【作者】 徐钦键；

【导师】 李树忱；

【作者基本信息】 山东大学 ， 岩土工程， 2013， 硕士

【摘要】 近些年,随着我国交通结构及基础设施建设的快速发展,公路、铁路及海底隧道的修建越来越多。膨胀性土是影响道路及其它构造物修建的一种特殊性士,但由于膨胀性士质隧道往往跨度大、失稳破坏抢救难度大、维护费用高、社会影响恶劣,在设计、施工中仍存在一定的问题。本文以某膨胀性土质隧道作为工程背景,针对膨胀性土质隧道建设期围岩变形、土体大体积塌方及变形防治等问题,采用了室内试验、数值模拟和工程应用相结合的方法展开了研究工作1、通过对某隧道膨胀性土层的物理力学性质及胀缩特性进行试验研究,揭示了该隧道膨胀性土层的含水率、干密度、结构特征、孔隙比、液塑性指数、抗剪强度、化学成分及膨胀性能等的变化规律,提出了膨胀性能判定的综合办法。2、通过对膨胀性土质隧道建设期出现变形破坏的典型特征、主要类型及危害影响进行总结,为后续膨胀性土质隧道的安全施工提供指导性帮助。3、通过结合隧道洞内变形破坏诱发大体积塌方过程衬砌结构与围岩的变形特征,从支护强度因素及地质因素分析,指出发生变形破坏的产生机理,即：膨胀性土质隧道建设期变形破坏是因边坡滑移而对隧道产生的额外荷载,附加在支护结构上,使得钢拱架屈曲变形。4、在室内试验基础上,开展了膨胀性土质隧道变形演化的模拟试验研究。采用离散元软件UDEC对洞室变形演化过程进行了数值模拟,模拟结果和现场情况基本一致；综合试验现象和模拟分析结果提出了洞室施工的相应建议。5、提出了铁路土质隧道围岩级别划分的亚级细化标准,并根据二次细化结果,判定洞室变形破坏段围岩为Vb偏弱,结合变形破坏特点,给出洞室变形破坏的防止建议：及时封闭地表裂缝；安装临时横、斜支撑,防止隧道坍塌破坏；洞内支护加强；开展地表注浆,加固松散土体。更多还原

【Abstract】 In recent years, with rapid development of China’s transportation structure and infrastructure construction, we have constructed more and more Highway, Railway and Cross-Harbour Tunnels. The expansive soil is a special soil which effects great on roads and other structure constructions. However, due to the large span, difficult rescue, high maintenance costs and bad social impacts, there are still some difficult problems in its design and construction. In this paper, it takes the expansive soil tunnel as the engineering background, focus on the complex problems such as deformations, instabilities and failures, large volume collapse, prevention countermeasures, applies lab tests, numerical simulation and engineering applications to study the deformation failure mode and control measures of the expansive soil tunnels.Firstly, lots of laboratory experiments such as water content, dry density, structural characteristics, void ratio, liquid and plasticity index, shear strength, chemical composition and expansion properties were tested to study the physical, mechanical properties and engineering properties of the expansive soil. The judgment of the expansion capacity was proposed.Secondly, the feature, mode and harm of deformation and mode of the expansive soil tunnel were summarized in order to provide guidance for the subsequent expansion soil tunnel construction. Because of the additional load generated by the sliding slope, which attached to the supporting structure, the steel arch were demaged.Thirdly, due to the deformation and failure process of expansive soil tunnel, supporting strength and geological factors analysis were carried out to pointed out the deformation and failure mechanism of expansive soil tunnel.Fourthly, based on the lab test, the numerical simulation analysis of expansive soil tunnel was carried out. Then the UDEC software was used to simulate the phase. After a comprehensive analysis of the experimental phenomena and numerical simulation results, the construction recommendations are proposed.Finally, the classification of surrounding rock of railway soil tunnels was proposed. Based on the sub-class refinement results, the surrounding rock of deformation and failure was sentenced to less than Vb, which needed to additional supplement support. Considering the feature of the deformation and failure, control measures of expansive soil tunnel was summarized. Closed surface cracks timely; installed the temporary horizontal and inclined support, which were to prevent collapses damaged; carried out surface grouting, which were to reinforcement the earth.更多还原