【作者】 姜彤；

【导师】 马瑾； 许兵；

【作者基本信息】 中国地震局地质研究所 ， 固体地球物理， 2004， 博士

【摘要】 地震荷载作用下边坡的稳定性判定对工程安全具有重要影响，此项研究具有重要意义。本文以节理岩质边坡为对象，借助数值模拟手段、加卸载响应比理论和非线性系统方法，通过对边坡在地震作用下的动力演化过程分析，研究边坡的位移特点，把边坡动力的变形分析与稳定性研究结合起来，回答了边坡在动荷载作用下的稳定性评价问题。 人类对于边坡稳定问题的研究已经进行了100多年，但边坡动力问题是一个涉及多学科交叉的难题，直到目前尚有许多关键问题未能很好解决。本文综述了国内外有关边坡稳定问题的研究现状，总结了当前有关边坡动力稳定问题研究中存在的问题。目前虽有多种方法可用于边坡动力稳定分析，但这些方法各有优缺点，拟静力法能对边坡的稳定性进行粗略评价，不能计算边坡在地震作用下的变形，而Newmark滑块位移法和数值模拟方法仅解决了边坡的变形问题，而不能有效评价边坡的稳定性。如何有效地将边坡的变形分析和动力稳定评价有机结合起来一直是边坡动力稳定研究领域的热点问题。现有相关研究多以均质土坡为研究对象，采用传统的物理、力学方法进行计算，由于各方法理论机制上的差异致使边坡的变形分析和稳定评价之间并无清晰结合点，因此要解决该问题，必须从边坡失稳的演化过程入手，引入新的解决问题的方法、思路和手段。 本文在分析了我国滑坡分布的特点和影响边坡稳定的主要因素之后，探讨了地震力作用下边坡失稳的启程剧动和累计变形效应，并通过有限单元法分析了均质边坡动力响应(位移、速度、加速度)的一般规律。根据边坡在动荷载作用下表现出的非线性特征，受地震预报研究的启发，将加卸载响应比理论(LURR)引入到边坡动力稳定分析研究中，通过对边坡模型的数值计算结果分析，并与尹祥础等人在MTS机上得到的试验结果和数值模拟结果进行对比，从力学和物理学的角度论证了LURR理论应用于边坡动力稳定分析的可行性。 根据加卸载响应比理论的基本原理，选取适用于边坡动力稳定分析的加卸载参数，建立了边坡加卸载响应模型，分别以位移、速度和加速度为响应参数，分析了边坡在地震作用下的加卸载响应特征，并通过输入3种不同频率的地震波，讨论了地震波动频率和位移响应相位差对计算的影响。 为验证本文研究思路的可行性与和合理性，选择研究难度较大的节理岩质边坡作为研究对象，采用离散单元法，分析了节理岩质边坡在地震作用下的变形特征，根据边坡演化过程中所表现出的非线性特征，应用相空间重构理论证明边坡的演化过程是混沌序列，边坡失稳的本质是分岔。通过对边坡输入4组理想正弦波和3组实测地震波论证了边坡系统演化过程中的鞍点是系统的固有属性。提出应用加卸载响应度确定边坡动力稳定性的方法，·从而将边坡的变形分析与稳定性评价有机结合。 最后以马家岩水库右坝肩高边坡为例，应用本文提出的方法进行动力稳定分析，并将计算结果与三维有限元分析的结果进行对比，证明本文提出方法的合理性与正确性。 据以上研究，本文的研究进展可归结为以下3个方面: (l)首次将LURR理论应用于边坡的动力稳定分析研究中，建立了边坡的加卸载响应模型，回答了边坡在动荷载作用下的稳定性评价问题。 (2)按照非线性理论，边坡系统状态的转变可归结为系统向奇异吸引子收缩的过程，鞍点作为奇异吸引子的一种，是边坡从稳定演化至失稳的临界点;通过对边坡输入4组理想正弦波和3组实测地震波论证了边坡系统演化过程中的鞍点是系统的固有属性;边坡动力失稳过程包含2次分岔，并得到了2次分岔存在分离与重合两种类型，以此作为理论基础说明确定边坡演化过程中鞍点的方法。 (3)提出了边坡加卸载响应度的概念，分析了边坡在地震作用下的变形特征以及用加卸载响应度确定边坡动力稳定性的方法，从而将边坡的变形分析与稳定性评价有机结合。 本文的计算尚未考虑孔隙水的作用，对岩土体的动力本构关系亦未进行研究，所得出的结论是否适用于所有边坡有待验证。另外，本文的计算主要针对理想情况进行，对边坡演化过程中出现2次分岔的原因未进行深入探讨，这些都有待于进一步深入研究，拟在今后加强对岩土体本构关系的研究，开展边坡动力响应的模型试验，发展具有实用价值的边坡非线性稳定分析方法。关键词:边坡地震加卸载响应比非线性混沌鞍点变形稳定性更多还原

