soil arching always occurs in the rear piles away from the tunnel in the 3 x 3 passive pile-group, while for the front piles near the tunnel, both soil arching and anti-soil arching may occur depending on the displacements of the piles and soils in the same position. Soil arching may not arise as the length of pile enlarges and the lateral displacement at pile top decreases. For the 3 x 3 passive pile-group discussed herein, the soil arching disap- pears when the pile spacing diminishes from 4 m to 2 m ,which is different from the soil arching in the case of surcharge loads.

关 键 词：盾构法 桩-隧道相互作用 被动群桩 土拱效应 反向土拱 

分 类 号：TU473.1[建筑科学—结构工程] U451[建筑科学—土工工程]