支挡式软土深开挖影响区既有桩基础建筑灾变机理研究

With the accelerating urbanization process and the mass population gathering towards big cities, underground space development becomes an effective way to solve the problems of urban disease. Damage of building with pile foundation induced by deep excavation occur frequently in the dense regions of the city. Study on the failure mechanism of adjacent building with pile foundation has important practical significance. A series of research methods such as, theoretical calculation, numerical simulation,indoor model tests, field tests, are adopted to study the failure mechanism of adjacent piled buildings. The research focus on the interaction mechanisms among retaining wall, soil, serving pile and the bearing performance of changes of the serving pile during the process of excavation. The main purpose of the research is to establish building deformation forecast methods based on the supporting structure parameters and adjacent building parameters. Evaluation system on the piled buildings cataclysm will be established through the research. Meanwhile, the optimized excavation supporting design scheme and building protective measures will be proposed.

随着我国城市化进程的加速以及人口向中大城市的聚集，地下空间开发在解决“城市病”方面变得尤其重要。城市密集区域深开挖工程引起的邻近既有桩基础建筑破坏现象不断增多，对深开挖引起的桩基础建筑破坏机理方面进行研究具有重要的现实意义。项目采用理论建模、数值模拟、室内模型试验和现场试验等研究方法，对深开挖引起的邻近既有桩基础建筑破坏机理进行研究，重点研究支护结构-土体-在役桩基的相互作用以及深开挖施工条件下主动区既有受荷基桩承载性能和附加变形演化规律，建立以支护体系参数及周围建筑设施参数为指引的建筑变形预测方法。通过该项目的研究，形成深开挖诱发邻近桩基础建筑物灾变的评价体系，进而优化深开挖围护设计方案以及邻近建筑保护措施。

软黏土地基基坑深开挖工程引起的邻近既有建（构）筑物变形甚至破坏现象不断增多，造成了严重的经济社会问题。课题采用模型试验、数学建模、三维数值分析以及工程实测等方法对软黏土地基深基坑工程引起的邻近建筑变形进行研究，提出了软黏土地区不同类型内支撑围护结构（灌注桩、SMW工法桩、地下连续墙）的变形特性以及邻近土体变形规律，建立了基坑开挖引起的邻近浅基础建筑变形计算模型，给出了基于空间效应的深基坑邻近浅基础建筑三维病害计算模型；根据围护结构邻近土体位移规律，研究了围护结构-软黏土-在役桩基的相互作用机理及影响因素，建立在役桩基附加侧阻及附加端阻的在土体位移场作用下的数学计算模型及并给出了模型参数取值方法，分别给出了基坑开挖引起的邻近桩基础建筑附加内力及变形计算模型。通过对围护结构变形引起邻近设施变形计算模型的建立，能够预测拟建深基坑工程可能引起的邻近建（构）筑物设施病害，建立基于邻近建（构）筑物保护的施工及监测预警机制，课题的研究成果具有重要的社会及经济效益。