本文關(guān)鍵詞： 危巖 變形破壞機(jī)制 穩(wěn)定性評(píng)價(jià) 斷裂力學(xué) 離散元 貴州赤水　出處：《貴州大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：崩塌是貴州省易發(fā)的地質(zhì)災(zāi)害之一。貴州省赤水市元厚鎮(zhèn)紅層危巖帶位于元厚鎮(zhèn)北部陡崖地帶,大小危巖體(崩塌體)共計(jì)49個(gè),威脅著鎮(zhèn)集內(nèi)居民的人身及財(cái)產(chǎn)安全。本論文在了解國(guó)內(nèi)外研究現(xiàn)狀、收集前人研究資料和現(xiàn)場(chǎng)詳細(xì)勘查的基礎(chǔ)上,強(qiáng)調(diào)了危巖體的地質(zhì)原型現(xiàn)場(chǎng)調(diào)研與地質(zhì)過(guò)程分析,借助離散元程序UDEC對(duì)危巖體的變形破壞過(guò)程進(jìn)行模擬。研究危巖帶變形破壞特征、成因機(jī)制及破壞模式。采用極限平衡理論和斷裂力學(xué)兩種分析法進(jìn)行了研究區(qū)內(nèi)危巖體的穩(wěn)定性評(píng)價(jià)。主要獲得的認(rèn)識(shí)及成果如下:1、研究區(qū)危巖帶所處紅層巖層斜坡,總體呈上陡下緩的地貌特征,從山頂?shù)狡履_表現(xiàn)為三個(gè)臺(tái)階。斜坡坡角75~85°,地層為侏羅系上統(tǒng)蓬萊鎮(zhèn)組(J3p)的泥巖和砂巖互層組合,巖層傾角較小(15°)。高陡的地貌特征為斜坡的變形提供了較好的臨空條件。研究區(qū)內(nèi)發(fā)育3組優(yōu)勢(shì)裂隙,將巖體切割成塊狀并形成明顯的外傾結(jié)構(gòu)面,加劇了巖體的破碎程度,為危巖體的形成及崩塌創(chuàng)造了有利的條件。2、總結(jié)了研究區(qū)危巖帶特征及規(guī)律。危巖帶發(fā)育在層狀巖體斜坡上塑造成峻峭的陡崖地貌,而這種陡峻地貌形態(tài)又能加劇危巖帶發(fā)育過(guò)程,其結(jié)果是使懸崖后退,高度降低,坡地逐漸變緩,危巖的崩塌作用也漸趨消亡。3、劃分了危巖帶變形破壞階段。元厚鎮(zhèn)危巖帶是在不利坡體組合和地質(zhì)結(jié)構(gòu),加之氣候條件綜合作用下形成的,其演化過(guò)程分為6個(gè)階段:初始階段(階段1);河谷下切階段(階段2);差異風(fēng)化階段(階段3);危巖體形成階段(階段4);危巖體變形破壞階段(階段5);崩塌完成階段(階段6)。4、根據(jù)崩塌體結(jié)構(gòu)特征、變形特征、受力狀況和失穩(wěn)方式的不同,將研究區(qū)危巖體破壞模式分為傾倒式和墜落式兩類(lèi),并初步分析了每一種破壞模式的成因機(jī)制。5、建立UDEC離散元數(shù)值模擬模型,模擬在自然和降雨作用下,危巖體的變形破壞演變情況。結(jié)果顯示差異風(fēng)化是危巖帶形成的根本原因,降雨是危巖帶變形加劇和崩塌的誘發(fā)因素。危巖帶變形破壞機(jī)制是:由于差異分化形成初始巖腔及卸荷裂隙,改變坡體應(yīng)力狀態(tài),使其穩(wěn)定性下降,在降雨等其他外界因素下,危巖體崩落。6、采用極限平衡法和斷裂力學(xué)法評(píng)價(jià)結(jié)果得出:分別對(duì)研究區(qū)危巖體在三種情況(天然、暴雨、暴雨+地震)下進(jìn)行穩(wěn)定性計(jì)算,元厚鎮(zhèn)危巖帶目前大部分危巖體處于第四階段成熟期(危巖體形成階段)和第五階段(危巖體變形破壞階段)的孕育期,處于欠穩(wěn)定狀態(tài),建議采取清除+嵌補(bǔ)支撐+錨固+SNS主動(dòng)防護(hù)網(wǎng)的綜合治理方案。
[Abstract]:Collapse is one of the geological hazards easily occurring in Guizhou Province. The Red Strata dangerous Rock Belt of Yuanhou Town, Chishui City, Guizhou Province, is located in the steep cliff zone north of Yuanhou Town, with a total of 49 dangerous rock masses (collapses). This paper, on the basis of understanding the present research situation at home and abroad, collecting the previous research data and site detailed exploration, emphasizes the site investigation and geological process analysis of the geological prototype of the dangerous rock mass. The process of deformation and failure of dangerous rock mass is simulated by means of discrete element program UDEC. The characteristics of deformation and failure of dangerous rock zone are studied. Genetic mechanism and failure mode. The stability evaluation of dangerous rock mass in the study area is carried out by using limit equilibrium theory and two kinds of analysis methods of fracture mechanics. The main knowledge and results obtained are as follows: 1. The red bed rock layer slope located in the dangerous rock belt in the study area is studied. There are three steps from the top of the hill to the foot of the slope. The slope angle is 75 ~ 85 擄, and the formation is the mudstone and sandstone interbedded assemblage of the Jurassic Upper Penglai Zhen formation (J _ 3p). The slope angle is smaller than 15 擄, and the high and steep geomorphology features provide better conditions