Preface

With the rapid development of urban construction in our country, especially after the 1990s, there has been an increasing number of high-rise and super high-rise building projects. Accompanying this, the excavation area of foundation pits becomes larger and larger, and excavation depth deeper and deeper (some exceeds 30m).
   The foundation pits of high-rise buildings are usually excavated between dense urban building groups. The narrowness of the construction site and the technical difficulties of construction are unprecedented. In addition to ensuring the stability of the foundation pit itself, the excavation of foundation pits must also ensure the safety of adjacent buildings. Therefore, excavating foundation pits in a narrow site will not only bring great difficulties to the design of support, but will also post a great threat to the safe use of adjacent buildings.

   Foundation pit engineering is a highly comprehensive systematic engineering, involving three basic topics of stability, deformation and seepage around soil mechanics. The three, combined together, require comprehensive treatment. It needs not only to study the strength, deformation and stability of soil, but also to study the interaction between soil and structure. At the same time, it is also necessary to study the impact and restriction of construction methods and construction process on rock and soil mass, the control of deformation feedback on structure design, design methods and calculation methods and other important issues. Due to the complexity and uncertainty of foundation pit engineering, information-based construction is very important. Through the real-time detection of construction site, designers can timely modify the deficiencies in the plan based on feedback information, and take active and effective remedial measures. Foundation pit engineering has become a hot issue in the field of geotechnical engineering, while supporting technology a difficult issue.

前 言

随着我国城市建设的快速发展，特别是 20 世纪 90 年代之后，高层和超高层建筑项目日益增多，与之相伴的是基坑开挖面积越来越大、开挖深度越来越深(部分深基坑超过 30m)。
       高层建筑的基坑通常在城市密集的建筑群之间开挖，其场地之狭窄，施工技术难度之大是前所未有的。基坑开挖除要保证基坑自身的稳定外，还必须保证邻近建筑设施的安全，因此在狭窄的场地内开挖基坑不仅会给支护设计带来很大困难。也会对邻近建筑的安全使用造成很大威胁。
       基坑工程一个综合性很强的系统工程，涉及土力学中稳定性、变形及渗流三个基本课题，三者结合在一起，需要综合处理。不但要研究土的强度、变形、稳定性问题，还要研究土与结构的相互作用。与此同时，还需要研究施工方法及施工过程对岩土体的影响和制约，变形反馈对结构设计的控制，设计方法和计算方法等重要问题。由于基坑工程的复杂性和不确定性，信息化施工就显得十分重要，通过对现场的实时检测，设计人员可以根据反馈信息及时修改方案中的不足，采取积极有效的补救措施。基坑工程已成为岩土工程界的热点问题，支护技术则成为难点问题。