重载铁路黄土隧道复合基底沉降控制分析

发布时间：2018-04-30 10:30

本文选题：重载铁路 + 黄土隧道　；参考：《北京交通大学》2017年硕士论文

【摘要】：随着国家西部开发的不断深入以及路网的逐渐完善,重载铁路建设快速进入西北黄土多山地区,为满足行车需要,实现克服高差、缩短里程及优化线性指标的目的,隧道的修建必不可少。目前,国内外对重载铁路的研究主要集中在轨道、路基和桥梁上,关于重载铁路对黄土隧道基底影响的研究较少。我国既有重载铁路隧道的基底设计缺少完善的规范指导,导致在铁路运营期间,部分隧道出现底部开裂破损、翻浆冒泥、下陷等病害,随着轴重增大、运量提高后,这种现象将更加明显,因此对重载铁路黄土隧道复合基底的深入研究具有重要工程意义。本文以大准至朔黄铁路联络线中位于湿陷性黄土区浅埋偏压段的柳条山隧道为工程背景,对灰土挤密桩复合基底沉降控制进行了分析,通过室内试验研究了重塑黄土的工程特性及力学参数,分别采用理论公式和数值模拟计算了复合基底沉降量及变化规律,分析了灰土挤密桩参数设计对复合基底沉降的影响。本文所做的具体工作及主要研究成果如下:1.在搜集和查阅文献资料基础上,总结分析了国内外重载铁路运输发展现状、黄土隧道复合基底加固及灰土挤密桩的应用等方面的研究进展,提出了本文的研究内容及技术路线。2.重塑黄土的室内渗透试验和三轴剪切试验结果表明,重塑黄土的弹性模量与含水率和压实度呈线性关系,黏聚力与含水率和压实度呈指数关系,并为复合基底数值模拟提供了桩间土力学参数。3.建立了重载铁路黄土隧道复合基底沉降计算模型,确定了复合基底荷载条件,通过角点法计算了复合基底附加应力,由分层总和法计算得到了黄土隧道复合基底的沉降量。4.分别建立了隧道基底在不同进深处天然黄土地基和灰土挤密桩复合地基的有限元数值分析模型,分析了地层结构、桩端位置对隧道基底沉降的影响规律,确定了沉降量最大位置在隧道洞口处,并对灰土挤密桩的对隧道基底沉降控制效果进行了研究。5.结合柳条山隧道工程实例,确定了影响复合基底沉降的参数及其合理取值范围,基于正交方法设计试验方案,对各参数进行了显著性检验,得到了桩长变化对基底沉降影响最显著,分析得到了复合基底沉降量与参数的变化呈指数关系,并结合沉降规律对柳条山隧道复合基底的设计提出了优化方案。
[Abstract]:With the development of western China and the gradual improvement of the road network, the construction of heavy-haul railway has rapidly entered the mountainous region of loess in northwest China. In order to meet the requirements of driving, overcome the height difference, shorten mileage and optimize the linear index, the railway construction of heavy haul has entered into the northwest loess mountainous area rapidly. The construction of the tunnel is indispensable. At present, the research on heavy-haul railway is mainly focused on track, roadbed and bridge at home and abroad, but there is little research on the influence of heavy-haul railway on the foundation of loess tunnel. The foundation design of the existing heavy-haul railway tunnel in our country lacks perfect standard guidance, which leads to the cracking and damage at the bottom of some tunnels during the period of railway operation, such as cracking and damage of bottom, mud and mud, subsidence and so on. With the increase of axle load, the volume of transportation increases. This phenomenon will be more obvious, so it is of great engineering significance to study the composite basement of heavy haul railway loess tunnel. Based on the Liutiaoshan Tunnel located in shallow buried partial pressure section of collapsible loess area in the connection line between Dazheng and Shuohuang railway, this paper analyzes the settlement control of composite foundation of lime-soil compaction pile. The engineering characteristics and mechanical parameters of remolded loess were studied through laboratory tests. The settlement and variation law of composite foundation were calculated by theoretical formula and numerical simulation, and the influence of parameters design of lime soil compaction pile on composite foundation settlement was analyzed. The specific work and main research results of this paper are as follows: 1. On the basis of collecting and consulting literature, this paper summarizes and analyzes the development status of heavy-haul railway transportation at home and abroad, the reinforcement of composite foundation of loess tunnel and the application of lime-soil compaction pile, and puts forward the research content and technical route of this paper. The results of laboratory permeability test and triaxial shear test show that the elastic modulus of remolded loess is linearly related to moisture content and compactness, and cohesion is exponentially related to moisture content and compactness. The soil mechanics parameters. 3. 3 are provided for the numerical simulation of composite foundation. The calculation model of composite foundation settlement of heavy duty railway loess tunnel is established, the load condition of composite foundation is determined, the additional stress of composite foundation is calculated by corner point method, and the settlement of composite foundation of loess tunnel is calculated by the method of stratified summation. The finite element numerical analysis models of natural loess foundation and lime-soil compacted pile composite foundation are established in different depths of tunnel foundation, and the influence of stratum structure and pile end position on the settlement of tunnel base is analyzed. The maximum settlement is determined at the entrance of the tunnel, and the control effect of the lime-soil compaction pile on the settlement of the tunnel base is studied. Combined with the example of Liutiaoshan tunnel project, the parameters affecting the settlement of the composite basement and its reasonable value range are determined. Based on the orthogonal design test scheme, the significance of each parameter is tested. The variation of pile length has the most significant influence on the settlement of the foundation, and the exponential relationship between the settlement of the composite foundation and the parameters is obtained, and the optimization scheme for the design of the composite foundation of the Liutiaoshan tunnel is put forward in combination with the settlement law.
【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】：U452.2

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