摘要
青藏高原边缘地带堆积体滑坡的发生与地质构造、强降雨、地震等作用密切相关,其中多数属于大型高位堆积体滑坡。为研究其发生机理与稳定性,以舟曲县江顶崖大型高位堆积体滑坡为研究对象,首先,从滑坡所处的地理位置、地质条件等出发,分析滑坡的概况与成因;其次,基于传统传递系数法划分滑坡计算模型,提出滑坡稳定性分析的变坡法;最后,采用Midas GTS NX软件对江顶崖滑坡自然工况下稳定性进行数值模拟分析,并与传统及改进算法结果进行对比。研究结果表明:(1)研究区的地形坡度、地层岩性条件以及活动断裂、历史强震作用是滑坡发生的内因,外因是连续强降雨作用使岩土体力学强度降低以及暴雨导致滑坡前缘的白龙江水位上涨、流速加快,冲刷坡脚导致前缘失稳,滑坡中后缘发生牵引式滑动;(2)运用传递系数法计算折线形滑坡稳定性时,滑面倾角变化值大于10°会导致结果出现较大误差,应用改进的“等分均匀变坡法”可以减小误差,以江顶崖滑坡为计算实例并结合数值模拟验证该方法的有效性;(3)自然工况下模拟发现,滑体的前缘主要表现为水平滑移,滑体的中后部局部主要表现为垂直下沉,而滑坡前缘则主要表现为隆起,因此,滑坡部分区域出现了较大的位移,存在局部滑动的可能性,但是其他区域位移量较小,滑坡整体处于稳定状态。研究成果可供大型高位堆积体滑坡的稳定性分析参考。
The occurrence of accumulation landslides in the edge of the Qinghai-Tibet Plateau is closely related to the effect of geological structures,heavy rainfall,and earthquakes,many of which are large-scale high-position accumulation landslides.To explore the mechanism and stabi-lity of large-scale high-position accumulation landslides,the Jiangdingya landslide in Zhouqu County was taken as the research object.The general situation and causes of the landslide were first analyzed from its geographical location and geological conditions.Then,the landslide calculation models were divided based on the traditional transfer coefficient method,and the variable slope method for landslide stability analysis was proposed.Finally,Midas GTS NX software was used to simulate and analyze the stability of Jiangdingya landslide under natural conditions,and the results were compared with the results of traditional and improved algorithms.The results show that:(1)Topographic slope,stratigraphic lithology,active faults,and historical strong earthquake in the study area are the internal causes of the landslide.The external causes are the mechanical strength reduction of rock and soil due to continuous heavy rainfall,the rise of Bai-long River water level and acceleration of flow velocity at the front edge of the landslide caused by rainstorm,the instability of the front edge,and the traction sliding at the middle and rear edges of the landslide.(2)When using the transfer coefficient method to calculate the landslide stability,the change of sliding surface inclination greater than 10°will lead to large errors in the result,so the improved variable slope method was proposed,and the numerical simulation were carried out on the Jiangdingya landslide to verify the effectiveness of the method.(3)The simulation results under natural conditions indicate that:the front edge of the landslide mainly shows horizontal slip and uplift,and the middle and rear parts of the landslide mainly show vertical subsidence.Therefore,large displacements occur in
作者
丁保艳
翟向华
张卫雄
杨校辉
白志杰
DING Baoyan;ZHAI Xianghua;ZHANG Weixiong;YANG Xiaohui;BAI Zhijie(Gansu Geological Disaster Prevention Engineering Exploration and Design Institute,Lanzhou 730050,Gansu,China;Third Institute of Geological and Mineral Exploration of Gansu Provincial Bureau of Geology and Mineral Resources,Lanzhou 730050,Gansu,China;School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,Gansu,China)
出处
《地震工程学报》
CSCD
北大核心
2022年第4期786-793,802,共9页
China Earthquake Engineering Journal
基金
甘肃省地矿局科创基金项目(2020CX09)
甘肃省高等学校产业支撑计划项目(2020C-40)。
关键词
堆积体滑坡
稳定性分析
破坏机制
数值模拟
传递系数法
landslide accumulation body
stability analysis
failure mechanism
numerical simulation
transfer coefficient method
