白龙江流域大型滑坡发育特征及成因机制研究

发布时间：2018-04-26 11:14

本文选题：白龙江流域 + 大型滑坡　；参考：《成都理工大学》2017年硕士论文

【摘要】：白龙江流域位于青藏高原与黄土高原之间的过渡区,为斜坡急剧变形带。流域内大型滑坡具有分布范围广、密度大、活动频繁、危害严重等特点。本文基于研究区工程地质环境条件,着重对白龙江大型滑坡发育特征进行分析,对流域内大型滑坡的进行分类,探讨各类型滑坡的控制因素、演化历史及其成因机制并总结归纳出该类型滑坡的地质力学“概念模型”,以期望获得流域内大型滑坡发育特征及成因机制方面的重要理论和对灾害预测、灾害救治方面的实际意义。本文在前人的研究成果、遥感解译、野外调查的基础上,采用统计分析、定性分析、半定量分析、数值模拟等方法,系统地分析和研究白龙江流域大型滑坡的工程地质环境条件、分布规律、发育特征、演化过程、成因机制以及堵江滑坡的分布规律、影响因素、环境效应、复活机制等,可以得出以下结论:(1)流域内大型滑坡具有显著地沿河流水系呈线状分布和沿断裂带呈带状分布的特点;大型滑坡分布对河流岸别无明显选择性;流域内90%以上的大型滑坡分布在距断层距离小于5.0km的范围内,断裂交叉、错列及交汇部位呈现出大型滑坡集中分布的特点;流域内大型滑坡数目(N)与最近断裂的地表破裂面的垂直距离(Dr)满足以下关系:N=113.9e-0.4Dr(R2=0.9553)。(2)流域内大型滑坡主滑方向以NE向、W向为主,但是武都区两水镇至舟曲县腊子口乡一带表现出与断层走向基本一致的特征,即SE向和NW向为主;流域内大型滑坡的滑移距离与滑坡体积有关,随着体积的增大,大型滑坡的运动性摩擦系数呈指数降低,部分大型滑坡表现出强碎屑流特征;流域内大型滑坡的视摩擦角与滑坡体积满足以下关系:f=11.422e-0.472lg(V/m~3)(R2=0.5148)。(3)流域内大型滑坡主要受地形地貌、地层岩性、岸坡结构、断裂构造、新构造运动及地震的影响;1)流域内大型滑坡表现出与高程和微地貌很好的对应关系,大部分大型滑坡分布在1200~2600m(上游2200~2600m、中游1600~2200m、下游1200~1600m)以下的河谷峡谷段,尤其是宽谷向峡谷转折部位;2)流域内软硬相间层状岩岩组最有利于大型滑坡发育,93%以上的大型滑坡与千枚岩、板岩等浅变质岩相关;3)流域内中倾顺向坡最有利于大型滑坡发育,岩层倾角越陡斜坡稳定性越差,顺向坡与含有与坡向基本一致的结构面逆向坡斜坡稳定性差。(4)依据大型滑坡的岩土体类型以及滑面的发育位置可将区内的大型滑坡进一步划分为黄土层内滑坡、黄土接触面滑坡、黄土-基岩滑坡、基岩滑坡等共四大类;同时,结合具体斜坡结构、演化过程、地质力学模式,归纳总结区内大型滑坡的成因机制,黄土层内滑坡的成因机制主要为蠕滑-拉裂;黄土接触面滑坡接触面滑坡的成因机制主要为拉裂-抛射、地震液化-塑性流动、拉裂-溃滑等;黄土-基岩滑坡与基岩滑坡的成因机制主要为滑移-拉裂、拉裂-溃滑、弯曲-拉裂、滑移-倾倒、褶皱翼部控制型、断裂破碎带型等。(5)区内不完全堵江滑坡数量与完全堵江滑坡数量之比约2:1,其形成与分布具有区域性与群发性的特点;地形地貌、地质构造、水动力条件与地震活动等为滑坡堵江的主要影响因素;野外调查表明,草坡滑坡向白龙江上游至武都区桔柑乡段,现至少保存有8处湖相沉积物,沉积物顶面拔河高程普遍在55~70m之间,沉积物主要以粉土、细砂为主,局部可见有卵砾石层;因为未对8处沉积物进行测年,尚不能确定均由草坡滑坡堰塞白龙江形成;基于FLAC-3D数值模拟表明:天然状态下滑坡堆积体的剪应变值较小,堆积体中、后部出现较为明显的剪应变集中带,剪应变增量集中带亦出现在滑坡中后部但其并未贯通整个滑坡堆积体;地震作用下堆积体总位移量与水平位移量均在堆积体中、后部表现为最大值,堆积体后缘及其前缘部位均出现较明显的剪应变集中带,说明地震是导致该滑坡复活的主要因素。
[Abstract]:The white Longjiang basin is located in the transition zone between the Qinghai Xizang Plateau and the Loess Plateau, which is the steep deformation zone of the slope. The large landslides in the basin have the characteristics of wide distribution, large density, frequent activity and serious harm. This paper is based on the engineering geological conditions of the study area, focusing on the analysis of the development characteristics of the large landslides in white Longjiang, and the large-scale landslides in the basin. This paper classifies the landslides, discusses the controlling factors of various types of landslides, the evolution history and its genetic mechanism, and sums up the "conceptual model" of the geological mechanics of this type of landslides, in order to expect to obtain the important theory of the characteristics and mechanism of the large landslides in the basin, the prediction of the disaster and the practical significance of the disaster treatment. On the basis of previous research results, remote sensing interpretation and field investigation, the engineering geological environment conditions, distribution rules, development characteristics, evolution process, genetic mechanism and distribution law of the landslide in the white Longjiang basin are systematically analyzed and studied by means of statistical analysis, qualitative analysis, semi quantitative analysis and numerical simulation. Affecting factors, environmental effects and resurrection mechanisms, we can draw the following conclusions: (1) the large landslides in the basin have the characteristics of linear distribution along the river flow system and the strip distribution along the fault zone; the distribution of large landslides has no obvious selectivity to the river bank; more than 90% of the large landslides in the basin are distributed at the distance from the fault to less than 5.0km. Within the range, the fracture intersection, the fault column and the intersection point show the characteristics of large landslides; the number of large landslides (N) in the basin and the vertical distance (Dr) of the surface rupture surface (Dr) meet the following relationship: N=113.9e-0.4Dr (R2=0.9553). (2) the main sliding direction of the large landslides in the basin is NE and W direction, but