深基坑开挖对邻近既有高铁桩基影响研究

发布时间：2018-01-15 01:38

本文关键词：深基坑开挖对邻近既有高铁桩基影响研究　出处：《铁道工程学报》2017年06期 　论文类型：期刊论文

【摘要】：研究目的:大中型城市的市政工程建设高速发展,其中深基坑工程越来越多,由于土地资源稀缺,其不可避免地会近接既有建筑或结构。本文针对深基坑开挖邻近既有高速铁路桥基的少见工况,结合有限元数值模拟进行研究,对基坑围护结构与桩基受深基坑开挖影响的规律进行分析,并结合现场实测数据进行对比验证,以期为今后类似的深基坑近接工程提供参考与指导意义。研究结论:(1)深基坑开挖的卸荷效应使得坑周岩土体平衡状态遭到破坏,进而发生应力重分布;(2)深基坑开挖导致基坑底部隆起,围护结构向坑内发生移动;(3)岩土体应力场改变带来位移场改变,赋存于岩土体中的结构物(如桩基)由于岩土体的运动而发生变形,基本均向坑内移动,桩基上部变形较大,下部变形较小;(4)数值模拟数据与现场实测数据对比基本吻合,基坑开挖完成后产生的变形均处于安全范围,证明了设计的围护与支撑方案对深基坑安全起到有效作用,该支护方案设计以及桩基变形规律研究可应用于今后类似工程中。
[Abstract]:Research objective: the municipal engineering construction of large and medium-sized cities is developing at a high speed, in which more and more deep foundation pit projects, due to the scarcity of land resources. It will inevitably be close to the existing buildings or structures. This paper combined with finite element numerical simulation to study the rare conditions of deep foundation pit excavation adjacent to the existing high-speed railway bridge foundation. The law of foundation pit retaining structure and pile foundation affected by deep foundation pit excavation is analyzed, and the field measured data are compared and verified. The research conclusion is that the unloading effect of deep foundation pit excavation results in the destruction of the equilibrium state of surrounding rock and soil mass, and then the stress redistribution occurs. 2) the excavation of deep foundation pit leads to the uplift of the bottom of the foundation pit and the movement of the enclosure structure to the pit; 3) the change of stress field of rock and soil leads to the change of displacement field, and the structure (such as pile foundation) existing in rock and soil is deformed because of the movement of rock and soil, and all of them move to the pit, and the upper part of pile foundation is deformed greatly. The deformation of the lower part is small; The numerical simulation data are basically consistent with the field measured data, and the deformation caused by the excavation is in a safe range, which proves that the designed envelope and bracing scheme plays an effective role in the safety of deep foundation pit. The design of the support scheme and the study of the deformation law of pile foundation can be applied to similar projects in the future.
【作者单位】：中铁四院集团广州设计院有限公司;
【分类号】：TU753;U213.1
【正文快照】： 研究结论:(1)深基坑开挖的卸荷效应使得坑周岩土体平衡状态遭到破坏,进而发生应力重分布;(2)深基坑开挖导致基坑底部隆起,围护结构向坑内发生移动;(3)岩土体应力场改变带来位移场改变,赋存于岩土体中的结构物(如桩基)由于岩土体的运动而发生变形,基本均向坑内移动,桩基上部变

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