摘 要

近年来随着经济的发展，社会的进步，城市化进程的加快，高层建筑和市政工程大量涌现。高层建筑的建造、大型市政设施的施工及大量地下空间的开发，必然会有大量的深基坑工程产生。建筑物高度越高，其埋置深度也越深，相应的对基坑工程的要求也就越高。深基坑支护结构的设计、施工、监测等是近年来经常遇到的技术难题。深基坑支护不仅要求确保边坡的稳定，而且要满足变形控制要求，保证基坑内正常作业安全，而且要防止基坑及坑外土体移动，保证基坑附近建筑物、道路、管线的正常运行。为了满足如今建筑物的支护，基坑工程也在朝更大、更深的要求迈进。正是由于基坑工程具有很强的区域性和个性，因此根据不同的区域和个性特征,研究相应的基坑稳定性、支护结构的内力及变形以及周围地层的位移对周围建筑物和地下管线等的影响及保护的计算分析，以便采取经济、实用的基坑支护方案，就具有重要的理论意义和实际效益。本工程为广东省佛山市二号线1期工程第9座车站石梁站的主体基坑的围护结构的设计。首先根据规划要求与当地实际情况，确定围护方案为钻孔灌注桩，并用3道内支撑，外围使用止水帷幕。同时根据长度选取3个不同的计算截面，1-1，2-2，3-3截面。计算过程主要使用水土合算及朗肯土压力理论计算出土压力，再用分层开挖支撑不变法计算各支撑的力与弯矩，并计算出最大弯矩。再根据混凝土与钢结构理论进行桩体与支撑的配筋计算。在基坑稳定验算时，使用plaxis2D软件电算验证稳定性，设计是否合理。最后是附属结构（围檩，冠梁，腰梁）的设计，以及施工组织与监测设计。

关键词：深基坑；钻孔灌注桩；内支撑；设计

Design of Supporting Structure for Deep Foundation Pit of Shiliang Subway Station

Abstract

In recent years, with the development of economy, the progress of society and the acceleration of urbanization, a large number of high-rise buildings and municipal projects have emerged. The construction of high-rise buildings, the construction of large-scale municipal facilities and the development of a large number of underground space will inevitably produce a large number of deep foundation pit projects. The higher the height of the building, the deeper the depth of its embedment, and the higher the requirements for the foundation pit engineering. In recent years, the design, construction and monitoring of deep foundation pit support structure are often encountered technical problems. Deep foundation pit support not only requires to ensure the stability of slope, but also to meet the requirements of deformation control, to ensure the safety of normal operation in the foundation pit, but also to prevent the movement of foundation pit and soil outside the pit, to ensure the normal operation of buildings, roads and pipelines near the foundation pit. In order to meet the support of today's buildings, the foundation pit engineering is also moving towards greater and deeper requirements. It is precisely because of the strong regionality and individuality of the foundation pit project, it is of great theoretical significance to study the influence of the stability of the foundation pit, the internal force and deformation of the supporting structure and the displacement of the surrounding stratum on the surrounding buildings and underground pipelines, and to calculate and analyze the protection, so as to adopt an economical and practical foundation pit supporting scheme, according to the characteristics of different regions and individualities. Practical benefits. This project is the design of retaining structure of the main foundation pit of Shiliang Station, No. 9 Station, Phase 1 Project of Foshan No. 2 Line, Guangdong Province. Firstly, according to the planning requirements and the local actual situation, it is determined that the enclosure scheme is bored cast-in-place piles, which are supported by three internal supports and waterproof curtain is used in the periphery. At the same time, three different cross sections, 1-1, 2-2, 3-3, are selected according to the length. In the calculation process, the soil pressure is calculated by using the theory of soil and water balance and Rankine earth pressure, and then the force and moment of each support are calculated by using the method of invariant support of layered excavation, and the maximum bending moment is calculated. Then the reinforcement calculation of pile body and support is carried out according to the theory of concrete and steel structure. When checking the stability of foundation pit, the PLAXIS 2D software is used to verify the stability and rationality of the design. Finally, the design of accessory structure (purlin, crown beam, waist beam) and construction organizationand monitoring design.

Keywords：Deep foundation pit;Bored cast-in-place pile;Internal support;Desigin

目录

1 工程概况 1

1.1 车站概况 1

1.3 工程地质及水文地质条件 1

1.3.1 地形地貌 1

1.3.2 岩土分层及其特性 2

1.3.3 水文概况 2

1.4 基坑施工 3

1.4.1 基坑支护结构 3

1.4.2 基坑降排水 4

1.4.3 对既有建（构）的监测保护 4

1.4.4 管线保护 4

1.5 本章小结 5

2 基坑支护结构设计计算书 6

2.1 设计计算 6

2.1.1 地质计算参数 6

2.1.2 计算方法 7

2.2 1-1截面支护结构设计计算 7

2.2.1 土压力计算 8

2.2.2 支撑轴力及桩身长度计算 11

2.2.3 桩体配筋计算 16

2.2.4 支撑参数的确定 17

2.2.5 基坑稳定性验算 19

2.3 本章小结 23

3 2-2截面支护结构设计 25

3.1 土压力计算 26

3.2 支撑轴力及桩身长度计算 28

3.3 桩体配筋计算 33

3.4 支撑参数的确定 34

3.5 基坑稳定性验算 38

3.6 本章小结 40

4 3-3截面支护结构设计计算 42

4.1 土压力计算 43