砂性土基坑变形特征

发布时间：2018-08-01 18:49

【摘要】：改革开放以来,我国经济快速发展,城镇化建设的规模越来越大。滨海城市依靠着其独特的地理优势和舒适的生活环境,使其成为人口集中的首选地区。人口的集中导致城市空间越来越紧缺,充分利用地下空间来完善城市基础设施已成为城市建设中不可缺少的一部分,城市建设过程中相继出现出了大量的复杂深基坑工程。砂性土地基作为滨海城市的工程地质的一个重要特点,是滨海城市基坑工程经常遇到的地质条件。对砂性土地基中基坑变形特征的研究,为滨海城市以后的工程建设具有重要的参考意义。本文紧密结合工程实例,以海口市天利三星级酒店和酒店式公寓及写字楼基坑工程、和信广场基坑工程和美和小区基坑工程为例,在基坑施工过程中对其进行现场监测,总结出砂性土基坑工程变形特征,并对美和小区基坑围护结构进行三维有限元模拟,将模拟结果与监测结果进行对比分析。本文的研究内容以及取得的主要成果如下： (1)本文综述了前人总结的基坑工程变形特点,在砂性土基坑中,基坑开挖引起的变形主要有支护结构发生变形和位移、支护结构后侧的土体发生沉降和位移、基坑底部土体回弹和隆起以及地下水位的变化。 (2)在排桩支护的砂性土基坑中,支护结构顶部水平位移具有跨中大、两边小的特征,竖向位移变化不大,对周边环境主要影响范围在1.5倍基坑深度范围内； (3)在放坡开挖的砂性土基坑中,坡顶各处水平位移变形量比较均匀,竖向位移变化较大,对周边环境主要影响范围在2倍基坑深度范围内。 (4)建立美和小区基坑围护结构的整体三维模型,其模拟的变形特征与实测变形特征相近。
[Abstract]:Since the reform and opening up, China's rapid economic development, the scale of urbanization is becoming larger and larger. The coastal city depends on its unique geographical advantage and comfortable living environment, making it the preferred area of population concentration. The concentration of population leads to more and more shortage of urban space. Making full use of underground space to perfect urban infrastructure has become an indispensable part of urban construction. In the process of urban construction, a large number of complex deep foundation pit projects have emerged one after another. As an important feature of engineering geology in coastal city, sand soil foundation is often encountered in coastal city foundation pit engineering. The study on deformation characteristics of foundation pit in sandy soil foundation is of great significance for future engineering construction in coastal cities. This paper closely combined with engineering examples, taking the excavation engineering of Tianli three-star hotel and hotel-style apartment and office building in Haikou City, Hexin Square Foundation Pit Project and Meihe District Foundation Pit Project as examples, carries on the spot monitoring in the foundation pit construction process. The deformation characteristics of sand soil foundation pit are summarized, and the three-dimensional finite element simulation of the retaining structure of the foundation pit in Meihe district is carried out. The simulation results are compared with the monitoring results. The research contents and main achievements are as follows: (1) this paper summarizes the deformation characteristics of foundation pit engineering summarized by predecessors. In sandy soil foundation pit, the deformation caused by foundation pit excavation mainly includes deformation and displacement of supporting structure. The settlement and displacement of the soil in the back of the supporting structure, the springback and uplift of the soil at the bottom of the foundation pit and the change of the groundwater level. (2) in the sand soil foundation pit supported by piles, the horizontal displacement of the top of the supporting structure is of medium span and large. The vertical displacement has little change on both sides, and the main influence range on the surrounding environment is within 1.5 times of the depth of foundation pit. (3) in the sandy soil foundation pit excavated by slope, the horizontal displacement deformation of the slope top is more uniform. The vertical displacement varies greatly and the main influence range on the surrounding environment is within 2 times of the depth of the foundation pit. (4) the three-dimensional model of the retaining structure of the foundation pit in Meihe district is established, and the deformation characteristics of the simulation are similar to the measured deformation characteristics.
【学位授予单位】：海南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU441;TU433

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