太行山大峡谷崩塌发育特征及成因模式研究

STUDY ON THE DEVELOPMENT CHARACTERISTICS AND GENETIC PATTERNS OF COLLAPSES IN THE TAIHANG MOUNTAIN GRAND CANYON,CHINA

太行山大峡谷位于山西省壶关县境内的南太行山区,历经亿万年的沧海桑田形成了以峡谷群、峰林石柱、河流瀑布、溶洞等为典型景观的大型高山峡谷景观系统,大峡谷现已建设成为“国家地质公园”和“5A”景区。同时,太行山大峡谷因地处我国第二、三阶梯的地表突变带,构造活动强烈,地表侵蚀严重,在山地特殊气候作用下崩塌灾害频发,时常损毁道路桥梁、破坏生活设施,并危及居民和游客安全,制约景区建设发展。本文立足大峡谷景区地质灾害详细调查,查明大峡谷内发育崩塌达318处,以高位小型岩质崩塌为主,主要分布于海拔700~1100 m之间,崩落高度平均120 m左右,最高可达300 m以上;崩塌多发育在断层带附近和软弱岩层处,沿峡谷两侧呈带状分布,以倾倒式和坠落式的破坏方式为主,具有明显的“群发、多发、复发”的特点。基于对大峡谷景区地形地貌、地层岩性、岩体结构、地表营力及人类活动等崩塌孕灾环境的分析,依据发育区位和致灾效应将崩塌划分为陡壁崩落带、梯状崩石链、碎裂崩滑带和水岸崩塌带4种类型;结合崩塌运动轨迹和对承灾体的效应归纳出崩落滚石型、崩链型、碎裂溃散型、落石涌浪型4种典型成灾模式,并分析提出景区安全防控的对策和建议。研究成果可为高山峡谷区的地质灾害防灾减灾、太行山区的景区开发规划和建设及地质环境保护提供借鉴。

Taihang Mountain Grand Canyon is located in Huguan County,Shanxi Province,which is a part of the South Taihang Mountain in China.After hundreds of millions of years,it has formed a large alpine canyon landscape system represented by canyon groups,peak forest stone pillars,river waterfalls,caves and so on,which has now been built into a"5A"Scenic spot and has the title of"National Geopark"in China.Meantime,the Taihang Mountain Grand Canyon is situated at the surface transition zone between the second and third topography ladders in China.Due to strong tectonic activities and serious surface erosion,as well as unique climate changes in this area,a series of collapse disasters occur frequently,damaging roads and facilities,which often endanger the safety of residents and tourists.Through geological disaster investigation,318 collapse disasters have been identified in the grand canyon area,which are dominated by high-level small-scale rock collapses.They are mainly distributed between 700 and 1100 meters above sea level,with an average drop of about 120 meters and a maximum of more than 300 meters.These collapses are mostly developed in areas where faults and weak rock strata are dense,and are distributed in bands along both sides of the canyon,showing the characteristics of cluster,multiple occurrence and recurrence when rainfall is concentrated in this canyon.Based on the analysis of the disaster-pregnant environment for the collapse of the scenic spot,it is found that under the action of the major disaster factors such as topographic landform,stratigraphic lithology,rock mass structure,surface agency and human activities,the collapse disaster-forming patterns consist of steep collapse zone,ladder-shaped collapsed rock chain,catastrophic collapse and sliding zone,and waterfront collapse zone.Finally,this paper summarizes four collapse types including collapse rolling stone type,collapse chain type,fragmentation type and falling rock surge type,and then puts on the related prevention and control suggestions for these disaster types.This study can provide reference and support for geological disaster prevention and mitigation in canyon areas,development and construction of scenic spots in Taihang Mountain,geological environmental protection and community safety.