盾构井围护结构变形监测与数值模拟

摘要：以广州市轨道交通十三号线一期工程夏园站～南岗站区间设置的盾构井兼轨排井深基坑为研究对象，制定了深基坑围护结构变形监测方案，并且分析不同工况下围护结构水平位移随地连墙埋深变化规律。采用有限差分软件FLAC3D对基坑开挖过程进行数值模拟，对比分析监测数据和围护结构计算结果，同时对围护结构进行优化分析。分析结果表明：地连墙加支撑和环框梁组成的围护体系，能很好限制围护结构变形，实际监测数据证明了数值模拟及参数选取的合理性。支撑位置的变化对围护结构变形控制起重要作用，增大地连墙埋深可以减小围护结构水平位移。

Abstract： Taking the deep foundation pit of shield well and track panel well in the section between Xiayuan Station and Nangang Station of Guangzhou Rail Transit Line 13 Phase I project as the research object， the deformation monitoring scheme of supporting structure of deep foundation pit was formulated， and the variation law of horizontal displacement of supporting structure with the buried depth of diaphragm wall under different working conditions was analyzed. The finite difference software FLAC3D was used to simulate the excavation process of the foundation pit. The monitoring data and the calculation results of the retaining structure were compared and analyzed. At the same time， the optimization analysis of the retaining structure was carried out. The analysis results show that： the supporting frame and the ring frame beam are very good to limit the deformation of the supporting structure. The rationality of numerical simulation and parameter selection is proved by the actual monitoring data. The change of supporting position plays an important role in the deformation control of supporting structure and increasing the buried depth of ground connection can reduce the horizontal displacement of supporting structure.

关键词：深基坑;围护结构;监测;数值模拟

Key words： deep excavation;supporting structure;monitor;numerical simulation

中图分类号：TV551.4                                    文献标识码：A                                  文章編号：1006-4311（2020）22-0104-04

0  引言

随着地铁的大规模建设，深基坑工程不断出现，基坑的稳定性便成为基坑工程主要考虑问题。深基坑围护结构变形是导致基坑事故的重要原因，国内外学者对深基坑施工过程变形规律进行了大量研究[1-3]。但由于基坑工程地质条件的复杂性，以及基坑计算方法和参数选取没有统一规定，基坑围护结构稳定性已成为设计和施工主要关注问题。基坑施工过程现场监测和数值模拟是研究基坑围护结构变形规律的主要方法[4-6]，本文以盾构井深基坑为背景，制定监测布置方案，并采用数值模拟方法计算，将监测数据和计算结果对比分析，分析深基坑施工过程中围护结构变形规律，并且对围护结构进行优化分析，为类似深基坑工程提供参考借鉴。……