【作者】 王者涛；

【导师】 沈军辉；

【作者基本信息】 成都理工大学 ， 地质工程， 2010， 硕士

【摘要】 桅杆梁不稳定斜坡位于四川省广元市青川县主城区西南部,主要由3个老滑坡体和3个倾倒变形体组成。倾倒变形体表部薄板状千枚岩倾倒弯曲变形强烈,5?12汶川特大地震引起倾倒变形体拉裂变形强烈,圈弧状裂缝拉开15～20cm,最大下错量达30cm,对坡下城区居民的生命财产和坡顶古刹宝莲寺安全构成极大威胁。因此,研究其变形破裂机制及稳定性,进而提出防治措施具有重要的实践和理论意义。本文在桅杆梁不稳定斜坡的基本地质条件、斜坡岩体结构、变形破裂迹象等研究基础上,对斜坡的形成演化机制及变形破坏模式进行了分析,采用UDEC二维离散元软件对边坡的变形破坏机制进行了模拟;运用刚体极限平衡理论对边坡的稳定性进行了计算与评价,进而研究了不稳定斜坡的防治措施。取得了如下主要成果:(1)斜坡为千枚岩组成的陡倾顺向坡,其变形破裂机制为倾倒弯曲-拉裂型。不稳定斜坡由3个倾倒变形体和3个由倾倒变形发展成的老滑坡组成。结合斜坡的形成演化,分析了斜坡倾倒弯曲一拉裂变形失稳的过程。(2)5·12汶川特大地震造成不稳定斜坡不同程度的变形破裂,主要具有如下特征:地震对桅杆梁不稳定斜坡的作用主要表现在地震波对坡体的振荡作用,在地震波作用下坡体上的变形破裂特征主要以圈弧状地震裂缝为主。受坡体结构影响,地震裂缝多沿发生明显倾倒弯曲变形的基岩变形体边界呈圈弧状发育,而老滑坡体的边界及其内部裂缝较少发育;除此之外,地震裂缝的分布受地形条件影响较大。由于地震波震动作用及其动响应在坡肩、坡顶一带的放大作用,导致坡顶一带的1#、2#和3#变形体的地震裂缝尤为发育,而坡体中部的老滑坡体与其相比之下则地震裂缝发育较少;2#和3#变形体虽同处于坡顶一带,但由于高程差异,2#变形体变形破裂迹象尤为显著。(3)采用UDEC二维离散元软件对斜坡的变形过程进行数值模拟,分别从位移矢量及速度矢量分析地震状况下在不同计算步时的变形特征,研究斜坡的形成演化过程及其变形破坏模式。结果表明,在地震作用下,斜坡岩体倾倒-弯曲变形,顶部产生垂直于岩层面拉裂破坏的破坏模式。(4)定性分析结合刚体极限平衡法(传递系数法)稳定性计算结果表明,老滑坡体稳定系数均大于1.15,处于稳定状态。3#变形体在各工况下处于稳定或基本稳定状态,但不满足一级边坡的安全标准;1#、2#变形体稳定性天然和暴雨工况下稳定系数均大于1.05,坡体处于基本稳定状态,但在地震工况下稳定系数小于1.05,处于欠稳定状态,不满足一级边坡的安全标准。(5)根据不稳定体结构、变形破坏机制、破坏模式及稳定性状况等,提出了以预应力锚索格构(竖梁)为主的防治措施,并进行了支护设计。更多还原

【Abstract】 Weiganliang unstable slopes in the southwest of Qingchuan County, Guangyuan City, Toppling the Department of sheet-like surface dumping of bending phyllite strong, 5 ? 12 Wenchuan earthquake deformation and shape deformablelandslide strong, circle arc-shaped crack opened 15 ~ 20cm, the largest on the wrong volume of 30cm, posing a serious threat the people behind the slope and to the Po Lin Temple on the top of the hill. Therefore, to study the deformation and fracture mechanism and stability, and to make prevention and control measures have important practical and theoretical significance.In this paper, the Weiganliang unstable slopes of the basic geological conditions, slope rock mass structure, signs of deformation and fracture of the basis of such studies on mechanism of formation and evolution of slope failure modes were analyzed using two dimensional discrete element code UDEC slope deformation and failure mechanism of the simulation; using rigid body limit equilibrium theory to calculate the slope stability and evaluation, and study the unstable slope mitigation measures. Main results obtained are as follows:(1) The slope is the steep dip slope,composed of phyllite. The deformation and fracture mechanisms for the dumping bent - fracturing. Unstable slopes from the three overturned deformation and three from the dumping of old landslide deformation into the composition. Combination of slope formation and evolution, analysis of the slope or bent shape of a tensile failure of the process of fission.(2) 5 ? 12 Wenchuan earthquake caused unstable slopes varying degrees of deformation and fracture, primarily with the following characteristics: Earthquake on the role of the Weiganliang unstable slopes mainly in seismic oscillation effect on the slope. Seismic waves in the slope of the deformation and fracture characteristics of cracks mainly to the earthquake, seismic cracks at the curved growth ring. Affected by the slope structure, circle arc-shaped crack earthquakes over the border along the development of deformed bedrock, that showed significantly deformed rock dumping deformation. The old landslide boundaries and internal cracks in less developed;In addition, the distribution of crack earthquakes influenced by the terrain conditions. As the seismic wave motions and the dynamic response of the slope of the shoulder, top of the hill in the vicinity of amplification, resulting in top of the hill in the vicinity of 1 #, 2 # and 3 # deformed crack earthquakes particular development, the central slope compared with the old landslide under the seismic fractures than less; 2 # and 3 # deformed although the same area at the top of the hill, but because of elevation differences between two # signs of deformation and fracture deformation is particularly significant.(3) UDEC discrete two-dimensional element software on the slope deformation process of numerical simulation, respectively, from the displacement vector and velocity vector of the earthquake conditions in the different steps when calculating the deformation characteristics of the process of its formation and evolution of the slope deformation and failure modes . The results show,Affected by the earthquake,that the slope rock mass dumping-bending at the top level generated perpendicular to the tensile failure of rock failure mode.(4) Qualitative analysis combined with rigid body limit equilibrium method (transfer coefficient) stability calculation results show that the old landslide stability factor greater than 1.15, is stable. 3 # deformed body in the condition in a stable or stable state, but does not meet the safety standards of a slope; 1 #, 2 # Block stability of natural and heavy rain condition stability factor greater than 1.05, slope body is in stable condition, but stable condition in the seismic coefficient is less than 1.05, is less stable, does not meet the safety standards of a slope.(5) According to the unstable structure, deformation and failure mechanisms, failure modes and the stability of the status, put forward a prestressed anchor rope lattice (vertical beam)-based control measures, and had support design.更多还原