孙家垭滑坡变形特征及稳定性研究

发布时间：2018-05-28 20:14

本文选题：孙家垭滑坡 + 变形特征　；参考：《成都理工大学》2017年硕士论文

【摘要】：本文研究对象为孙家垭滑坡,该滑坡位于四川省广元市旺苍县普济镇,通过对滑坡的现场地质调查,较全面地研究了该滑坡工程地质条件、坡体结构特征、岩土体结构特征以及滑坡变形特征等。运用极限平衡方法对该滑坡各变形体在不同工况下的稳定性进行了分析评价;在深入研究滑坡稳定性的基础上,根据现场实测剖面,运用ANSYS软件建立了滑坡的三维概念模型,再运用FLAC3D程序对提出的概念模型进行数值模拟分析计算。根据对滑坡的详细调查和分析其具体成因、地质情况和现场变形特征,提出了相应的防治措施。得出了以下主要研究成果:(l)通过现场勘查和钻探,查明了孙家垭滑坡属于构造侵蚀剥蚀中山地貌,岩层产状为200°∠16°,滑坡坡向为210°,为一顺层缓倾滑坡;查明了滑坡的基本特征、地层和物质组成,从而将滑坡划分为三个变形区:牵引变形区(A区)、强变形区(B区)、滑覆区(C区)。(2)滑坡体内安装了位移监测系统,可以监测滑坡在x、y两个方向上的位移变化,得到了7月到8月的累计位移—孔深曲线和在累积位移—孔深曲线数据中提取的各钻孔分别在孔深1m、2m、3m、4m、8m和16m时的累计位移随累计时间的变化数据;ZK02和ZK03安装的监测系统被当地居民破坏,因此未得到真实有用的数据;ZK01和ZK04数据较为正常,能够较清晰的观测到滑坡的位移波动段,确定滑坡的滑动面,得出结论为滑坡为浅表层土质滑坡,滑坡A区稳定性比B区稳定性好。(3)野外现场进行双环注水试验,滑坡滑坡表层覆盖物为粉质黏土夹少量碎石和粉质粘土,其渗透系数分别为1.9×10-3cm/s、1.7×10-3cm/s,透水性一般。而下伏基岩为弱透水性的砂岩和泥岩,隔水能力相对较好,这有利于地下水在滑体内富集,对滑坡稳定性不利。(4)根据降雨对滑坡强变形区内拉槽的影响过程,可将该拉槽的形成过程划分为五个阶段:裂缝充水张开阶段—初期短距离拉裂缝启动阶段—裂缝扩张形成拉槽阶段—拉槽进一步蠕变变形阶段—后期拉槽剧烈变形,导致新裂缝产生阶段。(5)用极限平衡性法,计算了孙家垭滑坡在天然、降雨、地震工况下的稳定性系数,结果表明:天然工况下,滑坡是稳定的,降雨工况下滑坡是欠稳定—基本稳定的,地震工况下,滑坡是欠稳定的。(6)根据滑坡体变形特征以及变形的影响因素分析,采用FLAC3D数值模拟对孙家垭滑坡在天然、降雨和地震工况下的变形机制进行了数值分析。计算分析结果表明:①在天然工况下,滑坡稳定系数为1.25,最大滑动距离约为4.8cm,变形迹象不明显,处于稳定状态。②在降雨工况下,滑坡稳定性系数为1.09,最大位移约为13cm,局部形成了贯通的塑性变形区,未形成剪应变增量贯通带,局部可能发生变形破坏,说明滑坡处于基本稳定状态。③在地震工况下,滑坡滑坡的稳定性系数为1.01,最大位移约为19cm,形成了几乎贯通的位移变化区,说明了滑坡在地震作用时表层土体受地震力作用变得松动,滑动的可能性较大,说明滑坡是欠稳定的。(7)根据滑坡的地理位置、地形地貌、变形特征和稳定性状况,对滑坡防治提出了几点措施建议:(1)削方减载和拉槽回填;(2)地表开挖导槽排水;(3)修建挡土墙支挡。
[Abstract]:The object of this study is the Sun Jia Ya landslide, which is located in Puji Town, Wangcang County, Guangyuan, Sichuan. Through the field geological investigation of the landslide, the engineering geological conditions of the landslide, the structure characteristics of the slope, the characteristics of the rock and soil structure and the characteristics of the landslide deformation are thoroughly studied. The stability of the same working condition is analyzed and evaluated. On the basis of studying the stability of the landslide, the three-dimensional conceptual model of the landslide is established by using the ANSYS software, and the FLAC3D program is used to simulate and analyze the proposed conceptual model. The detailed investigation and analysis of the landslides is based on the detailed investigation and analysis of the causes. The following main research results are obtained: (L) through field exploration and drilling, it is found that the Sun Jia Ya landslide belongs to the tectonic erosion and erosion of Zhongshan geomorphology, the rock formation is 200 degrees 16 degrees, the landslide slope is 210 degrees, and it is a gentle dip slide landslide, and the basic characteristics of the landslide are found out. The layer and the material composition are divided into three deformation zones: the traction deformation zone (A area), the strong deformation zone (B region) and the slip zone (C area). (2) the displacement monitoring system is installed in the landslide body, which can monitor the displacement changes in the two directions of the landslide in the X and Y directions, and the cumulative displacement hole depth curve and the cumulative displacement depth curve from July to August are obtained. The cumulative displacement of each borehole extracted from the data in the hole depth 1m, 2m, 3M, 4m, 8m and 16m changes with the cumulative time. The monitoring system installed by ZK02 and ZK03 is destroyed by the local residents, so the real useful data are not obtained; ZK01 and ZK04 are more normal, and