贵州省印江县革底滑坡成因机制研究
发布时间：2018-10-20 18:54
【摘要】：革底滑坡位于贵州省铜仁市印江县木黄镇,受暴雨作用影响,于2014年7月17日凌晨4时30分,发生大规模整体滑移形成小型堰塞湖。滑坡发育于由泥灰岩夹页岩组成的顺层缓倾结构边坡中,滑坡发生前,自然斜坡坡度较缓约15°。岩体中发育有层间软弱夹层,滑坡运动过程中不同部位表现出不同的运动残留特征。因此,这种坡度缓的缓倾结构滑坡运动特征研究一定的意义。本文通过详细的野外地质调查,在查明滑坡地质环境条件的基础上,建立了革底滑坡地质结构模型,在此基础上采用二维和三维离散元方法相结合研究了滑坡的运动特征,综合分析了革底滑坡的成因机制及演化过程。取得的主要成果如下:(1)革底滑坡发育于夹有泥质软弱夹层的顺层缓倾边坡中,坡体的地层岩性主要为奥陶系下统大湾组泥灰岩,岩层产状为N4°E/NW∠16°,在泥灰岩中夹有两条泥质软弱夹层。滑坡前缘呈趾状,高程范围850~890m,后缘近弧形,高程为1020~1040m,最大高差约190m。滑坡堆积体宽度约500m,纵向长度约750m。滑坡坡度为10°~48°,下缓上陡,中部出露假基岩,前缘形成堆积高台,堵塞河道,形成堰塞湖,主滑方向为282°,滑坡体积约为200万m3,滑动距离数百米。(2)滑坡的变形破坏迹象主要表现为后缘拉裂及滑体的整体顺层滑移。滑坡后缘分布多条拉裂缝,上游侧滑坡边界后缘经过革底6组房屋聚集区,前缘经过村民耕地;下游侧边界后缘出露的泥灰岩陡壁可见明显擦痕,中部边界树木茂密,原本向斜坡底部滑移的岩体,在这里表现为岩层上翘,裂隙沿结构面发育,边界在坡脚附近出现在村民耕地中。根据现场测绘和高密度电法物理探测方法分析结果,革底滑坡的滑面深度为1m~40m,最深处位于坡体顶部,在物探剖面中有大量的空洞形成,表明堆积体中部分布有大量的裂缝。(3)采用离散元方法,研究革底滑坡的变形破坏过程和滑坡的运动特征。初期,斜坡顶部出现拉裂破坏,坡脚出现位移;接着中部和后缘浅表层的坡体出现分解滑移现象,后缘的裂缝发育较深,并开始出现拉陷槽,而前缘坡体的裂缝也贯通至滑面,导致前缘的坡体也开始发生解体滑移的现象,同时后缘的拉陷槽高差达到15m;最终,坡体整体分解滑移。(4)革底滑坡的变形破坏机制为滑移-拉裂式整体滑坡,由于滑体运动速度不同在局部形成滑移-弯曲现象。将变形破坏过程分为4个阶段:第一阶段,泥质软弱夹层的力学强度降低,导致坡体稳定性降低,坡脚位置的岩体滑出;第二阶段,斜坡中部和上部的泥灰岩中优势发育的结构面L1形成裂缝,并沿着结构面向坡表发育;第三阶段,在斜坡上部坡表发生下陷现象,形成后缘边界,岩体发生向后的倾倒变形现象;第四阶段,坡体完全解体滑移,在前缘堆积并堵塞了河流,形成了堰塞湖。
[Abstract]:GE Di landslide, located in Muhuang Town, Injiang County, Tongren City, Guizhou Province, was affected by heavy rain. At 04:30 on July 17, 2014, a large scale whole slip formed a small barrier lake. The landslide is developed in the bedding gently inclined slope composed of mudstone and shale. The slope of the natural slope is about 15 掳slower before the landslide occurs. There is a weak intercalation in the rock mass, and different parts of the landslide show different movement residual characteristics. Therefore, it is of certain significance to study the landslide movement characteristics of this gently inclined structure. On the basis of detailed field geological investigation and geological environment conditions of landslide, the geological structure model of Gangdi landslide is established. On the basis of this model, the movement characteristics of landslide are studied by combining 2D and 3D discrete element method. The genetic mechanism and evolution process of the Gangdi landslide are analyzed synthetically. The main results obtained are as follows: (1) the Grady landslide developed in the bedding gently inclined slope with muddy weak intercalation, and the stratigraphic lithology of the slope body is mainly limestone of Ordovician Lower Dawan formation. The rock formation is N4 掳E/NW ~ 16 掳, and there are two muddy weak intercalations in the marl. The front edge of the landslide is digitally shaped, with a height range of 850 ~ 890 m, and the posterior edge is nearly arcuate, with a height of 1020 ~ 1040 m, and the maximum height difference is about 190 m. The width of landslide accumulation is about 500m and the longitudinal length is about 750m. The slope of the landslide ranges from 10 掳to 48 掳. The slope of the landslide is 10 掳~ 48 掳, the lower slope is gentle and steep, the central part of the landslide is exposed to pseudo-bedrock, the front edge forms an accumulation platform, the channel is blocked, and a barrier lake is formed. The main slip direction is 282 掳, the volume of landslide is about 2 million m3, and the sliding distance is several hundred meters. (2) the signs of deformation and failure of the landslide are mainly shown as follows: the back edge tension crack and the whole bedding slip of the sliding body. There are many pull cracks in the back edge of the landslide, the back edge of the upper side of the landslide passes through 6 groups of housing accumulation areas, the front edge passes through the villager's cultivated land, the steep wall of the mudstone exposed from the back edge of the downstream side boundary can be seen obvious scratches, and the middle boundary is dense with trees. The rock mass which originally slid to the bottom of the slope is shown here as the rock layer upwardness, the fissure develops along the structural plane, and the boundary appears near the slope foot in the villager cultivated land. According to the results of field mapping and high-density electrical physical detection, the depth of the sliding surface of the Grady landslide is 1 m ~ 40 m, the deepest is located at the top of the slope, and a large number of voids are formed in the geophysical profile. It shows that there are a large number of cracks in the middle of the accumulation body. (3) the deformation and failure process and the movement characteristics of the landslide are studied by using the discrete element method. At the beginning, the top of the slope appeared tensile fracture and the foot of the slope was displaced.Then, the slope body in the middle and the shallow surface of the rear edge appeared the phenomenon of decomposition and slip, and the cracks in the back edge developed deeper, and began to appear the drawing trough, and the cracks in the front slope body also reached the slip surface. The slope body on the leading edge also began to disintegrate and slip, at the same time, the height difference of the pull trough in the back edge reached 15 m. Finally, the slope body was decomposed and slippage. (4) the deformation and failure mechanism of the leathery landslide was the slipping-pull type whole landslide. Due to the different velocities of the sliding body, the slip-bending phenomenon is formed locally. The process of deformation and failure is divided into four stages: in the first stage, the mechanical strength of the muddy weak intercalation decreases, which results in the stability of the slope body reduced and the rock mass at the foot of the slope slide out; in the second stage, In the middle and upper part of the slope, the dominant structural plane L1 formed a crack and developed along the structure facing the slope surface. In the third stage, the subsidence phenomenon occurred in the upper slope surface of the slope, forming the boundary of the back edge. In the fourth stage, the slope body completely disintegrates and slips, accumulates and blocks the river in the front edge, and forms the barrier lake.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.22
