【摘要】：黃土崩塌的危害是眾所周知的,但有效防治一直是非常棘手的,這里面的關(guān)鍵瓶頸就是其機(jī)理問題。為了探索解決這一問題,擬結(jié)合西安法華寺黃土崩塌災(zāi)害實(shí)例進(jìn)行災(zāi)害孕育、發(fā)展、變形、破壞全過程研究,定量討論黃土崩塌災(zāi)害形成-運(yùn)動(dòng)機(jī)理,為黃土崩塌災(zāi)害防治服務(wù),主要得到以下四點(diǎn)研究成果:(1)針對(duì)法華寺黃土崩塌,提出了影響法華寺黃土崩塌的內(nèi)因及外因。內(nèi)因包含坡體形態(tài)、坡體結(jié)構(gòu)、植被作用;外因包含降雨作用、地震作用、工程活動(dòng),為法華寺黃土崩塌機(jī)理研究奠定基礎(chǔ)。(2)針對(duì)法華寺黃土崩塌,提出了三種形成機(jī)理。①暴雨?duì)顟B(tài)崩塌形成機(jī)理:雨水入滲、富集-裂隙擴(kuò)張、充水-破裂面浸潤(rùn)、破裂面貫通-崩塌發(fā)生。②地震狀態(tài)崩塌形成機(jī)理:地震力作用-土體剪斷解體-獲得初速度-產(chǎn)生運(yùn)移-崩塌發(fā)生。③工程活動(dòng)狀態(tài)崩塌形成機(jī)理:工程活動(dòng)作用-破壞應(yīng)力平衡-降雨或振動(dòng)作用-破裂面貫通-崩塌發(fā)生。(3)提出了法華寺黃土崩塌“變形-傾倒-墜落-堆積”的運(yùn)動(dòng)機(jī)理。闡釋了各階段崩塌體特征。①后緣裂隙變形階段:在重力、頂部建筑物及其他外力作用下,坡頂面出現(xiàn)不均勻沉降,產(chǎn)生拉張裂隙。②傾倒階段:當(dāng)裂隙充水時(shí),靜水壓力迅增導(dǎo)致下滑力矩驟增,崩塌體在破裂面底端發(fā)生傾倒運(yùn)動(dòng)。③墜落階段:崩塌體重心移出斜坡之后,脫離母體向下墜落,其過程為斜下拋運(yùn)動(dòng)。④堆積階段:崩塌體經(jīng)墜落后,撞擊地面產(chǎn)生危害。并建立了各階段運(yùn)動(dòng)方程。(4)基于法華寺黃土崩塌災(zāi)害的運(yùn)動(dòng)過程認(rèn)識(shí),建立崩塌體地質(zhì)模型,借助離散元程序?qū)Ρ浪w“變形-傾倒-墜落-堆積”的全過程進(jìn)行數(shù)值模擬,確定暴雨?duì)顟B(tài)、暴雨+地震狀態(tài)崩塌體影響范圍模擬值,通過對(duì)比發(fā)現(xiàn),暴雨+地震狀態(tài)崩塌體的影響范圍模擬值與影響范圍理論值、實(shí)際值較為接近。
[Abstract]:The harm of loess collapse is well known, but effective prevention and cure is always very difficult, the key bottleneck is its mechanism. In order to solve this problem, it is proposed to study the whole process of disaster inoculation, development, deformation and destruction, and discuss quantitatively the formation-movement mechanism of loess collapse disaster. For the prevention and control of loess collapse, the following four main research results are obtained: (1) aiming at the loess collapse in Fahusi, the internal and external factors affecting the collapse are put forward. Internal causes include slope shape, slope structure and vegetation. The external causes include rainfall action, earthquake action and engineering activities, which lay a foundation for the study of the collapse mechanism of the Loess in the Fahua Temple. (2) three kinds of formation mechanisms are put forward for the collapse of the Loess in Fahashi. 1 the formation mechanism of collapse in the rainstorm state: Rain Water infiltration, Enrichment-fracture expansion, water filling-fracture surface infiltration, 2 formation mechanism of earthquake state collapse: seismic force action-soil shear disintegration-obtaining initial velocity-generating migration-occurrence of collapse. 3 formation mechanism of engineering active state collapse: engineering activity Action-failure stress balance-rainfall or vibration-fracture surface transfixion-collapse. (3) the movement mechanism of "deformation-toppling-falling-stacking" of Loess collapse in Fahua Temple is put forward. The characteristics of collapse body in each stage are explained. 1 the deformation stage of fracture in the rear edge: under the action of gravity, top building and other external forces, uneven settlement occurs on the top of the slope, resulting in tensile fissure. 2 the collapse stage: when the crack is filled with water, The rapid increase of hydrostatic pressure results in a sharp increase in the sliding torque, and the collapse body collapses at the bottom of the fracture surface. 3 falling stage: after the collapse body center of gravity is moved out of the slope, the collapse body falls down from the parent body. The process is oblique throwing movement. 4 stacking stage: after falling, the collapse will cause harm to the ground. The equations of motion of each stage are established. (4) based on the understanding of the movement process of the loess collapse disaster in Fahusi, the geological model of the collapse body is established. With the help of discrete element program, the whole process of deformation, toppling, falling and accumulation of collapse body is numerically simulated, and the simulation value of the influence range of collapse body in heavy rain state and storm earthquake state is determined. The simulated values of the influence range of the collapses in the torrential rain state are close to the theoretical values of the influence range, and the actual values are close to those of the theoretical values.
【學(xué)位授予單位】：西安科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：P642.21

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