软硬交替地层超深竖井受力特性及合理分层开挖厚度探讨  

Discussion on mechanical characteristics of ultra-deep shaftsin boulders and reasonable layered excavation thickness

作　　者：王旭 任荣 周王鹏 陈保国[2] WANG Xu;REN Rong;ZHOU Wangpeng;CHEN Baoguo(Sinohydro Bureau 7 Co.,Ltd.,Chengdu 610081,Sichuan,China;Engineering Faculty,China University of Geosciences,Wuhan 430074,Hubei,China)

机构地区：[1]中国水利水电第七工程局有限公司,四川成都610081 [2]中国地质大学(武汉)工程学院,湖北武汉430074

出　　处：《工程建设》2024年第5期11-15,共5页Engineering Construction

基　　金：中国水利水电第七工程局有限公司科技攻关项目(LT-02-ZY-2022-[科研]-01)。

摘　　要：某检修排水井尺寸规模大,开挖深度深,所处地层条件复杂,具软硬交替特征。为确保竖井深基坑开挖稳定性,提高施工效率,利用三维数值模拟软件FLAC3D对该超深竖井基坑开挖施工全过程进行仿真模拟,分析5种不同分层开挖厚度情况下超深竖井结构受力和变形特性。研究表明:1)地连墙的最大环向应力和最大水平位移均随分层开挖厚度的增加而增加,在软岩地层范围内出现应力和变形突增,在硬岩地层范围内出现应力和变形骤减;2)以无内衬开挖下地连墙最大环向应力和最大水平位移为参考标准,单层开挖厚度范围为3~4 m对地连墙位移具有很好的约束效果,建议实际工程中土层开挖及软岩开挖时采用3 m分层厚度,硬岩部分地层开挖时采用4 m分层厚度。A maintenance drainage well has a large scale,deep excavation depth,complex formation conditions and boulders.In order to ensure the stability of the excavation of the deep foundation pit and improve the construction efficiency,the whole process of the excavation of the ultra-deep shaft foundation pit is simulated by using the three-dimensional numerical simulation software FLAC 3D,and the stress and deformation characteristics of the ultra-deep shaft structure under five different layered excavation thicknesses are analyzed.The results show that:1)The maximum hoop stress and maximum horizontal displacement of the diaphragm wall increase with the increase of layered excavation thickness,and the stress and deformation spurt occur within the soft rock strata,and the stress and abrupt deformation deceleration occur within the hard rock stratum;2)Taking the maximum hoop stress and maximum horizontal displacement of the diaphragm wall under unlined excavation as the reference standard,the thickness range of single-layer excavation is 3~4 m,which has a good restraining effect on the displacement of the diaphragm wall,and it is recommended that the layered thickness of 3 m should be used for soil excavation and soft rock excavation in actual engineering,and the layered thickness of 4 m should be used for the excavation of hard rock part of the formation.The results can provide guidance for on-site shaft construction and provide reference for ultra-deep shaft excavation under similar background.

关 键 词：超深竖井 地连墙 软硬交替地层 分层开挖 水平位移 

分 类 号：TU473.2[建筑科学—结构工程]