新建红柳至一里坪铁路工程地质特征及选线研究

Study on the Line Selection and Railway Engineering Geology Characteristics of Hongliu- Yiliping Railway

研究目的:新建红柳至一里坪铁路位于敦煌至格尔木铁路红柳站与柴达木盆地腹地一里坪之间,沿途经过盐沼盆地、早期湖积盆地、雅丹地貌三个地质地貌单元,交错分布有风沙、岩溶、地震、崩塌、软土、盐渍土、盐岩及盐渍岩、季节性冻土等地质现象,生态环境脆弱,水文环境、地质环境复杂多变。地质工作需查明控制线路方案的地质因素,综合分析其危害,预测其对工程可能产生的不利影响,为线路选择及工程设置提供依据。研究结论:(1)柴达木湖积盆地以盐为本,以水、风为介质,盐的搬运、沉积在相对封闭的盆地内循环不止;(2)祁连山、昆仑山坡麓一带的盐沼湖,水补给充足,湖内软土、季节性冻土、岩溶发育,难以治理,线路采用了绕避方案;(3)雅丹地区,地表多被"盐被"覆盖,部分沙漠化,采用桥方案短距离通过风沙地带;(4)早期干湖积盆地内地质条件相对较好,线路长段通过;(5)工程建设应以盐治沙,保护"盐被",保持水环境的稳定;(6)本研究可为相似地质特征的选线及工程设计提供一定的参考价值。

Research purposes： The new railway of Hongliu - Yiliping is in between the Hongliu station of Dunhuang - Golmud Railway and Yiliping in the Qaidam Basin, passing cross three geological landform units： salt marsh basin, early lake sedimentary basin and Yadang landform, distributed with the geological phenomenon such as sandstorm, karst, earthquake, collapse, soft clay, saline soil, salt rock, seasonally frozen soil, etc. The ecological environment is weak, the hydrological environment and geological environment are complicated. The geological factors which control the route plan should be clearly investigated, the hazard should be comprehensively analyzed, the adverse effects to the railway should be predicted, the basis for the route choice and project settings should be provided. Research conclusions：（ 1 ） In the Qaidam lake deposited basin, the salt is continuously carried and deposited in this relatively closed basin, wind and water as the medium. （2） The salt lake located in the footslope of the Qilian Mountains and the Kunlun Mountains is amply supplied with water, the soft clay, seasonally frozen soil and karst are widely distributed and difficult to be disposed, the route is chose to pass around. （3） In the region of Yadang landform, the land is covered by the ＂salt bed＂ , some part is desertificated, the bridge -plan is chosen to pass through the sand belt in short distance. （4） In the dry early lake sedimentary basin, the geological conditions are relatively good for the route passing though in long distance. （5） In engineering construction, the sand should be controlled by salt, the ＂salt bed＂should be protected, the water environment should be controlled in stability. （6） The research results provide a certain reference value for line selection and engineering design of the similar geological characteristics.