本文编号：2284081
[Abstract]:GE Di landslide, located in Muhuang Town, Injiang County, Tongren City, Guizhou Province, was affected by heavy rain. At 04:30 on July 17, 2014, a large scale whole slip formed a small barrier lake. The landslide is developed in the bedding gently inclined slope composed of mudstone and shale. The slope of the natural slope is about 15 掳slower before the landslide occurs. There is a weak intercalation in the rock mass, and different parts of the landslide show different movement residual characteristics. Therefore, it is of certain significance to study the landslide movement characteristics of this gently inclined structure. On the basis of detailed field geological investigation and geological environment conditions of landslide, the geological structure model of Gangdi landslide is established. On the basis of this model, the movement characteristics of landslide are studied by combining 2D and 3D discrete element method. The genetic mechanism and evolution process of the Gangdi landslide are analyzed synthetically. The main results obtained are as follows: (1) the Grady landslide developed in the bedding gently inclined slope with muddy weak intercalation, and the stratigraphic lithology of the slope body is mainly limestone of Ordovician Lower Dawan formation. The rock formation is N4 掳E/NW ~ 16 掳, and there are two muddy weak intercalations in the marl. The front edge of the landslide is digitally shaped, with a height range of 850 ~ 890 m, and the posterior edge is nearly arcuate, with a height of 1020 ~ 1040 m, and the maximum height difference is about 190 m. The width of landslide accumulation is about 500m and the longitudinal length is about 750m. The slope of the landslide ranges from 10 掳to 48 掳. The slope of the landslide is 10 掳~ 48 掳, the lower slope is gentle and steep, the central part of the landslide is exposed to pseudo-bedrock, the front edge forms an accumulation platform, the channel is blocked, and a barrier lake is formed. The main slip direction is 282 掳, the volume of landslide is about 2 million m3, and the sliding distance is several hundred meters. (2) the signs of deformation and failure of the landslide are mainly shown as follows: the back edge tension crack and the whole bedding slip of the sliding body. There are many pull cracks in the back edge of the landslide, the back edge of the upper side of the landslide passes through 6 groups of housing accumulation areas, the front edge passes through the villager's cultivated land, the steep wall of the mudstone exposed from the back edge of the downstream side boundary can be seen obvious scratches, and the middle boundary is dense with trees. The rock mass which originally slid to the bottom of the slope is shown here as the rock layer upwardness, the fissure develops along the structural plane, and the boundary appears near the slope foot in the villager cultivated land. According to the results of field mapping and high-density electrical physical detection, the depth of the sliding surface of the Grady landslide is 1 m ~ 40 m, the deepest is located at the top of the slope, and a large number of voids are formed in the geophysical profile. It shows that there are a large number of cracks in the middle of the accumulation body. (3) the deformation and failure process and the movement characteristics of the landslide are studied by using the discrete element method. At the beginning, the top of the slope appeared tensile fracture and the foot of the slope was displaced.Then, the slope body in the middle and the shallow surface of the rear edge appeared the phenomenon of decomposition and slip, and the cracks in the back edge developed deeper, and began to appear the drawing trough, and the cracks in the front slope body also reached the slip surface. The slope body on the leading edge also began to disintegrate and slip, at the same time, the height difference of the pull trough in the back edge reached 15 m. Finally, the slope body was decomposed and slippage. (4) the deformation and failure mechanism of the leathery landslide was the slipping-pull type whole landslide. Due to the different velocities of the sliding body, the slip-bending phenomenon is formed locally. The process of deformation and failure is divided into four stages: in the first stage, the mechanical strength of the muddy weak intercalation decreases, which results in the stability of the slope body reduced and the rock mass at the foot of the slope slide out; in the second stage, In the middle and upper part of the slope, the dominant structural plane L1 formed a crack and developed along the structure facing the slope surface. In the third stage, the subsidence phenomenon occurred in the upper slope surface of the slope, forming the boundary of the back edge. In the fourth stage, the slope body completely disintegrates and slips, accumulates and blocks the river in the front edge, and forms the barrier lake.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.22
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