for slope deformation. Three groups of dominant fractures are developed in the study area, which cut the rock mass into blocks and form obvious extroverted structural planes, thus exacerbating the degree of rock mass fragmentation. This paper creates favorable conditions for the formation and collapse of dangerous rock mass, summarizes the characteristics and laws of dangerous rock zone in the study area. The dangerous rock zone is formed on the slope of layered rock mass into a steep cliff geomorphology. However, the steep geomorphology can aggravate the development process of the dangerous rock belt. As a result, the cliff recedes, the height decreases, and the slope gradually slows down. The collapse of dangerous rock is also gradually dying out, which divides the deformation-failure stage of dangerous rock zone into three stages. The dangerous rock belt in Yuanhuzhen is formed under the combination of unfavorable slope body assemblage and geological structure, as well as the comprehensive action of climatic conditions. The evolution process is divided into six stages: initial stage (stage 1), valley shearing stage (stage 2), differential weathering stage (stage 3), dangerous rock mass formation stage (stage 4), critical rock mass deformation stage (stage 5) and collapse stage (stage 5). (stage 6. 4, according to the structural characteristics of the collapse, According to the difference of deformation characteristics, stress condition and instability mode, the failure modes of dangerous rock mass in the study area are divided into two types: toppling type and falling type, and the cause mechanism of each failure mode is analyzed preliminarily, and the numerical simulation model of UDEC discrete element is established. Under the action of nature and rainfall, the deformation and failure evolution of dangerous rock mass is simulated. The results show that differential weathering is the fundamental reason for the formation of dangerous rock zone. Rainfall is the inducing factor of the deformation and collapse of the dangerous rock zone. The mechanism of deformation and failure of the dangerous rock belt is that the initial rock cavities and unloading cracks are formed due to the differential differentiation, the stress state of slope body is changed and the stability of slope body is decreased, and other external factors such as rainfall, etc. Using limit equilibrium method and fracture mechanics method to evaluate the stability of dangerous rock mass under three conditions (natural, rainstorm, rainstorm earthquake) in the study area. At present, most of the dangerous rock masses in Yuanhuzhen dangerous rock belt are in the gestation period of maturity stage (formation stage of dangerous rock mass) and stage 5th (deformation and failure stage of dangerous rock mass) in 4th stage, and are in an unstable state. It is suggested that the comprehensive treatment scheme of SNS active protection net should be adopted.
【學(xué)位授予單位】：貴州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：P642.2

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本文編號(hào)：1499007