【摘要】：地震作用下,巖質(zhì)邊坡失穩(wěn)和破壞產(chǎn)生的后果往往很嚴重,給人民和國家的財產(chǎn)安全造成重大損失。尤其是汶川地震之后,地震引起的滑坡失穩(wěn)越來越受到人們的重視。三峽大壩蓄水時發(fā)生許多微小地震,這些地震對庫區(qū)邊坡的長期穩(wěn)定性到底有多大影響,也是人們十分關注的問題。本文結(jié)合國家自然科學基金項目(41372356),采用理論分析和數(shù)值模擬等方法,對地震作用下巖質(zhì)邊坡穩(wěn)定性及風險進行了較為系統(tǒng)深入的研究,主要研究工作和成果有:①以均質(zhì)巖質(zhì)邊坡和含軟弱夾層巖質(zhì)邊坡算例為基礎,充分討論強度折減法的失穩(wěn)判據(jù)條件。對比幾種典型的失穩(wěn)判據(jù)得到不同邊坡穩(wěn)定性安全系數(shù)后,確定采用關鍵點位移\速度時程曲線收斂的失穩(wěn)判定標準,并以此標準結(jié)合動力強度折減法求得相應算例邊坡的動力安全系數(shù)。②討論了巖質(zhì)邊坡強度參數(shù)、坡高、坡度、地震波振幅和頻率及軟弱結(jié)構(gòu)面參數(shù)對巖質(zhì)邊坡穩(wěn)定性的影響規(guī)律。結(jié)果表明:提高邊坡強度參數(shù)有利于提高邊坡穩(wěn)定性,內(nèi)摩擦角比粘聚力對邊坡穩(wěn)定性影響更大;穩(wěn)定性安全系數(shù)隨著坡高和坡度的增大而降低;安全系數(shù)隨地震波振幅及頻率的增大而減小以及軟弱結(jié)構(gòu)面對邊坡穩(wěn)定性影響較大。③對三峽庫區(qū)某大型含軟弱結(jié)構(gòu)面邊坡進行FLAC 3D數(shù)值模擬,分別研究其在靜力下的穩(wěn)定性及地震作用下的動態(tài)響應過程和失穩(wěn)機理。分析巖質(zhì)邊坡在地震作用下的破壞過程,得到軟弱結(jié)構(gòu)面對邊坡動力特性影響較大的結(jié)論。并采用強度折減法求該邊坡在靜力和地震作用兩種工況下的穩(wěn)定性安全系數(shù)。④根據(jù)邊坡穩(wěn)定性影響因素,結(jié)合三峽庫區(qū)某大型含軟弱結(jié)構(gòu)面邊坡的工程地質(zhì)條件特點,對該邊坡進行風險因子的識別,確定影響邊坡穩(wěn)定性的指標主要包括地質(zhì)(地質(zhì)構(gòu)造和巖土體質(zhì)量)、邊坡結(jié)構(gòu)面、邊坡結(jié)構(gòu)、地震、水文(降雨和地下水)條件和人類活動。由風險因子評估表對邊坡進行風險分析。將風險分析結(jié)果與FLAC 3D模擬結(jié)果進行對比,證明邊坡的安全系數(shù)在地震作用下已經(jīng)超過安全范圍。
[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.
【學位授予單位】：重慶大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU457

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