成贵铁路宜宾至毕节段岩溶勘查与选线

Karst Exploration and Route Selection on Yibin-Bijie Section of Chengdu-Guiyang Railway

成贵铁路宜宾至毕节段走行于四川盆地南缘向云贵高原西北部的过渡地带,带内岩溶与岩溶水受多种因素的控制,其中以岩性、构造、地貌条件为主,气象及水网次之。伴随自然地质环境条件的不同,岩溶发育程度和发育形式也不同,岩溶水的分布与富集状况也随之而变化。研究区地壳经历了两次大的抬升,三次夷平,形成三个古岩溶侵蚀面以及相应的多层溶洞。15个岩溶发育的地层中,二叠系栖霞组、茅口组岩溶最为发育,暗河体系规模最大,三叠系次之。根据三个岩溶水文地质单元的特征,线路分别采取绕避、跨越、绕跨结合的方式避让了大型暗河体系,可为复杂岩溶山区铁路、公路地质选线提供指导。

Yibin-Bijie section of Chengdu - Guiyang Railway lies in the transitional zone from the southern margin of the Sichuan Basin to the northwestern of Yunnan-Guizhou Plateau. In the transitional zone, karst and karst water are generally controlled by a variety of factors, including lithology,structure, geomorphology, meteorology and water network. With the variation of natural geological conditions, the development degree of karst, the development pattern of karst , karst water distributions and enrichment degree of the karst water change accordingly. The crust in the study area has experienced two big uplifts and three deplanations, three ancient karst erosion surfaces and the relevant multilayer karst caves are formed. Qixia Formation and Maokou Formation of Permian are the most developed karst in fifteen karst horizons, and the underground river systems are in the largest scale, then followed by the Triassic. According to the characteristics of the three karst hydrogeological units, the railway is circumvented, crossed, and crossed together to avoid the large-scale river systems. The results of this study may provide guidance for geology selection of railway and highway in complicated karst mountainous areas.