地震作用下岩质边坡稳定性及风险分析研究
发布时间：2018-10-19 16:15
【摘要】：地震作用下,岩质边坡失稳和破坏产生的后果往往很严重,给人民和国家的财产安全造成重大损失。尤其是汶川地震之后,地震引起的滑坡失稳越来越受到人们的重视。三峡大坝蓄水时发生许多微小地震,这些地震对库区边坡的长期稳定性到底有多大影响,也是人们十分关注的问题。本文结合国家自然科学基金项目(41372356),采用理论分析和数值模拟等方法,对地震作用下岩质边坡稳定性及风险进行了较为系统深入的研究,主要研究工作和成果有:①以均质岩质边坡和含软弱夹层岩质边坡算例为基础,充分讨论强度折减法的失稳判据条件。对比几种典型的失稳判据得到不同边坡稳定性安全系数后,确定采用关键点位移\速度时程曲线收敛的失稳判定标准,并以此标准结合动力强度折减法求得相应算例边坡的动力安全系数。②讨论了岩质边坡强度参数、坡高、坡度、地震波振幅和频率及软弱结构面参数对岩质边坡稳定性的影响规律。结果表明:提高边坡强度参数有利于提高边坡稳定性,内摩擦角比粘聚力对边坡稳定性影响更大;稳定性安全系数随着坡高和坡度的增大而降低;安全系数随地震波振幅及频率的增大而减小以及软弱结构面对边坡稳定性影响较大。③对三峡库区某大型含软弱结构面边坡进行FLAC 3D数值模拟,分别研究其在静力下的稳定性及地震作用下的动态响应过程和失稳机理。分析岩质边坡在地震作用下的破坏过程,得到软弱结构面对边坡动力特性影响较大的结论。并采用强度折减法求该边坡在静力和地震作用两种工况下的稳定性安全系数。④根据边坡稳定性影响因素,结合三峡库区某大型含软弱结构面边坡的工程地质条件特点,对该边坡进行风险因子的识别,确定影响边坡稳定性的指标主要包括地质(地质构造和岩土体质量)、边坡结构面、边坡结构、地震、水文(降雨和地下水)条件和人类活动。由风险因子评估表对边坡进行风险分析。将风险分析结果与FLAC 3D模拟结果进行对比,证明边坡的安全系数在地震作用下已经超过安全范围。
[Abstract]:Under the action of earthquake, the consequences of rock slope instability and destruction are often very serious, which results in great loss to the property safety of people and countries. Especially after Wenchuan earthquake, people pay more and more attention to landslide instability caused by earthquake. Many small earthquakes occurred when the three Gorges Dam was storing water. How much influence these earthquakes have on the long-term stability of the slope in the reservoir area is also a problem that people pay close attention to. Based on the project of National Natural Science Foundation (41372356), this paper makes a systematic and in-depth study on the stability and risk of rock slope under earthquake by using the methods of theoretical analysis and numerical simulation. The main research work and results are as follows: 1 based on the examples of homogeneous rock slope and soft intercalated rock slope, the instability criterion conditions of strength reduction method are fully discussed. By comparing several typical instability criteria to obtain the safety factors of different slope stability, the criteria for the convergence of displacement / velocity time-history curves at key points are determined. The dynamic safety factor of the slope is obtained by combining the criterion with the dynamic strength reduction method. 2 the strength parameters, slope height and slope degree of the rock slope are discussed. The influence of amplitude and frequency of seismic wave and parameters of weak structural plane on the stability of rock slope. The results show that increasing the strength parameters of the slope is beneficial to the stability of the slope, the angle of internal friction has more influence on the stability of the slope than the cohesive force, and the coefficient of stability safety decreases with the increase of the slope height and gradient. The safety factor decreases with the increase of the amplitude and frequency of the seismic wave, and the stability of the slope is greatly affected by the weak structure. 3 the FLAC 3D numerical simulation of a large slope with weak structure plane in the three Gorges Reservoir area is carried out. Its stability under static force and dynamic response process and instability mechanism under earthquake action are studied respectively. The failure process of rock slope under earthquake is analyzed, and the conclusion that weak structure has great influence on slope dynamic characteristics is obtained. The strength reduction method is used to calculate the stability safety factor of the slope under static and seismic conditions. 4 according to the influencing factors of slope stability, combined with the characteristics of engineering geological conditions of a large slope with weak structural plane in the three Gorges Reservoir area. The risk factors of the slope are identified and the indexes affecting the slope stability are determined, including geology (geological structure and rock and soil quality), slope structure, earthquake, hydrological (rainfall and groundwater) conditions and human activities. The risk analysis of slope is carried out by risk factor evaluation table. By comparing the risk analysis results with the FLAC 3D simulation results, it is proved that the slope safety factor has exceeded the safety range under the earthquake action.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU457
[Abstract]:Under the action of earthquake, the consequences of rock slope instability and destruction are often very serious, which results in great loss to the property safety of people and countries. Especially after Wenchuan earthquake, people pay more and more attention to landslide instability caused by earthquake. Many small earthquakes occurred when the three Gorges Dam was storing water. How much influence these earthquakes have on the long-term stability of the slope in the reservoir area is also a problem that people pay close attention to. Based on the project of National Natural Science Foundation (41372356), this paper makes a systematic and in-depth study on the stability and risk of rock slope under earthquake by using the methods of theoretical analysis and numerical simulation. The main research work and results are as follows: 1 based on the examples of homogeneous rock slope and soft intercalated rock slope, the instability criterion conditions of strength reduction method are fully discussed. By comparing several typical instability criteria to obtain the safety factors of different slope stability, the criteria for the convergence of displacement / velocity time-history curves at key points are determined. The dynamic safety factor of the slope is obtained by combining the criterion with the dynamic strength reduction method. 2 the strength parameters, slope height and slope degree of the rock slope are discussed. The influence of amplitude and frequency of seismic wave and parameters of weak structural plane on the stability of rock slope. The results show that increasing the strength parameters of the slope is beneficial to the stability of the slope, the angle of internal friction has more influence on the stability of the slope than the cohesive force, and the coefficient of stability safety decreases with the increase of the slope height and gradient. The safety factor decreases with the increase of the amplitude and frequency of the seismic wave, and the stability of the slope is greatly affected by the weak structure. 3 the FLAC 3D numerical simulation of a large slope with weak structure plane in the three Gorges Reservoir area is carried out. Its stability under static force and dynamic response process and instability mechanism under earthquake action are studied respectively. The failure process of rock slope under earthquake is analyzed, and the conclusion that weak structure has great influence on slope dynamic characteristics is obtained. The strength reduction method is used to calculate the stability safety factor of the slope under static and seismic conditions. 4 according to the influencing factors of slope stability, combined with the characteristics of engineering geological conditions of a large slope with weak structural plane in the three Gorges Reservoir area. The risk factors of the slope are identified and the indexes affecting the slope stability are determined, including geology (geological structure and rock and soil quality), slope structure, earthquake, hydrological (rainfall and groundwater) conditions and human activities. The risk analysis of slope is carried out by risk factor evaluation table. By comparing the risk analysis results with the FLAC 3D simulation results, it is proved that the slope safety factor has exceeded the safety range under the earthquake action.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU457
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