Study On Karst Development Law Of Sangzhi Synclinorium Of Qian Zhang Chang Railway

Qian Zhang Chang railway line starts from Qianjiang, via sangzhi County,reachs Zhangjiajie and then Changde.The Sangzhi synclinorium located in Sangzhi County, Zhangjiajie, China’s Hunan Province, belonging to the karst region of southern China. we first collected the regional geological data and drilling, observation points, remote sensing interpretation and other survey data to study the regional geological environment and tectonic features.Considering the modern karst theoretical system is not perfect and the concept of the strength of karst development is also not clearly defined academicly, this paper, referencing to Wang Jiajun, Chun-Guang Zhou and Xiong Tao Kun’s partition classification method of karst development strength in vertical section and the classification method of karst development strength level and it’s indexes,by the Ministry of Railways survey and Design Institute, based on the actual needs of the horizontal partition of karst development strength, using the analogy method to select the individual indicators of karst-development-strength evaluation and to grade those individual indicators, established a karst development strength partition system. Finally we selected three quantitative indicators of the rate of drilling, karst caves scale and density of karst funnel and three qualitative indicators of the rock group features, characteristics of geological formations and karst morphological features as karst-development-strength evaluation indicators, and then the in view of the continuity and similarity of adjacent stratigraphics, this paper, instead of taking stratigraphics as units, divided the study area into four regional units:the northwest wing of LiangShuikou syncline, the southeast wing of LiangShuikou syncline, the northwest wing of Sangzhi-GuanDiping syncline and the southeast wing of Sangzhi-GuanDiping syncline, and used two fuzzy comprehensive evaluation method to evaluate those karst development stength of those units.Finally, according to the analytical results of the tectonic characteristics and two fuzzy comprehensive evaluation to summarize and analysis the discipline of the karst development in Sangzhi-GuanDiping syncline, this paper summarized that:Sangzhi Synclinorium karst development is heterogeneous, karst development is systemic, karst development is directional, Karst development depth is less than the rivers excretion datum, Synclinorium structure and topography have a great impact on karst development, The different single indicators of the same karst development strength grade are different from each other in strength grade.