沐川县堆积层滑坡形成机制研究

发布时间：2018-07-24 17:30

【摘要】：堆积层滑坡是指发生在第四系地层内松散堆积层中的滑坡,其滑体物质一般由崩积、崩坡积物、冲积与崩坡积混合物堆积而成,沐川县覆盖层主要以红层粉质粘土夹碎石构成,其结构松散、孔隙比较大、透水性强,极易在降雨、地震作用下出现破裂变形,降低坡体稳定性。本文在实地调查沐川全域131处滑坡基础之上,选出63处堆积层滑坡作为研究对象。通过对野外资料及其它相关资料收集、整理了各个堆积层滑坡要素总结了滑坡发育分布规律;采用Arcgis软件为滑坡分布规律的研究生成必需图件,并结合室内实验成果,探讨了降雨、地震对滑坡的作用过程,深入研究了区域堆积层滑破变形破坏机制;最后辅以Geo-studio对前期提出的破坏机制进行验证。本文取得的主要成果和创新如下:⑴研究的63处堆积层滑坡,最大特点是坡度主要集中在15°~25°,最大不超过30°,这与其它区域堆积层滑坡差别较大。此外采用最小外接矩形规则,利用各个滑坡长宽比将其平面形态分为横长式、等轴式、纵长式。通过XRD等实验得出其堆积层物质组成主要以蒙脱石类矿物为主、滑体存在三种结构组合。通过调查研究发现其滑动面形态、倾角及滑坡空间展布方向特征明显。⑵区域堆积层滑坡主要着床于构造侵蚀剥蚀低山及河流侵蚀沟谷地貌单元,并且主要受褶皱构造控制,集群性明显,主要分为五渡-利店族群、五指山-沐川族群。滑坡滑动具有明显的时间节点,由于区域地震作用显著,滑坡大都发生于2008年地震之后,并且主要分布在每年的7~8月的雨季时节。因此地震、降雨是该类滑坡失稳的最主要原因。此外堆积层滑坡在在区域三大流域均有分布,但主要分布在马边河流域。⑶降雨、地震的耦合作用能极大的诱发堆积层滑坡失稳。区域63处堆积层滑坡就有54处发育于年降雨量在1300mm~1400mm区域,并且调查结果显示在滑坡失稳前后均伴随有不同强度的降雨。在室内试验基础上,通过分析不同含水量剪应力-剪位移曲线、不同含水量内摩擦角变化曲线、不同含水量黏聚力变化曲线得到含水量改变的敏感性大小为黏聚力内摩擦角。⑷研究区堆积层滑坡成因主要为:地震作用、降雨作用、人类工程活动扰动作用,在此基础之上总结了显著影响堆积层滑坡形成演化进程的4种耦合模式:降雨-重力耦合模式、地震-降雨耦合模式、冲蚀-重力耦合模式、人工扰动-降雨耦合模式。⑸根据堆积层滑坡滑面倾缓情况、滑体物质组成、变形破坏模式对研究区63处堆积层滑坡对号归纳,进行分类得到3大类,7小类,涵盖7种变形破坏模式,分别为:冲蚀-滑移、震动-蠕变、震裂-滑移、塑流-溜滑、蠕变-推移、蠕变-牵引、蠕变-滑移。文章详细阐述了上述7种模式的形成演化过程。⑹利用Geo-studio数值模拟软件对震动-蠕变模式进行模拟,采用QUAKE、SIGMA分析地震作用下堆积层动力响应和裂缝形成,SEEP进行不同降雨雨强和历时作用下的地下位变化。
[Abstract]:The landslide of the accumulative layer refers to the landslide occurring in the loose accumulation of the Quaternary strata. The material of the slide body is usually made up of a mixture of alluvium, alluvium, alluvium and avalanche. The cover layer of Muchuan county is mainly composed of red layer silty clay, and its structure is loose, the pore is large, and the permeability is strong, and it is easily under the action of rainfall and earthquake. In this paper, on the basis of 131 landslides in the whole area of Muchuan, 63 stacked landslides were selected as the research object. Through the collection of field data and other related data, the distribution rules of landslide development were summarized and the distribution rules of landslide distribution were summed up by Arcgis software. The study of the law produces the necessary drawings, and combines the laboratory results, discusses the process of rainfall, the action of the earthquake on the landslide, and deeply studies the failure mechanism of the slippery deformation of the regional accumulation layer. Finally, the failure mechanism of the previous Geo-studio is verified. The main achievements and innovations obtained in this paper are as follows: (1) 63 stacking layers slippery in the study The main feature of slope is that the slope is mainly concentrated at 15 degree ~25 degrees, and the maximum is not more than 30 degrees, which is different from that of other areas. In addition, using the minimum external rectangle rule, the plane shape is divided into length and length type with the length width ratio of each landslide. The material composition of the accumulation layer is mainly montmorillonite through the experiment of XRD. There are three kinds of structure combination of stone minerals. Through investigation and study, it is found that the sliding surface morphology, dip angle and the spatial distribution direction of landslides are obvious. 2. Regional accumulation layer landslides are mainly covered by tectonic erosion and erosion low mountain and river erosion Valley geomorphology unit, and mainly controlled by fold structure. The five Du Li Li group, the Five Fingers Group Muchuan group. The landslide slipping has obvious time nodes. Because of the significant regional earthquake action, the landslides mostly occurred after the 2008 earthquake and mainly distributed in the rainy season of 7~8 months each year. The three major basins are distributed, but mainly distributed in the Marian River Basin. (3) rainfall, the coupling effect of the earthquake can greatly induce the instability of the accumulation layer landslides. There are 54 areas of the 63 accumulation landslides in the region in the 1300mm~1400mm area, and the results show that there are different intensity of rainfall before and after the landslide instability. On the basis of the test, through the analysis of the shear stress shear displacement curves of different water content, the change curve of internal friction angle in different water content, the sensitivity of different water content cohesion curve to the change of water content is cohesion internal friction angle. 4. The main causes of the accumulation layer landslide in the study area are earthquake action, rainfall, human engineering activity disturbance. On this basis, 4 coupling modes are summarized, including rainfall gravity coupling model, earthquake rainfall coupling model, erosion gravity coupling model and artificial disturbance rainfall coupling model. 63 types of accumulation layer landslides are summed up in the study area, which are classified into 3 categories, 7 small classes, covering 7 types of deformation and failure modes, namely: erosion slip, vibration creep, earthquake crack slip, plastic flow slip, creep lapse, creep traction, creep slip. The paper expounds the formation and evolution process of the above 7 modes in detail. The pseudo software is used to simulate the vibration and creep model, and QUAKE, SIGMA is used to analyze the dynamic response and crack formation of the stacking layer under the action of earthquake, and the variation of the underground position under different rainfall intensity and diachronic effect is carried out by SEEP.
【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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