can clearly observe the displacement fluctuation section of the landslide and determine the landslide. The sliding surface has concluded that the landslide is a shallow surface soil landslide, and the stability of the landslide A area is better than that in the B area. (3) the double ring water injection test in the field is carried out in the field. The surface cover of the landslide and landslide is a small amount of gravel and silty clay, the permeability coefficient is 1.9 x 10-3cm /s, 1.7 x 10-3cm/s, and the permeability is general, but the underlying bedrock is weak. Water permeable sandstone and mudstone have relatively good water isolation ability, which is beneficial to the accumulation of groundwater in the sliding body and is unfavorable to the stability of landslides. (4) according to the influence of rainfall on the internal pulling trough in the strong deformation zone of the landslide, the process of forming the trough can be divided into five stages: the opening stage of the crack filling water and the initial stage of the short distance tensile crack in the initial stage - The crack expansion is formed in the stage of the drawing slot - the further creep deformation stage of the pull trough - the later stage of the tensile trough, which leads to the new crack generation stage. (5) the stability coefficient of the Sun Jia Ya landslide is calculated under the natural, rainfall and earthquake conditions by the limit equilibrium method. The results show that the landslide is stable under the condition of sky natural condition, and the landslide is under the condition of rainfall. Stability basically stable, the landslide is less stable under the earthquake condition. (6) according to the analysis of the deformation characteristics of the landslide body and the influence factors of deformation, the numerical analysis of the deformation mechanism of the Sun Jia Ya landslide under natural, rainfall and earthquake conditions has been carried out by FLAC3D numerical simulation. The calculation and analysis results show that: (1) the landslide stability under natural conditions The coefficient is 1.25, the maximum sliding distance is about 4.8cm, and the deformation sign is not obvious. Under the condition of rainfall, the stability coefficient of the landslide is 1.09, the maximum displacement is about 13cm, the plastic deformation zone is formed in the local area, the shear strain increment perforation zone is not formed, and the local deformation and failure may occur in the local area, indicating that the landslide is in the basic stable shape. In the case of earthquake, the stability coefficient of landslide and landslide is 1.01, the maximum displacement is about 19cm, and the displacement change area which is almost through is formed. It shows that the surface soil of the landslide is loosened when the earthquake action is affected by the earthquake force, and the possibility of sliding is larger. (7) according to the geographical location of the landslide and the topography and geomorphology On the basis of the deformation characteristics and stability conditions, some suggestions are put forward for the prevention and control of landslide: (1) cutting and reducing slots and backfilling; (2) surface excavation guide groove drainage; (3) building retaining wall support.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

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