【作者】 胡志军；

【导师】 任建喜； 宣振军；

【作者基本信息】 西安科技大学 ， 建筑与土木工程， 2007， 硕士

【摘要】 本文以北京地铁奥运支线森林公园车站南坑为工程背景,给出了地铁基坑维护设计方案和施工方法,采用现场监测、有限元法模拟和理论分析等方法研究了影响地铁深基坑稳定的主要因素,得到了地铁车站深基坑的变形规律,完成了基坑稳定性评价。研究结果表明:森林公园车站南坑基坑维护方案设计对是合理的;采用分层分小块的基坑土方开挖法是减小时空效应的有效施工方法;桩顶水平位移反映支护结构的顶部变形情况,能直接反映支护结构变形特性,是支护结构安全状况的重要指标,过大的桩顶位移往往是支护结构破坏的前兆。钢支撑的位置及安装时机对基坑稳定性影响很大,设置钢支撑对减小支护结构变形和弯矩十分有利,钢支撑的温度应力作用明显,现场监测结果表明设计的预应力施加值偏大,造成一定的浪费。地铁车站深基坑工程是一个复杂的系统工程,影响其稳定性的因素很多,维护设计方案、施工方法和地质条件是影响深基坑变形的主要因素;因素之间的相互作用大,在开挖过程中,基坑及其支护结构的应力、变形随着时间、空间的变化不断变化,监控量测反馈的信息化施工方法对基坑工程稳定非常重要。更多还原

【Abstract】 Based on the South Pit of Senlin Park Station of Beijing Olympic Subway branch, the maintenance plan and construction method are given. The main factors affecting the stability of deep subway excavation are studied with the in-situ monitoring, FEM simulation and theory analysis. The deformation laws of the deep excavation of subway station are obtained, and the stability assessment of the excavation is accomplished.The studying results are as follows. The maintenance plan of South Pit of Senlin Park Station is reasonable. The excavation method of separated layer and little portion excavation is effective to reduce space-time effect during the construction process. The horizontal displacement value of pile top is an important index to the safety condition of the maintenance structure, and reflects the deformation characteristics of the maintenance structure, especially the pile top. Excessive horizontal displacement value of pile top is always the precursor of the destroy of maintenance structure. The place and time setting steel pile brace influence the excavation stability obviously, and is useful to reduce the deformation and moment of maintenance structure. Otherwise the thermal stress influences the steel pile brace. The in-situ monitoring result shows that the pretension force is a little large, which causes some waste. Deep excavation of subway station is a complex system project. There are many factors affecting its stability. The influence factors affect each other. During the excavation process, the stress and deformation of the excavation and maintenance structure change with time and space. Monitoring information is very important to the foundation pit stability.更多还原