摘 要
基坑支护工程是一种改善天然土壤以满足设计要求的措施，是在当天然土壤不受剪切强度的影响时。它是综合考虑天然土的土质和建筑物性质的反复分析和计算的过程。
本次设计内容为桃园市地铁车站深基坑支护工程。明挖基坑东西向开挖长度为100 m，南北向宽度为67m，基坑开挖深度为9.5m。所需使用寿命为1年，基坑安全水平为1级。该设计是根据现行国家建设基坑技术规范对施工现场的岩土工程勘测报告和拟建筑物本身的基本情况，来选定本工程的支护方案、降水方案、施工方案，主要目的是掌握基坑支护的设计方法。在考虑支持方案后，桩支撑用于进行详细的设计和计算，包括土压力的计算，桩的设计计算，螺栓的设计计算，基坑的稳定性等，着重于 支撑土的稳定性和外部整体稳定性考虑，多重检查，求出满足支护要求的各个参数，并采用电算软件里正进行验证，得到安全经济的设计参数。降水方案选定为喷射井点，符合土质及土体的渗透性要求，经过分析计算，验证了其可行性，保证了基坑水位符合施工要求及四周边坡的稳定性。施工方案根据现场情况和技术要求全方面考虑，基坑能够顺利的开挖，同时施工现场又有足够的空间，加快了施工的进度，保证周围建筑物和地下设施安全，同时设计方案具有较好的技术经济性。
该设计的主要指导原则是如何保证基坑的安全可靠性，便于施工，达到经济效益。通过本文直观的介绍了基坑支护设计的各种参数。工程技术人员在设计基坑支护时可参考设计方法。
关键词：桩锚支护；施工方案；喷射井点；降水方案
I
Abstract
The foundation pit support project is a measure to improve the natural soil to meet the design requirements, when the natural soil is not affected by the shear strength. It is a comprehensive consideration of the natural soil of the soil and the nature of the building of the repeated analysis and calculation process.
This design content for the Taoyuan City subway station deep foundation pit support project. The excavation length is 100 m, the width of the north and south is 67 m, and the excavation depth is 9.5 m. The required service life of 1 year, the pit safety level is 1 level. The design is based on the current national construction of foundation pit technical specifications of the construction site of the geotechnical engineering survey report and the proposed building itself, the basic situation, to select the project support program, precipitation program, construction program, the main purpose is to master The design method of pit support. After considering the support scheme, the pile support is used for detailed design and calculation, including the calculation of earth pressure, the design calculation of the pile, the design calculation of the bolt, the stability of the foundation pit, etc., focusing on the stability of the supporting soil and the external whole Stability considerations, multiple checks, obtained to meet the requirements of the support of the various parameters, and the use of computer software is being verified, get safe and economic design parameters. The precipitation scheme is selected as the injection well point, which meets the requirement of soil and soil permeability. After analysis and calculation, it verifies its feasibility and ensures that the water level of the foundation pit meets the requirements of construction and the stability of the surrounding slope. Construction plan According to the site conditions and technical requirements in all aspects, the foundation pit can be successfully excavated, while the construction site and there is enough space to speed up the construction of the progress of the surrounding buildings and underground facilities to ensure safety, while the design has a better The technical economy.
The main guiding principle of the design is how to ensure the safety and reliability of the foundation pit, to facilitate the construction, to achieve economic benefits. Through the intuitive description of the foundation pit support design of the various parameters. Engineering and technical personnel in the design of foundation pit support can refer to the design method.
Key words: pile and anchor support; construction scheme; jet well point; precipitation
scheme
II
目录
摘要 ................................................................................................................................................. I Abstract .......................................................................................................................................... II 第1章绪论 .................................................................................................................................... 1 第2章 排桩与锚杆的布置与构造 ......................................................................................... 2 第3章 支护结构上的水平荷载 ............................................................................................. 3
3.1主动土压力计算 ................................................................................................................. 3 3.2被动土压力计算 ................................................................................................................. 7
第4章 排桩与锚杆的设计计算 ........................................................................................... 12
4.1冠梁设计 ........................................................................................................................... 12 4.2排桩设计计算 ................................................................................................................... 12
4.2.1嵌固深度计算 ........................................................................................................ 12 4.2.2桩身弯矩计算 ........................................................................................................ 14 4.2.3截面配筋计算 ........................................................................................................ 16 4.3锚杆设计计算 ................................................................................................................... 18
4.3.1锚杆自由段长度计算 ............................................................................................ 18 4.3.2土锚承载力计算 .................................................................................................... 19 4.4腰梁设计 ........................................................................................................................... 20
第5章 稳定性验算 .................................................................................................................. 21
5.1基坑整体稳定性验算 ....................................................................................................... 21 5.2基坑坑底抗隆起稳定性验算 ........................................................................................... 24
第6章 理正电算 ...................................................................................................................... 26
6.1支护方案 ........................................................................................................................... 26 6.2设计结果 ........................................................................................................................... 30
6.2.1结构计算 ................................................................................................................ 30 6.2.2内力位移包络图 .................................................................................................... 33 6.2.3选筋结果 ................................................................................................................ 35 6.2.4截面计算 ................................................................................................................ 36 6.2.5锚杆计算 ................................................................................................................ 37 6.2.6稳定性验算 ............................................................................................................ 38 6.2.7嵌固深度计算 ........................................................................................................ 41
第7章 基坑降水设计 ............................................................................................................. 43
7.1基坑降水选型 ................................................................................................................... 43 7.2基坑降水计算 ................................................................................................................... 43 7.3材料选择 ........................................................................................................................... 46 7.4施工操作工艺 ................................................................................................................... 47
第8章 支护结构施工组织与工程监测 ............................................................................. 49
8.1支护工程与基坑开挖施工顺序 ....................................................................................... 49 8.2排桩施工 ........................................................................................................................... 49 8.3锚索施工 ........................................................................................................................... 50
III
8.4施工质量组织措施 ........................................................................................................... 51 8.5应急预案 ........................................................................................................................... 54 8.6基坑工程监测 ................................................................................................................... 54
第9章 结论 ............................................................................................................................... 58 参考文献 ...................................................................................................................................... 59 致 谢 ............................................................................................................................................. 60
IV
本科生毕业设计
第1章绪论
1）选题的缘由
基坑工程中的支护与施工对于现代社会城市的基本建设工程至关重要，同时对于基坑工程的研究又是岩土力学学科中比较复杂和困难的问题。其之所以重要，是因为现代社会对于发展高层建筑的追求越来越大，其地下部分起着至关重要的作用，城市的拥挤导致地下交通要更加充分的开发与利用。 2）选题的价值与意义
基坑工程的发展十分迅速，开挖深度由十几米发展到二、三十米。世界许多建筑项目由于深基坑支持错误，造成重大经济损失，甚至造成人员伤亡。在经济方面，对深基坑支护要求是：用最小的投资，尽量最少的外来材料以及最合理的养护力量，在外力的作用下保持其使用质量。在安全方面，通过精细的设计，考虑全面的情况作出最佳的设计方案，保证支护结构可以应对各种突发及潜在的危险。 3）研究思路及预期目标
深基坑支护设计根据设计图纸和使用任务和性质，确定支持方案。在此基础上，结合周边环境和应用的主要技术指标，基坑支护方案设计与比较确定最优支持方案，考虑合理可行的经济性，施工难度，安全稳定性确定最佳支护方案。
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