软土深基坑变形及环境影响分析方法与控制技术  

Analytical methods and controlling techniques for deformation and environmental influence of deep excavations in soft soils

作　　者：王卫东 WANG Weidong(Arcplus Group PLC,Shanghai 200011,China;Shanghai Engineering Research Center of Safety Control for Facilities Adjacent to Deep Excavations,Shanghai 200011,China)

机构地区：[1]华东建筑集团股份有限公司,上海200011 [2]上海基坑工程环境安全控制工程技术研究中心,上海200011

出　　处：《岩土工程学报》2024年第1期1-25,共25页Chinese Journal of Geotechnical Engineering

基　　金：上海市自然科学基金项目(23ZR1414700);上海市科委重点攻关项目(21DZ1204203,22dz1202901)。

摘　　要：随着基坑规模日益增大以及邻近环境设施愈加复杂,合理评估并控制基坑变形及对周边环境影响成为软土基坑工程面临的重要挑战。基于理论分析与工程应用,对软土深基坑变形与环境影响分析方法及控制技术进行了系统研究。首先,在统筹考虑安全与经济的前提下,提出了软土深基坑环境保护等级和变形控制指标,为基坑周边不同类型环境设施的保护提供了依据。其次,系统建立了便于工程应用的基坑变形影响简化分析方法,并提出了基于土体小应变特性的基坑开挖对环境影响的计算分析方法以及确定全套小应变本构模型参数的实用方法,为复杂环境下深基坑环境影响分析提供了重要手段。同时,针对承压水降水影响难以准确量化评估的难题,提出了根据群井抽水试验反演确定关键水文地质参数并评估深层承压水降水对地层和环境变形影响的计算方法,满足了复杂地层承压水降水影响分析的工程需求。此外,还提出了包括支护结构与主体地下结构相结合、数字化微扰动搅拌桩加固、混凝土支撑主动变形控制、承压水控制超深隔渗帷幕等绿色、低碳、环境低影响的基坑变形控制新技术。成果在全国大量工程中成功应用,促进了软土深基坑工程全过程变形影响精细化分析和系统化控制技术的发展,为大规模地下空间的开发利用提供了技术支撑。It has become a challenge to accurately estimate and reasonably control excavation-induced deformations as well as consequent influences in soft soil areas with the increasing excavation scale and complexity of adjacent facilities.The analytical methods and controlling techniques for the excavation-induced deformations and their subsequent influences have been systematically investigated.The environmental protection grade and deformation controlling standard for the excavations in soft soils are proposed considering synthetically both safety and economy aspects,which provides a basis for protection of different types of facilities close to the excavations.Furthermore,a simplified analysis method is established,helping engineers to get a quick estimation of excavation-induced influences.A sophisticated analytical method considering small strain stiffness of soils is introduced,and a practical method to determine the parameters of small strain constitutive model is proposed,making it possible to evaluate the excavation-induced deformations properly in engineering practices.To tackle the difficulty of quantifying the impact of aquifer pumping,a computational method is proposed to determine the key hydrogeological parameters and to evaluate the pumping-induced deformations based on the field group well pumping tests.Moreover,various green,low-carbon and low-environment-impact controlling techniques are proposed,including preliminary and permanent combination techniques,digital micro-disturbance soil mixing piles,automatically force-compensating concrete struts,ultra-deep soil mixing walls etc.The proposed methods and techniques have been successfully applied in many excavations,promoting further development of fine evaluation methods for the excavation-induced deformations and active protection techniques for complex facilities in urban areas and proactive providing technical support for the development and utilization of underground space.

关 键 词：软土 深基坑 变形控制 环境影响 承压水降水 小应变本构模型 支护结构与主体结构相结合 超深隔水帷幕 

分 类 号：TU470[建筑科学—结构工程]