软土地区超深基坑引发邻近既有车站变形的主动控制方案研究

Study on active control scheme of settlement of adjacent important buildings caused by super deep excavation in soft soil area

摘要

为了解决深大基坑开挖引发邻近既有车站产生过大变形的问题，利用有限元软件在深大基坑与既有车站之间的地层中进行注浆，改变基坑周围的土体位置，推动地铁车站结构向基坑外侧产生变形，从而将车站水平位移控制在较小的目标值以内。研究了不同的注浆位置，提出了三种注浆方式，分别是通长注浆、分段注浆和多点注浆，通长注浆指整个注浆范围内单位长度注浆量自上而下保持相同；分段注浆指将注浆范围分为若干段等长的注浆体，每一段注浆体的单位长度注浆量根据注浆体所在位置的地层位移确定；多点注浆指若干段独立注浆体的长度很小，只在车站楼板深度位置进行集中注浆，每一段注浆体的注浆量根据所在地层位移确定。通过比较达到相同的车站变形控制目标时，不同注浆条件下的车站结构受力情况，选择出最佳的注浆方案。

Abstract

In order to solve the deep foundation excavation causes nearby existing station produces large deformation problems, using finite element software, grouting is carried out in the stratum between the deep foundation excavation and the existing station, push the subway station structure to the inside of the foundation excavation, thus the horizontal displacement of the station is controlled within a smaller target value. Different grouting positions are studied and three grouting method are proposed, which are through-length grouting, segmenting grouting and multi-point grouting. Through-length grouting means that the grouting amount per unit length remains the same from top to bottom in the whole grouting range.Segmenting grouting refers to dividing the range of grouting into several sections of equal length grouting body, and the grouting amount per unit length of each section is determined according to the stratum displacement of the position of the grouting body. Multi-point grouting refers to the fact that the length of several independent grouting bodies is very small, and only concentrated grouting is carried out at the depth of the station floor. The amount of grouting of each grouting body is determined according to the displacement of the stratum. By comparing the stress of station structure under different grouting conditions when the same station deformation control target is achieved, the best grouting scheme is selected.

关键词

有限元模拟 / 超深基坑 / 邻近车站 / 注浆

Key words

finite element simulation / ultra-deep foundation excavation / adjacent station / grouting

Author summay

张 贺(1984—), 男, 高级工程师, 硕士, 主要从事地下工程研究。E-mail: [e-mail]