软土地区基坑空间效应和坑底隆起影响分析

发布时间：2018-06-30 04:40

本文选题：软土地区 + 深基坑　；参考：《北京交通大学》2017年硕士论文

【摘要】：随着中国经济的快速发展,城市空间越来越紧张,三维城市空间已经开始成为重要的自然资源。可以说,地下空间的开发利用是二十一世纪城市建设的方向。二十一世纪以来,中国城市地铁建设发展迅速。深基坑工程是一个复杂的跨学科领域,与许多因素相关,是系统工程,虽然国内外专家学者对深基坑工程进行了广泛的深入研究,取得了一些成功的经验,但理论尚不成熟。深基坑事故主要有两个问题:一是深基坑支护系统不稳定;二是深层开挖环境条件,周围既有设施的安全问题,甚至导致严重的工程事故。本文的主要内容如下:(1)总结了基坑工程稳定性及变形的研究现状,介绍了基坑变形规律及支护结构与外围土层的变形关系。(2)介绍了基坑变形的理论分析,并总结了基坑隆起和空间效应的理论知识。(3)通过有限元数值计算研究了长宽比对基坑空间效应的影响,并通过空间效应验算基坑开挖优化方案的可行性;分析了基坑隆起变形产生的原因,并通过数值计算研究基坑隆起的影响因素。(4)通过数值计算模拟苏州太湖新城核心区地下空间工程,计算出数值计算结果,并与现场监测数据进行了分析对比。得出主要结论如下:(1)当基坑长宽比L/B小于2时,按考虑空间效应的方法进行基坑的设计与施工较为经济;而当长宽比L/B大于2时,按二维平面问题进行分析则更为简单、安全。(2)根据太沙基假定,推导了基底隆起影响范围宽度的计算公式,由公式可以看出,基底隆起影响范围宽度的大小主要受到基坑墙体嵌固深度和宽度、土性参数内摩擦角的影响。(3)由数值模拟计算出的变形规律和结果可以用来预测在软土地区的基坑变形。
[Abstract]:With the rapid development of Chinese economy, urban space is becoming more and more tense, 3D urban space has become an important natural resource. It can be said that the development and utilization of underground space is the direction of urban construction in the 21 th century. Since the 21 century, China's urban subway construction has developed rapidly. Deep foundation pit engineering is a complex interdisciplinary field, which is related to many factors and is a system engineering. Although experts and scholars at home and abroad have made extensive and in-depth research on deep foundation pit engineering, some successful experiences have been obtained, but the theory is not yet mature. There are two main problems in deep foundation pit accidents: one is the instability of deep foundation pit support system, the other is the environmental conditions of deep excavation, the safety problems of existing facilities around it, and even serious engineering accidents. The main contents of this paper are as follows: (1) the research status of foundation pit engineering stability and deformation is summarized, and the deformation law of foundation pit and the relationship between supporting structure and surrounding soil layer are introduced. (2) the theoretical analysis of foundation pit deformation is introduced. The theoretical knowledge of uplift and spatial effect of foundation pit is summarized. (3) the influence of aspect ratio on spatial effect of foundation pit is studied by finite element numerical calculation, and the feasibility of optimization scheme of excavation is verified by space effect. The causes of foundation pit uplift deformation are analyzed, and the influencing factors of foundation pit uplift are studied by numerical calculation. (4) the numerical calculation results are obtained by simulating the underground space engineering in the core area of Taihu New City in Suzhou. And compared with the field monitoring data. The main conclusions are as follows: (1) when the aspect ratio of foundation pit L / B is less than 2, it is more economical to design and construct the foundation pit according to the method of considering the spatial effect, but when the ratio of length to width is greater than 2, it is easier to analyze the two-dimensional plane problem. (2) based on the Taishaji assumption, the formula for calculating the width of the influence range of the base uplift is derived. It can be seen from the formula that the width of the influence area of the base uplift is mainly affected by the embedded depth and width of the wall of the foundation pit. (3) the deformation law and results calculated by numerical simulation can be used to predict the deformation of foundation pit in soft soil area.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473

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