【作者】 项永杰；

【导师】 刘新荣；

【作者基本信息】 重庆大学 ， 土木工程， 2011， 硕士

【摘要】 随着我国西部大开发战略的深入实施及高速公路交通事业的迅猛发展,山岭公路隧道的建设呈现出精彩纷呈的局面。隧道建设的数量和类型日益增多,遇到了越来越多的技术难题。本文以山西省忻保高速公路钻钱门隧道为工程背景,通过理论分析、现场实测、数值模拟相结合的方法,研究和探讨浅埋偏压隧道的施工力学效应,并对该类型隧道施工风险进行评估。主要研究工作如下:①通过对钻钱门隧道典型浅埋偏压断面的监控量测成果分析,指出或是由于地形偏压使得偏压断面左右拱腰的钢拱架产生受力不均的现象。②借助有限元分析软件ANSYS建立不同最小覆盖层厚度、不同地表坡度、不同围岩地质条件下的18种浅埋偏压隧道计算模型,研究了各工况的隧道围岩位移场、应力场、初期支护应力、二次衬砌应力的变化规律。③在分析主应力空间中未屈服面与屈服面应力点的相互关系的基础上,提出了隧道围岩承载效应系数的概念,并推导了基于Drucker-Prager准则的隧道围岩自承效应系数公式,得出了可利用围岩承载效应系数来定量判断隧道围岩承载效应的发挥程度,并依据不同部位围岩承载效应系数的不同来判断围岩的破坏顺序。④对18个浅埋偏压隧道开挖算例进行分析,提出以隧道偏压效应程度和隧道围岩的承载效应发挥程度来综合判断隧道的稳定性。将算例结果作为贝叶斯网络参数学习的案例,利用专业贝叶斯软件Netica建立浅埋偏压隧道施工风险分析模型,并对设计案例进行了概率推理计算、最大可能解释计算和敏感性分析。结果表明,所建模型的风险分析结果比较符合实际。更多还原

【Abstract】 With the implementation of the western development strategy, and the rapid development in highway transportation, the construction of mountain road tunnel in the western is presenting a brilliant situation.The quantities of tunnel increase fast,and encountered more and more technical problems.This paper combines Zuan Qianmen tunnel in Shanxi Province, and takes it as the project background. Through the theoretical analysis,field measurement and finite element numerical simulation method, the paper studies and explores the construction mechanics of shallow buried bias tunnel and its risk assessment of excavation. The research of this paper is as follows:①According to analyse the results of monitoring measurement, indicated maybe the phenomenon of steel arch’s unevenly stressing is the results of terrain bias.②Build 18 numerical models in conditions of different minimum safe thichness of over burden, different land slope, different geological conditions by means of finite element analysis software ANSYS. Analyze and summary the stress of tunnel,first timbering,second timbering,and the displacement condition.③This paper analyzes the relationship between stress points on yield surface and not, then puts forward the concept of load effect coefficient (LEC),at last derives the function of LEC based on Drucker-Prager criterion.Load effect can be quantitative described by LEC,and tunnel can be determined the sequence of stress damage by the value of the different regions’LEC.④The result of 18 examples suggests the stability of tunnel can be measured by the effect of asymmetrically loaded and the load effect of surrounding rock. In this thesis,BBN is applied in risk analysis model for shallow buried bias tunnel using BBN software Netica. In order to get cases for parameter in BBN(Bayesian Belief Network),18 FE examples are calculated. This risk analysis model is also applied to some interesting fields,such as probability inference,most probable explanation and sensitivity analysis.Calculated results indicate this model is fit for real project.更多还原