论文部分内容阅读
汶川强震区地处龙门山区,在深切河谷地貌条件下,地震诱发大量崩塌及滑坡地质灾害,给沿河谷布线的公路造成严重损毁。在调查掌握约6 056 km灾区公路沿线地震崩滑灾害详细资料基础上,根据地质构造、地震烈度进行段落划分,研究分析各段灾害特征及其与地质构造部位、地震烈度、岩性等之间的关系,统计分析各段落灾害点密度及平均规模。提出汶川地震崩滑灾害分区,将受灾区划分为极强烈发育区、强烈发育区、较强烈发育区、中等发育区和弱发育区等5个区域。得出汶川地震崩滑灾害如下发育规律:(1)3条断裂带对崩滑灾害发育的控制作用:前山断裂都江堰—竹园坝段为山前弱发育区和上盘中等～强烈发育区的明显界线,竹园坝NE方向则控制作用减弱;中央主断裂自映秀至东河口段上下盘灾害有显著差异,2个极强烈发育区均位于上盘,且被后山断裂及重要岩性界线所严格限制,东河口NE方向控制作用减弱;后山断裂之茂汶断裂为极强烈发育区和较强烈发育区的明显界线;后山断裂之青川—平武断裂在青川—沙洲段呈现出明显的断层上盘效应。(2)岩性控制作用:不同岩性类别地震崩滑灾害发育程度有显著差异,侵入岩体和灰岩、白云岩类地震地质灾害发育密度最高、平均规模最大,千枚岩类灾害发育密度最低、规模最小,碎屑岩类和砂板岩类介于其间。(3)地貌控制作用:河谷岸坡相对高差越大、地面横坡越陡峻,地震崩滑灾害越发育。陡坡硬岩段为地震崩滑灾害高发区,失稳主要发生在斜坡中上部、陡缓变坡点附近。(4)399条实测地质剖面的统计分析表明,地震诱发崩塌失稳部位坡度一般在40°以上。(5)动力条件下,坡体结构是边坡岩土体变形破坏的控制性因素,土层及强风化层-基岩斜坡、发育外倾结构面斜坡更易失稳。
Wenchuan earthquake area is located in Longmenshan District, in the deep river valley landscape conditions, the earthquake caused a large number of landslides and landslides geological disasters, road layout along the valley caused serious damage. Based on the detailed information about the earthquake collapse and collapse along the highway in the affected area of about 6 056 km, the paper divides the sections according to the geological structure and seismic intensity, and analyzes the characteristics of each section of the disaster and its relationship with geological structure, seismic intensity and lithology The statistical analysis of each paragraph disaster point density and average size. Put forward Wenchuan earthquake collapse and disintegration zoning, the affected area is divided into extremely strong development zone, strong development zone, more intense development zone, medium development zone and weak development zone 5 areas. Draw the following rules of the landslide disaster in Wenchuan earthquake: (1) The controlling function of the three faults on the development of landslides: the Qianqian fault Dujiangyan-Zhuyuanba section is the area of weak development in the piedmont and the area of medium to strong development Obvious boundary line, the control effect of NE direction of Zhuyuanba is weakened; the central main fault has significant difference between the upper and lower plate disasters from Yingxiu to Donghekou section, and the two extremely strongly developed regions are located in the upper plate, and are dominated by the hind mountain fracture and the important lithologic boundary The restriction of the NE direction control in Donghekou is weakened; the Maowen fault in the hind mountain fault is a clear boundary between the extremely strongly developed region and the more developed region; the Qingchuan-Pingwu fault in the hind mountain fault shows obvious in the Qingchuan- The fault plate effect. (2) Lithologic control effect: There is significant difference in the development degree of earthquake collapse and disasters in different lithology types, intrusion of rock mass and limestone. The dolomite earthquake has the highest density of geological disasters and the largest average scale, and the development density of phyllite disasters The lowest, the smallest, clastic rocks and sand slate between. (3) The role of landform control: the greater the relative elevation of the river bank slope, the steeper the ground slope, the more the earthquake collapse and disasters develop. The hard rock section of the steep slope is the high incidence area of the earthquake collapse hazard. The instability mainly occurs in the upper part of the slope, near the steep slope point. (4) The statistical analysis of 399 measured geological sections shows that the slope of collapse-induced instability site is generally above 40 °. (5) Under dynamic conditions, the slope structure is the controlling factor of the deformation and failure of slope rock and soil mass. The slope of soil layer and strong weathered layer-bedrock slope and developing camber slope are more prone to instability.