龙洞堡机场车站隧道基底深厚软弱地层处理技术研究

发布时间：2018-05-04 20:16

本文选题：软弱地层 + 群桩效应　；参考：《西南交通大学》2016年硕士论文

【摘要】：目前,随着城市经济建设的迅猛发展,高速客专也随之进入飞速发展阶段,其中包含较高比例的隧道,由于高速列车的通过性要求高,当隧道处于软弱地层中时,其基底处理面临巨大挑战。本文依托于龙洞堡国际机场下穿高速铁路工程,对隧道基底深厚软弱地层处理技术进行研究,获得以下主要研究成果：(1)阐述了软弱地层隧道的基本力学特征,研究对比了各种软弱地层隧道施工方法及基地加固方式,选用了群桩与衬砌支护联合承载体系改良地基,并阐述了群桩力学效应及承载性能。(2)通过建立三维有无地基改良模型,研究对比地基改良前后不同开挖步隧道结构的沉降、应力情况,得到了开挖过程中隧道洞室力学行为的变化情况,揭示了地基群桩改良对控制隧道沉降及保证列车运行安全的有效性。(3)通过建立三维数值模型,研究群桩与衬砌联合承载体系中群桩在不同桩长、桩径、横向间距、纵向间距下衬砌、围岩的受力及变形分布情况,并在此基础上对隧道群桩-衬砌联合承载体系进行优化设计,揭示了在不同群桩设计参数下对隧道结构的影响规律。(4)基于群桩与衬砌联合承载体系优化设计模型,拟合出不同桩基设计参数(桩长、桩径、桩基横距、桩基纵距)下群桩的受力模型计算公式,可极大简化隧底群桩的工程设计。(5)通过在轮轴对上施加振动力时程曲线,并对列车施加列车前进方向的行驶速度场,可以模拟振动荷载的大小和位置变化,从而可以较为精确地模拟隧道结构动力响应随列车行驶速度和位置的发展变化,揭示出群桩基底对控制列车振动效应有显著作用。
[Abstract]:At present, with the rapid development of urban economic construction, high-speed passenger specialized has also entered the rapid development stage, including a higher proportion of tunnels, because of the high speed train passing requirements, when the tunnel is in the weak stratum, Its base treatment faces great challenges. In this paper, based on the high-speed railway project under Longdongbao International Airport, the deep soft stratum treatment technology of the tunnel basement is studied, and the following main research results are obtained: 1) the basic mechanical characteristics of the soft stratum tunnel are expounded. This paper studies and compares various construction methods and base reinforcement methods of tunnels in soft strata, selects the combined bearing system of pile group and lining support to improve the foundation, and expounds the mechanical effect and bearing capacity of pile groups. By studying and comparing the settlement and stress of tunnel structures with different excavation steps before and after foundation improvement, the variation of mechanical behavior of tunnel caverns during excavation is obtained. This paper reveals the effectiveness of foundation pile group improvement in controlling tunnel settlement and ensuring the safety of train operation. Through the establishment of three-dimensional numerical model, the paper studies the pile group in different pile length, pile diameter and transverse spacing in the combined bearing system of pile group and lining. On the basis of the stress and deformation distribution of the lining and surrounding rock under the longitudinal spacing, the optimum design of the combined bearing system of the tunnel pile group and lining is carried out. The influence of different pile group design parameters on tunnel structure is revealed. Based on the optimal design model of combined bearing system of pile group and lining, different design parameters of pile foundation (pile length, pile diameter, transverse distance of pile foundation) are fitted. The calculation formula of the force model of pile group under the longitudinal distance of pile foundation can greatly simplify the engineering design of pile group at the bottom of the tunnel by applying the vibration force time history curve on the wheel shaft pair and applying the speed field of the train forward direction to the train. The variation of vibration load and position can be simulated, and the dynamic response of tunnel structure can be accurately simulated with the development of train speed and position. It is revealed that pile group foundation plays a significant role in the control of train vibration effect.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U455.49

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