基于贡献率权重模型的川藏铁路沿线大型滑坡危险性区划

川藏交通廊道雅安到林芝段位于青藏高原东南部，沿线地质条件复杂、河流切割强烈、地质环境脆弱、新构造运动活跃，具有山高谷深、坡体稳定性差等特点，是我国崩滑灾害最发育、危害最严重的地区之一。为了保障廊道内相关工程的顺利建设和后期安全运营，本文以线路两侧一级分水岭为界，通过遥感解译和野外调查，获得川藏交通廊道雅安—林芝段崩滑灾害共4509处，在此基础上，选取高程、坡度、坡向、工程地质岩组、断裂、水系、公路、地震动峰值加速度、降雨共9个因子分析了灾害的空间分布规律及发育特征，建立了频率比法与逻辑回归方法耦合模型，并运用到高原山区重大交通廊道崩滑灾害危险性评价中。研究结果表明：(1)廊道沿线各县区段的崩滑灾害面密度在空间上总体呈从西向东递减的趋势。(2)有利于灾害发生的条件分别是：高程1~4 km，坡度大于20°，S、SW和W坡向，较软弱、较坚硬和坚硬岩组，距断裂6.4 km范围内，距水系3.2 km范围内，距公路800 m范围内，地震动峰值加速度0.20g，年均降雨量大于1100 mm。(3)将研究区危险性等级划分为极低危险(18.64%)、低危险(26.18%)、中等危险(24.75%)、高危险(19.82%)、极高危险(10.61%)5级，其中：极高危险区与高危险区主要分布在断裂附近和坡度较陡的区域。(4)耦合模型的AUC值达到了0.737，优于单一的频率比模型的0.712，表明耦合模型的评价结果具有更高的精度。该研究可为川藏交通廊道雅安到林芝段相关工程的规划、建设和未来运营过程中的防灾减灾工作提供重要参考。

Hazard zonation of large-scale landslides along Sichuan-Tibet Railway based on contributing weights model

The Ya'an to Nyingchi section of the Sichuan-Tibet traffic corridor is located in the southeast of the Qinghai-Tibet Plateau. The project region is characterized by complex geological conditions,strong river cutting,fragile geological environment,active neotectonic movement,high mountains,deep valleys and poor slope stability. It is one of the areas with the most developed and serious hazards of collapses and landslides in China. In order to guarantee the smooth construction and safe operation of the related project in the corridor,this study takes the first order watershed on both sides of the line as the boundary,and obtains a total of 4509 collapses and landslides in the Ya'an-Nyingchi section of the Sichuan-Tibet traffic corridor through remote sensing interpretation and field investigation. On this basis,a total of nine factors,including elevation,slope,aspect,engineering geological strata,fault,river,road,peak ground acceleration and rainfall are selected to analyze the spatial distribution law and development characteristics of disasters. Then it establishes a coupling model of frequency ratio method and logistic regression method to evaluate the hazard of collapses and landslides for the major traffic corridor project in plateau mountainous area. The study results show that: (1)The areal density of collapses and landslides in various counties along the corridor shows a spatial decreasing trend from west to east. (2)The conditions conducive to disasters occurrence include elevation of 1~4 km,slope gradient steeper than 20°,aspects of S,SW and W,rock groups of soft,hard and very hard,within 6.4 km of fault,within 3.2 km of river,within 800 m of road,peak ground acceleration of 0.20g and average annual rainfall more than 1100 mm. (3)The hazard of study area is divided into five grades: very low hazard(18.64%),low hazard(26.18%),medium hazard(24.75%),high hazard(19.82%),and very high hazard(10.61%),where the very high hazard and high hazard areas are mainly distributed near the faults and in the areas with steep slopes. (4)The AUC value of the coupling model reaches 0.737,which is better than that of the single frequency ratio model 0.712,indicating that the evaluation result of the coupling model has higher accuracy. This study can provide an important reference for disaster prevention and mitigation in the planning,construction and future operation of the related project in Sichuan-Tibet traffic corridor.