【摘要】 以舟曲立节滑坡-泥石流灾害链为例,在快速探测滑坡变形特征与内部结构的基础上,分析立节滑坡-泥石流的成灾模式,基于数值模拟开展不同情景下灾害链的危险性定量预测,建立“光学遥感回溯分析-地球物理快速探测-数值模型定量评价”的滑坡-泥石流灾害链危险性综合评价方法,可为青藏高原及周边地区类似灾害链风险预测与应急处置提供参考.立节滑坡是受断裂带控制的黄土-碎石土堆积层滑坡,滑坡崩解滑塌区松散滑坡体和堆积区坡面、沟道堆积物是北山沟泥石流的主要物源,被地表径流侵蚀夹带转化为泥石流,形成滑坡-泥石流灾害链,对沟口立节镇造成严重威胁.为评价可能发生的滑坡-泥石流灾害链效应,利用MassFlow与BASEMENT综合数值建模方法,对滑坡的堆积以及不同降雨情景下可能形成的泥石流的流量、流速、堆积情况进行评价预测,结果显示,假设滑坡强度降低后,有约3.52×105m3滑坡物质极易转化为泥石流,在极端降雨条件下会出现泥石流堵江灾害.更多还原

【Abstract】 With the Lijie landslide-debris flow as a case study, the transformation mechanism was analyzed by detecting the landslide body’s deformation characteristics and internal structure, and a multi-hazards prediction carried out through a numerical simulations approach. The integrated method proposed in this paper, i.e. a backtracking analysis of the optical imagery-rapid detection via geophysical prospectingquantitative prediction through a numerical simulation, can provide a reference for risk prediction and emergency response to similar disaster chains in the Qinghai-Tibet Plateau and other regions. The Lijie landslide with loess and gravel soil is controlled by faults. The loose material of landslide body, channel deposition and slop deposition can be discriminated as the supply source for debris flows in Beishan Gully. Those materials are entrained by the surface runoff and transformed into a debris flow, forming a landslide-debris flow disaster chain and posing a serious threat to Lijie Town at the mouth of the gully.To evaluate the disaster chain effect of the landslide-debris flow, an integrated numerical modeling method including MassFlow and BASEMENT was used to predict the landslide runout under the residual strength, debris flows velocity, discharge and deposits of various recurrence intervals. The results showed that there were about 3.52×105m3of landslide material which can be easily converted into a debris flow when the material strength is reduced, and the debris flow will block the river under extreme rainfall conditions. This prediction result supported the rescue and relief work regarding the disasters chain.更多还原