基于城市复杂环境的深厚淤泥质土层深基坑开挖与变形控制综合研究

Comprehensive Study on Deep Excavation and Deformation Control of Thick Soft Clay Layers in Urban Complex Environments

随着城市化进程的推进和城市环境的复杂化,深基坑工程在利用城市地下空间方面变得越发重要。深厚淤泥质土层因其低承载力、高压缩性和低渗透性特点,为基坑开挖施工带来了显著挑战,尤其在建筑密集、地下设施密集和水文地质条件复杂的区域,这些因素对基坑土体变形控制提出了更高的要求。本研究以城市复杂环境为背景,系统地探讨了深厚淤泥质土层基坑开挖中的变形控制策略及关键技术。首先,通过对淤泥质地层的工程特性研究,分析了城市深厚淤泥质土层的特殊地质条件及其对基坑开挖的影响。接着,结合实际工程案例,研究了在软土地区复杂环境下实施的不同支护变形控制措施。研究了某软土地区地铁车站深基坑工程和某隧道明挖段深基坑工程中的不同支护变形控制措施,并评估了这些措施在实施过程中的效果。研究发现:1) 在支撑结构下方有效实施适当加固可以较好控制基坑变形;2) 提高出土效率对减少淤泥质软土基坑的变形至关重要;3) 在深厚淤泥质土层进行深基坑工程时,采用的地连墙支护和混凝土支撑显示出优良的稳定性。当坑底位于淤泥质土层时,在支撑底部进行裙边加固能显著提升变形控制效率。最后,通过两个工程案例的实际效果验证了所提出技术方案的可行性和有效性,为类似工程提供了宝贵的参考与指导。

As urbanization progresses and urban environments become more complex, deep excavation engineering is becoming increasingly important for the utilization of underground urban spaces. Thick layers of soft, silty clay present significant challenges for excavation due to their low bearing capacity, high compressibility, and low permeability characteristics. These challenges are particularly pronounced in areas with dense buildings, numerous underground facilities, and complex hydrogeological conditions, all of which place higher demands on soil deformation control. This study, set against the backdrop of a complex urban environment, systematically explores deformation control strategies and key technologies for deep excavations in thick, silty clay layers. Firstly, by investigating the engineering characteristics of silty clay layers, we analyzed the special geological conditions of deep urban silty clay layers and their impact on excavation. Then, combining actual engineering cases, we explored different support deformation control measures implemented in the complex environments of soft soil regions. We studied various support deformation control measures in a deep excavation project for a subway station in a soft soil area and in a cut-and-cover tunnel section, and assessed the effectiveness of these measures during implementation. The study found that: 1) Effectively implementing appropriate reinforcement below the supporting structure can better control excavation deformation;2) Enhancing excavation efficiency is crucial for reducing deformation in silty clay deep excavations;3) In deep excavation projects within thick silty clay layers, the diaphragm wall support and concrete bracing demonstrate excellent stability. When the excavation bottom is located within silty clay layers, edge reinforcement at the base of the bracing can significantly enhance deformation control efficiency. Finally, the practical results from the two engineering cases validated the feasibility and effectiveness of the proposed technical solutions, providing valuable references and guidance for similar projects.