【作者】 张宇川；

【导师】 谭忠盛；

【作者基本信息】 北京交通大学 ， 岩土工程， 2007， 硕士

【摘要】 近十几年来,特长公路隧道顺应社会需要,迅猛发展起来。由于隧道长度增加,地质条件愈发复杂,我们需要借助信息化施工,科学化施工,通过新的科技手段进行量测和及时的数据处理来进行有效的反馈,改进施工方法,在保证安全和质量的前提下提高施工速度。本文以雪峰山特长公路隧道为依托,充分利用理论分析,数值模拟和现场试验多种手段,进行了隧道施工围岩收敛快速量测方法研究、初始地应力场及围岩参数的反分析、结构稳定性评价、软弱围岩条件超前支护加固措施研究、复合式衬砌中二次衬砌合理施作时机、隧道不同围岩支护参数优化分析研究,主要研究成果如下:(1)选择不同类别围岩地段典型断面的隧道变形量测资料进行反分析,得到隧道的初始地应力场及围岩的力学参数。(2)采用三维有限元程序对施工过程力学效应进行计算分析,围岩力学参数及初始地应力场可采用反分析得到的结果,并与地质调查资料相结合,评价隧道施工过程的稳定性。选择典型断面,根据围岩压力的实测值以及初支与二衬之间的接触压力,采用荷载结构模型和结构分析软件分析初支结构的稳定性和二衬结构的稳定性。(3)雪峰山隧道软弱围岩地段的超前支护类型进行研究,主要从理论研究上超前支护加固机理、采用数值方法模拟超前支护加固的力学效应、结合实际工程研究超前支护的施工工艺。(4)以隧道周边变形值为控制依据,采用特征曲线法来确定二衬的施作时机,首先对不同围岩类别选择典型断面分析围岩及初期支护的特征曲线,再由二次衬砌的结构特征分析支护曲线,根据这两条曲线、变形值以及工程类比就可以分析确定二衬施作的合适时机。(5)根据已有的施工监测断面,选择两个有代表性的断面,长期量测初衬及二衬之间的接触压力,监测时间在稳定以后一段时间,由此确定作用在二衬上的荷载特征,在此基础上,进一步计算分析二次衬砌的结构内力,评价二衬长期荷载作用下的可靠度。(6)不同围岩支护参数优化,优化范围:衬砌形状的局部优化、初衬及二衬厚度的优化、锚杆的长度及布置优化、钢格栅的形式及间距优化等。更多还原

【Abstract】 In recent ten years, to satisfy the necessity of society, the extra long highway tunnel was developing rapidly. Because the tunnel length was increasing and the geological conditions became more and more complicated, we have to use information construction and science construction, and need effective feedback from measurement with new science and technology. In order to improve the construction method and enhance the construction speed in term of safety and quality, we used the Xuefengshan tunnel as background, made full use of theoretical analysis, numerical simulation and experimentations, etc. We researched the method of measuring the convergence of surrounding rock quickly, the back analysis of the initial ground stress field and the parameter of surrounding rock, the estimate of the structure stability, the pre-support in the weak surrounding rock condition, the optimum time to construct the secondary lining in composite linings, and the optimum analysis of the support parameter of different surrounding rock. The main results are as follows:(1) We back analyzed the deformation data of typical cross-section of different surrounding rock, and gained the initial ground stress field and the mechanics parameter of surrounding rock.(2) We adopted the three dimension finite element program to calculate and analyze the mechanics effect in the construction progress. The surrounding rock’s mechanics parameter and initial ground stress field can be used together with the result of the back analysis and the geological survey data, to evaluate the stability of the tunnel in construction. We chose the typical cross-section, on basis of the measure data of the surrounding rock’s stress and the contact pressure between the initial lining and the secondary lining, adopted load structure model and structure-analysis software to analyze the stability of early support and the secondary lining.(3) The research of the pre-support style of the weak surrounding rock in Xuefengshan tunnel was mainly carried out in form of studying the principle of the pre-support in theory, adopting numerical method to simulate the mechanics effect of the pre-support, studying the pre-support construction technology combining with the practice of the construction.(4) Taking the tunnel’s surrounding deformation as the control criterion, we determined the construction time of the secondary lining through the characteristic curve method. Firstly, we chose representative section to analyze the characteristic curve of surrounding rock and primary support according to different surrounding rocks, then we took advantage of the secondary lining structure characteristic to analyze supporting curve. With the two curves, the deformation data and project analogy, we could determine the optimum time of the secondary lining construction..(5) Based on the gotten construct monitoring section, we chose two representative sections to measure the contact pressure between primary support and secondary lining. If it kept stability for a long time, we could know the characteristics of the secondary lining, so we could get the inner force by calculation and analysis and evaluate the secondary lining’s reliability under long term load application.(6) The optimization of different surrounding rock parameters and the range of optimization: the local optimization of lining form, the thickness optimization of primary support and secondary lining, the optimization of anchor’s length and distribution, the optimization of steel grid’s form and interval, and so on.更多还原