深埋隧道衬砌结构的可靠性方法研究

发布时间：2018-06-28 01:37

本文选题：初期支护 + 可靠度　；参考：《西南石油大学》2014年硕士论文

【摘要】：新奥法是当今隧道建设的主要方法。复合式衬砌则是新奥法施工的精髓部分。故复合式衬砌结构的安全性问题是开展隧道结构安全评价的核心问题。本文基于不确定性因素,为了解决在获取隧道支护结构可靠度过程中的诸多困难,包括各类参数的缺乏,各类因素重要性的差异以及结构安全控制点应力函数的不明确等等,提出了在单因素变化下,对比结构危险点应力状态来确定结构的应力函数,进而求取支护结构可靠度的方法。同时也应用蒙特卡洛法进行了对比分析,做出了有意义的结论。另外一方面,在新奥法施工的地下结构中,现场的监控量测数据是对结构安全状态的重要评价方法。论文应用灰色理论对实际的量测数据进行了理论分析,预测了拱顶下沉位移总量和拱基水平收敛位移总量,并将其与有限元软件计算的结果进行了对比分析,验证了灰色理论的合理性。论文具体的主要研究内容和结论如下： 1、基于实际隧道工程的断面尺寸和支护参数,应用有限元软件建立其理论模型,采用“地层—结构”计算方法,获得了初期支护结构内各节点的应力发展变化情况,即‘结构的轴力从拱顶到边墙逐渐增大达到最大值后,从边墙到隧道断面最低点又逐渐减小。此结果与隧道力学理论相印证,为隧道施工人员提供了对边墙部位进行特殊加固的理论依据。 2、利用灰色理论和回归分析对隧道结构的量测数据进行了分析,发现了在隧道施工过程中,围岩发生最大位移的时间段为开挖后10天以内,为施工设计人员进行支护结构设计提供了理论参考；由灰色理论预测的量测前位移结果可以看出,实际隧道在进行第一次测量前隧道已经进行了较大的沉降,由此提醒施工人员在隧道开挖后需尽快施作支护结构。 3、利用单因素响应面法对衬砌结构的可靠度进行计算,其过程简单实用,包括对随机变量的筛选和剔除都比较方便；对实际工程而言当计算资料比较缺乏时,应用单因素响应面法进行衬砌结构的可靠性分析,能够获得较为满意的计算结果,有效的指导现场人员施工作业。 4、利用蒙特卡洛法对衬砌结构的可靠度进行计算,而且计算结果需要满足一定精度时,相比单因素响应面法而言,蒙特卡洛法的计算量要大得多,而且都是重复性计算；另一方面,从对比500次和1000当计算结果可以看出,随着抽样次数的增加,蒙特卡洛法的精度在不断提高,但总的计算量也在飞速增加,由此决定了蒙特卡洛法只能应用在对计算结果要求比较高,而且具有很强数据处理能力的施工建设中。
[Abstract]:The new Olympic method is the main method of tunnel construction nowadays. Compound lining is the essence of the construction of the New Olympic method. Therefore, the safety of composite lining structure is the core of tunnel structure safety evaluation. Based on the uncertainty factors, in order to solve many difficulties in the process of obtaining the reliability of the tunnel support structure, including the lack of various parameters, the difference of the importance of various factors and the uncertainty of the stress function of the structural safety control points, etc. A method of determining the stress function of the structure by comparing the stress state of the dangerous point of the structure with the change of single factor is put forward, and then the reliability of the supporting structure is obtained. At the same time, the Monte Carlo method is used to make a comparative analysis, and a meaningful conclusion is drawn. On the other hand, the monitoring data is an important method to evaluate the safety of the structure in the underground structure constructed by the New Austrian method. In this paper, the grey theory is applied to the theoretical analysis of the actual measurement data, the total subsidence displacement of the arch roof and the total horizontal convergent displacement of the arch foundation are predicted, and the results are compared with the results of the finite element software. The rationality of grey theory is verified. The main research contents and conclusions are as follows: 1. Based on the cross-section size and support parameters of actual tunnel engineering, the theoretical model is established by using finite element software, and the "stratigraphic structure" calculation method is adopted. The stress evolution of the joints in the initial support structure is obtained, that is, the axial force of the structure increases from the arch to the side wall to the maximum value, and then decreases from the side wall to the lowest point of the tunnel section. This result is confirmed by tunnel mechanics theory and provides theoretical basis for tunnel constructors to carry out special reinforcement of side wall. 2. Using grey theory and regression analysis, the measurement data of tunnel structure are analyzed. It is found that in the course of tunnel construction, the maximum displacement of surrounding rock occurs within 10 days after excavation, which provides a theoretical reference for construction designers to design the supporting structure, which can be seen from the results of pre-survey displacement predicted by grey theory. Before the first survey of the actual tunnel, the tunnel had already undergone a large settlement. Therefore, the constructors are reminded to use the single factor response surface method to calculate the reliability of the lining structure as soon as possible after the tunnel excavation. The process is simple and practical. It is convenient to screen and eliminate random variables, and the reliability of lining structure can be analyzed by single factor response surface method when the calculation data are scarce, and the satisfactory results can be obtained. 4. Monte Carlo method is used to calculate the reliability of lining structure, and when the calculation results need to meet certain precision, compared with single factor response surface method, The Monte Carlo method is much more complicated and repetitive. On the other hand, from the comparison of 1000 times and 500 times, it can be seen that the accuracy of Monte Carlo method increases with the increase of sampling times. However, the total amount of calculation is also increasing rapidly, which determines that Monte Carlo method can only be used in construction with high requirements for calculation results and strong data processing capacity.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U451.4

【参考文献】