the town of Wudu area is two water. The area of La Zi Kou Township in Zhouqu county is basically consistent with the fault trend, that is, SE direction and NW direction. The sliding distance of large landslides in the basin is related to the landslide volume. With the increase of volume, the movement friction coefficient of large landslides decreases exponentially, and some large sliding slopes show strong debris flow characteristics, and large landslides in the basin. The apparent friction angle and the landslide volume meet the following relation: f=11.422e-0.472lg (V/m~3) (R2=0.5148). (3) large landslides in the basin are mainly affected by topography, lithology, bank slope structure, fracture structure, the influence of neotectonic movement and earthquake; 1) the large landslides in the basin show a good correspondence with the elevation and micro landforms, and most of the large landslides In the valley Canyon section below 1200~2600m (upstream 2200~2600m, middle reaches 1600~2200m, downstream 1200~1600m), especially the turning part of the wide valley to the canyon; 2) the soft and hard interphase stratiform rock group is most beneficial to the development of large landslides, and more than 93% of the large landslides are related to the phyllite, the slate and other superficial metamorphic rocks; 3) the middle inclined slope in the basin is the most important. The stability of the steep slope is worse, the stability of the slope is worse. (4) the large landslides in the large landslides can be further divided into landslides in the loess layer, the Loess contact surface landslides, and the Yellow loess. There are four types of soil bedrock landslides and bedrock landslides. At the same time, combined with concrete slope structure, evolution process and geomechanics model, the genetic mechanism of large landslides in the area is summed up. The main cause mechanism of the landslides in the loess layer is creep and crack, and the mechanism of the contact surface landslides on the contact surface of the loess is mainly caused by crack and ejection and liquefaction of the earthquake. The formation mechanism of loess bedrock landslides and bedrock landslides is mainly slip and pull, crack and slip, bend and pull, slip and fall, fold wing control type and fracture fracture zone type. (5) the number of incomplete landslides in the area is about 2:1, and its formation and distribution are regional. The main influence factors of the landform, landform, geomorphology, geological structure, hydrodynamic conditions and seismic activity are the main influencing factors of the landslide, and the field investigation shows that at least 8 lacustrine sediments are preserved at the upper reaches of white Longjiang to the tangerine township of Wudu District, and the top of the sediment top is generally between 55~70m and the sediments are mainly in the sediments. The silt and fine sand are the main parts of the gravel layer. Because the 8 sediments are not measured in 8 places, it is not sure that all of them are formed by the grass slope landslide weir in white Longjiang. Based on the numerical simulation, the shear strain value of the natural state sliding slope is small, and the shear strain increment is obvious in the back part and the shear strain increment in the rear part of the accumulation body. The concentration zone also appears in the back of the landslide but it does not pass through the whole landslide accumulation body. The total displacement and horizontal displacement of the accumulation body are all in the accumulation body under the earthquake action, the rear part shows the maximum value, and the posterior margin and the front edge of the accumulation body appear more obvious shear strain concentrated zone, indicating that the earthquake is the main factor leading to the resurrection of the landslide.

【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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