丹巴县中路乡滑坡群形成机制及现状变形破坏特点

发布时间：2018-04-17 19:32

本文选题：滑坡群 + 形成机制　；参考：《西南交通大学》2017年硕士论文

【摘要】：丹巴县中路乡滑坡群位于中路乡小金河左岸斜坡,基本沿岸坡方向展布,共有大大小小共9个滑坡。近年来滑坡群变形破坏加剧,造成中路乡公路下错,滑坡附近房屋开裂,农田滑动毁坏,以及大量的局部垮塌,对中路乡村民的生命财产安全形成极大隐患,对通乡公路的正常交通造成严重威胁,如果滑坡整体下滑甚至会堵塞小金河河道,后果不堪设想。本文通过现场勘查,分析了中路乡滑坡群空间分布、发育特征、形成原因及滑动模式。然后对区内典型滑坡进行详细的研究,判断它们现在的变形破坏机理,并使用Flac3D数值模拟软件模拟了典型滑坡的变形破坏机制,最后采用不平衡推力法定量计算了典型滑坡的稳定性。本文主要的研究内容和成果如下:(1)根据野外调查结果并结合相关文献,认为中路乡滑坡群是存在位于F1断层上盘和下盘两种发育模式的滑坡群,位于F1断层上盘的滑坡数量较多,滑动模式为牵引式崩滑,变形破坏特征较小;而位于F1断层下盘的滑坡数量少,滑动模式为推移式,变形破坏特征明显。通过分析滑坡形成的各种内外因,得出区内坡体破坏模式为下盘岩土体顺层滑动牵引上盘岩土体崩滑;上盘滑坡多发育在基岩陡崖后方,受到下方基岩失稳或其他因素诱发滑动,下盘滑坡主要为早期岸坡崩滑后形成的堆积体,在外界因素诱发下滑动。(2)位于断层下盘的滑坡近年来滑动明显,个别滑坡已经整体滑动。通过对典型滑坡波色龙滑坡的研究,认为主要是在受到2012年公路开挖影响导致坡体应力重新调整,坡体出现拉张裂缝,坡脚产生塑性变形,随后而至的强降雨诱发了波色龙古滑坡的部分复活,数值模拟结果也印证了这种判断,在坡体开挖前暴雨工况滑坡主要为浅层滑动,开挖后暴雨工况的滑坡整体发生滑动。(3)位于断层上盘的滑坡危害较小,但是近年来变形也有所加剧。通过对典型滑坡三家寨滑坡的研究认为由于前缘的临空和近年来暴雨侵袭,导致三家寨滑坡前缘变形加剧,但是滑坡后部弱变形区变形特征不明显,Flac3D数值模拟结果显示在暴雨工况下前缘主滑方向位移较大,而后缘则以竖直方向位移为主,既表现为下错变形,这与滑坡实际情况一致。(4)对两个典型滑坡运用不平衡推力法进行定量分析结果显示,波色龙滑坡在天然工况下基本稳定,在暴雨和地震工况下为欠稳定;三家寨滑坡在天然工况下为稳定状态,暴雨和地震工况下为稳定～欠稳定,但是其前缘的次级滑面在暴雨工况下为不稳定,地震状态下为欠稳定。所以总体上F1断层上盘滑坡稳定性好于F1断层下盘滑坡。
[Abstract]:Danba County Zhongluxiang landslide group is located on the left bank slope of small Jin He in Zhonglu Township, with a total of 9 landslides, large and small, in the direction of the basic coastal slope.In recent years, the deformation and destruction of the landslide group has intensified, resulting in the dislocation of the highway in Zhonglu Township, the cracking of houses near the landslide, the sliding destruction of farmland, and a large number of local collapses, which pose a great hidden danger to the life and property safety of the villagers in Zhonglu Township.It poses a serious threat to the normal traffic of Tongxiang Highway, and if the landslide as a whole will even block the channel of Little Jin He, the consequences will be unthinkable.In this paper, the spatial distribution, developmental characteristics, formation cause and sliding mode of Zhongluoxiang landslide group are analyzed by on-the-spot investigation.Then the typical landslide in the area is studied in detail to judge their current deformation and failure mechanism, and the deformation and failure mechanism of typical landslide is simulated by using Flac3D numerical simulation software.Finally, the stability of typical landslide is calculated by unbalanced thrust method.The main research contents and results of this paper are as follows: (1) based on the field investigation results and related literature, it is considered that the Zhongluxiang landslide group is a landslide group located in the upper and lower face of F1 fault.The number of landslides located in the upper face of F1 fault is more, the sliding mode is traction type, and the deformation and failure characteristics are smaller, while the number of landslides in the lower face of F1 fault is less, the sliding mode is bedded, and the characteristics of deformation and failure are obvious.Through the analysis of various internal and external causes of landslide formation, it is concluded that the failure mode of slope body in this area is the down-wall rock and soil mass sliding along the layer, and the upper wall landslide is mostly developed behind the bedrock cliff.The slide induced by the instability of the underlying rock or other factors shows that the downboard landslide is mainly an accumulation formed after the early bank slope collapse and slips under external factors) the landslide located in the fault footwall has been sliding obviously in recent years.Individual landslides have slipped as a whole.Through the study of typical landslide Boxelong landslide, it is considered that the stress of slope body is readjusted due to the influence of highway excavation in 2012, the slope body appears tensile cracks, and the slope foot produces plastic deformation.The subsequent heavy rainfall induced the partial resurrection of the Boselong landslide. The numerical simulation results also confirmed this judgment. Before the slope was excavated, the landslide was mainly a shallow slide.The landslide in the upper face of the fault is less harmful, but the deformation is also aggravated in recent years.Through the study of the typical landslide, Sanjiazhai landslide, it is believed that the front deformation of Sanjiazhai landslide is aggravated because of the front edge of the landslide and the heavy rain in recent years.However, the deformation characteristics of the weak deformation area at the back of the landslide are not obvious. The numerical simulation results of Flac3D show that the main slip direction of the front edge is larger under the heavy rain condition, and the vertical direction displacement is the main displacement in the back edge of the landslide.The results of quantitative analysis of two typical landslides by unbalanced thrust method show that the Boxelong landslide is basically stable under natural conditions and unstable under heavy rain and earthquake conditions.Sanjiazhai landslide is stable under natural condition, stable ~ unsteady under rainstorm and earthquake, but its secondary slip surface is unstable under rainstorm condition and unsteady under earthquake condition.Therefore, on the whole, the stability of the upper side landslide of F1 fault is better than that of F1 fault downboard landslide.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

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