【Abstract】 The study of slope stability under earthquake load has great implications. This thesis is focused on dynamic analysis of response of jointed rock slope to earthquake by using numerical modeling, the theory of load-unload response ratio and the nonlinear system method. The primary purpose is to solve the problem of combination of deformation analysis and stability evaluation in this research field.More than 100 years have passed since scientists and engineers began to study the stability of slopes. As this is a difficult task involving many disciplines and subjects, many key problems remain unsolved now. In this thesis, a review on the status of slope stability research is firstly presented. Issues are summed up. It found that combination of deformation analysis and stability evaluation for slopes is still the focus in the study field of slopes stability. There are many methods to calculate for deformation or stability, but they can not solve both deformation analysis and stability evaluation, such as pseudo-static method can simply evaluate stability of slopes but can not analyze the deformation of slopes; however Newmark sliding block analysis and numerical methods can calculate the permanent displacements of slopes but can not evaluate stability of slopes. It is mainly because different existed in the basis of theory. So it is difficult to combine deformation analysis with stability evaluation. Only new idea based on the process of slope failure can do that.Focused on issues above, much research works are performed in this thesis. At first, the spatial distribution feature of landslide hazard in china and the primary influencing dynamic stability of slopes are analyzed. The effect of set-out violent slide and progressive failure during earthquakes are presented. Then dynamic responses (displacement, velocity, acceleration) to earthquakes of uniform slopes are calculated by finite element method. Suggested by the study of earthquake prediction, the theory of load-unload response ratio (LURR) is introduced into the analysis of slope dynamic stability. It is verified that the LURR theory is application to this analysis by comparing with the MTS test and numerical calculation results achieved byYinxiangchu.Second, based on the basic theory of LURR, the load-unload response ratio model of slope are established. Take displacement, velocity and acceleration of slopes as response parameters, the load-unload response features of slopes under the affection of earthquake are described. And the affection of frequency of earthquake wave and phasic lag of displacement response are discussed by input three kinds of sine wave.Third, chooses the jointed rock slope as study target. By means of the discrete element method and the load-unload response model, features of deformation are analyzed. Based on their nonlinear characters and the reconstruction theory of phase space, it is proved that the evolution of slope is a chaotic process and the stability failure of slopes is essentially a bifurcation. It is proved that the saddle point is intrinsic attribute of system during its evolution when 4 sets of ideal sine wave and 3 sets of observed seismic wave are input to the slope. A concept of load-unload response degree is suggested. By this concept, the dynamic stability of slopes is determined, and deformation analysis and stability evaluation are well combined.At last, taking the right bank of the Majiayan reservoir as an example, a dynamic analysis is performed using the methods suggested in this thesis. Comparing the calculation results with those of three-dimensional finite element analysis, it is testified that the methods presented in this work are reasonable and correct. The new contributions of this thesis can be summarized as follows:(1) For the first time, this study applies the LURR theory to dynamic stability analysis of slopes, and establishes the load-unload response model of slopes. Answer the stability of slopes under dynamic input.(2) According to the nonlinear theory, the turn of slope system st更多还原