重力坝坝基面抗滑稳定可靠度分析方法研究

发布时间：2018-05-31 19:01

本文选题：重力坝坝基面 + 抗滑稳定　；参考：《大连理工大学》2014年硕士论文

【摘要】：对于重力坝坝基面抗滑稳定性,早期是使用传统安全系数法来进行安全评价的,但是此方法不能考虑基本参数实际存在的随机性,得到的计算结果不能完全反映客观实际。于是规范进一步规定以可靠度理论为基础的分项系数法来进行重力坝设计,使定值设计转变为非定值设计,以期做到重力坝设计的进一步科学化、合理化。本文基于随机可靠度理论,采用多种可靠度计算方法对重力坝坝基面抗滑稳定性进行了研究,主要内容包括：首先,本文较系统地阐述了几种可靠度计算方法的相关理论。从理论上分析了各种可靠度计算方法的特点和可能存在的不足,以及某些计算方法之间的联系。为应用可靠度分析方法研究重力坝坝基面的抗滑稳定性奠定了理论基础。其次,对传统安全系数法和分项系数法进行了介绍,应用以上两种方法对某水库典型坝段坝基面抗滑稳定性进行了安全评价。但是两种方法得到的结论不一致,传统安全系数法得到的结论是该坝段坝基面不满足抗滑要求,而分项系数法得到的结论是满足抗滑要求。初步分析了造成结论不一致的原因,从而明确本文下一步研究的重要性。最后,结合上述工程实例,采用多种可靠度计算方法对坝基面的抗滑稳定性进行了详细研究。通过对各随机变量进行敏感性分析,得出抗剪断摩擦系数、黏聚力和上游水位是三个主要敏感因子。抗剪断摩擦系数和黏聚力的概率分布类型的改变对三个主要敏感因子的敏感系数影响比较大。不考虑抗剪断摩擦系数和黏聚力之间的负相关性得到的重力坝坝基面抗滑稳定性可靠指标偏小,计算结果偏于安全。抗剪断摩擦系数和黏聚力均服从正态分布时,计算得到的可靠指标偏小,抗剪断摩擦系数和黏聚力概率分布类型的改变对可靠指标有较大的影响。不考虑抗剪断摩擦系数、黏聚力和上游水位变量截尾分布时,计算得到的可靠指标偏小,其中考虑上游水位截尾分布对可靠指标的影响最大。通过对各可靠度计算方法在本文工程实例中的对比研究,得出广义JC法和广义映射变换法的实用性最强。综合各种方法的安全评价结论,本文认为工程实例中的重力坝坝基面满足抗滑要求。
[Abstract]:The traditional safety factor method is used to evaluate the anti-slide stability of gravity dam foundation surface in the early stage, but this method can not consider the randomness of the actual existence of the basic parameters, and the calculated results can not reflect the objective reality completely. So the code further stipulates that the method of partial coefficient based on reliability theory is used to design gravity dam, so that the design of fixed value can be changed into non-fixed value design, in order to make the design of gravity dam more scientific and reasonable. Based on the theory of random reliability, this paper studies the stability of gravity dam foundation surface against sliding by using various reliability calculation methods. The main contents are as follows: First of all, this paper systematically describes several reliability calculation methods related to the theory. In this paper, the characteristics of various reliability calculation methods and their possible shortcomings are analyzed theoretically, as well as the relations between some calculation methods. It lays a theoretical foundation for the application of reliability analysis method to study the stability of gravity dam foundation surface. Secondly, the traditional safety factor method and the sub-factor method are introduced, and the safety evaluation of the anti-slide stability of the dam foundation surface of a typical dam section of a reservoir is carried out by using the above two methods. However, the conclusions obtained by the two methods are inconsistent. The traditional safety factor method has come to the conclusion that the dam foundation surface of the dam section does not meet the requirements of anti-slide, while the conclusion obtained by the sub-factor method is that the anti-slide requirement is satisfied. The reason of the inconsistency is analyzed, and the importance of the next research in this paper is clarified. Finally, the anti-slide stability of the dam foundation surface is studied in detail by using various reliability calculation methods combined with the above engineering examples. Through the sensitivity analysis of each random variable, it is concluded that the friction coefficient of shear resistance, cohesion force and upstream water level are three main sensitive factors. The change of the probability distribution type of shear friction coefficient and cohesion force has a great influence on the sensitivity coefficient of the three main sensitive factors. Without considering the negative correlation between shear friction coefficient and cohesive force, the reliability index of anti-slide stability of gravity dam foundation surface is small, and the calculation result is safety. When the shear friction coefficient and the cohesion force are obtained from the normal distribution, the calculated reliability index is small, and the change of the shear friction coefficient and the probability distribution type of the cohesion force has a great influence on the reliability index. When the shear friction coefficient is not considered, the reliability index is small when the cohesion force and the tail distribution of the upstream water level variables are considered, and the influence of the upstream water level truncation distribution on the reliability index is the greatest. By comparing and studying the reliability calculation methods in this paper, it is concluded that the generalized JC method and the generalized mapping transformation method are the most practical. Synthesizing the safety evaluation conclusions of various methods, this paper thinks that the dam foundation surface of gravity dam in engineering example can meet the requirement of anti-slide.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV223

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