深埋硐室围岩压力上限解与结构体系可靠度

发布时间：2018-11-08 07:24

【摘要】：摘要：地下工程作为岩土工程的一个重要研究方向,在交通、矿山、国防等工程领域发挥着重要作用。而深埋硐室稳定性问题又是地下工程研究的焦点。如何对深埋硐室进行准确的安全评价是岩土工程师们一直关注的热点。如何准确获得深埋硐室的围岩压力是岩土工程界的难点。极限分析理论基础严谨,分析过程简单,在计算过程中不需要对弹塑性变形的全过程进行分析,而直接关注于岩土的极限破坏状态,通过构建机动容许的速度场以及静力容许的应力场,根据虚功率原理来求解深埋硐室围岩压力的上、下限解,是解决深埋硐室围岩压力的有效途径之一。而关于深埋硐室安全性的评估,与安全系数相比较,可靠度作为评价安全性的指标更为科学。因此,本文将极限分析方法与可靠性理论相结合,对深埋硐室的围岩压力和稳定性问题进行研究,为今后深埋硐室的支护设计和稳定性评估提供理论依据。论文主要创新性成果如下： 1、构建了深埋硐室平动与转动相结合的破坏机制,即由“楔形塌落体+转动圆弧体+n个平动三角形体”构成,并且得到了深埋硐室围岩压力的最优解。通过对比分析,当三角形块体数n变大时,围岩支护反力的上限值趋于稳定,计算精度也变高；而当n=3时则可满足围岩压力的精度要求。此外,基于构建的深埋硐室的破坏机制(三角形块体数n=3),将本文极限分析方法计算所得的围岩压力与普氏理论以及数值模拟方法的计算结果进行了对比,最大差值小于30%,则验证了本文深埋硐室破坏机制的合理性。 2、基于深埋硐室的破坏机制,利用极限分析上限定理分别得到了线性与非线性Mohr-Coulomb破坏准则下围岩压力的解析解,并且分析了非线性系数以及岩土各参数对围岩压力的影响。 3、基于深埋硐室的破坏机制,利用极限分析上限定理得到了Hoek-Brown破坏准则下围岩压力的解析解,并且分析了Hoek-Brown破坏准则中各参数以及岩土各参数对围岩压力的影响。 4、分别建立了含单一和含多个功能函数的多失效模式相关下结构体系可靠度的一般模型,提出了利用Monte Carlo模拟法直接进行编程计算可靠度的方法,给出了具体的计算步骤和流程图,并且基于不同模型分别得到了结构体系可靠度的相对精确值。 5、基于Mohr-Coulomb破坏准则和Hoek-Brown破坏准则分别建立了多失效模式相关下深埋硐室结构体系可靠性模型。采用MonteCarlo模拟法计算了模型的可靠度,通过参数敏感性分析得到了影响深埋硐室结构体系可靠度的主要因素。 6、以通平高速公路的姜源岭隧道以及山脚树煤矿21128采区运输平巷为例,采用极限分析上限法计算了深埋硐室围岩压力的大小,并且与数值模拟和现场实测的结果进行了对比,其一致性验证了本文方法的正确性。图99幅,表61个,参考文献204篇。
[Abstract]:Abstract: as an important research direction of geotechnical engineering, underground engineering plays an important role in traffic, mining, national defense and other engineering fields. The stability of deep-buried chamber is the focus of underground engineering research. How to accurately evaluate the safety of deep-buried chambers is a hot spot that geotechnical engineers have been paying close attention to. How to accurately obtain the surrounding rock pressure of deep-buried chamber is a difficult point in geotechnical engineering. The theoretical basis of limit analysis is rigorous and the analysis process is simple. In the course of calculation, it is not necessary to analyze the whole process of elastic-plastic deformation, but to pay close attention to the limit failure state of rock and soil. According to the principle of virtual power, the upper and lower limit solutions of surrounding rock pressure of deep buried chamber are obtained by constructing the allowable velocity field of maneuver and the stress field of static tolerance. It is one of the effective ways to solve the surrounding rock pressure of deep buried chamber. Compared with the safety factor, the reliability is more scientific in evaluating the safety of the deep-buried chamber. Therefore, this paper combines the limit analysis method with the reliability theory to study the surrounding rock pressure and stability of the deep buried chamber, which provides the theoretical basis for the support design and stability evaluation of the deep buried chamber in the future. The main innovative achievements of this paper are as follows: 1. The failure mechanism of the combination of translational and rotational motion of deep chamber is constructed, which is composed of "n translational triangles of wedge collapse body rotating circular arc body". The optimum solution of surrounding rock pressure of deep chamber is obtained. Through comparison and analysis, when the number of triangular blocks n increases, the upper limit value of surrounding rock support reaction force tends to be stable, and the calculation accuracy becomes higher, while when n = 3, it can meet the precision requirement of surrounding rock pressure. In addition, based on the failure mechanism of the deep buried chamber (triangle block number nm3), the surrounding rock pressure calculated by the limit analysis method in this paper is compared with the calculation results of Pushmann theory and numerical simulation method. The maximum difference is less than 30, which verifies the rationality of the failure mechanism of the deep chamber in this paper. 2. Based on the failure mechanism of deep buried chamber, the analytical solutions of surrounding rock pressure under linear and nonlinear Mohr-Coulomb failure criteria are obtained by using the upper limit theorem of limit analysis, respectively. The influence of nonlinear coefficient and geotechnical parameters on surrounding rock pressure is analyzed. 3. Based on the failure mechanism of deep buried chamber, the analytical solution of surrounding rock pressure under Hoek-Brown failure criterion is obtained by using the upper limit theorem of limit analysis, and the influence of various parameters of Hoek-Brown failure criterion and geotechnical parameters on surrounding rock pressure is analyzed. 4. The general model of reliability of structure system with multiple failure mode correlation is established, and the method of programming reliability is put forward by using Monte Carlo simulation method. The detailed calculation steps and flow charts are given, and the relative accurate values of the reliability of the structure system are obtained based on different models. 5. Based on the Mohr-Coulomb failure criterion and the Hoek-Brown failure criterion, the reliability models of deep chamber structures with multiple failure modes are established. The reliability of the model was calculated by MonteCarlo simulation method, and the main factors affecting the reliability of deep chamber structure were obtained by parameter sensitivity analysis. 6. Taking Jiangyuanling Tunnel of Tongping Expressway and 21128 Mining area of Shanjiaoshu Coal Mine as examples, the pressure of surrounding rock of deep buried chamber is calculated by the upper limit method of limit analysis, and compared with numerical simulation and field measurement. Its consistency verifies the correctness of this method. There are 99 pictures, 61 tables and 204 references.
【学位授予单位】：中南大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU45

【参考文献】