大理至瑞丽铁路大理西车站路基设计

Subgrade Design of Dali West Station on Dali-Ruili Railway

大理西站位于西耳河右岸,属典型的剥蚀中山峡谷地貌。地震烈度高,地形、地质条件极其复杂,路基工程修建难度大是本站路基工程设计最大的特点。在地震烈度高达8度的短短1 km范围的路基工程,受1条区域大断层及2条支断层的影响,不良地质及特殊岩土发育有泥石流、滑坡、岩堆、顺层、危岩落石、人工坑洞、陡坡人工弃土等不良地质体。针对如此复杂的地形、地质条件,路基工程灵活采用环形柔性防护网,锚索(杆)框架梁轻型柔性加固防护技术,土钉墙原位加固技术,锚索桩板墙加锚索框架梁,桩基托梁衡重式挡墙等新型组合式支挡结构,实现了工程结构设计合理的多样化、组合化、新型化、轻型化、柔性化的工程设计理念。在技术方案研究中"总体着眼、专业入手"并突出路基工程系统风险控制,合理选择了明洞方案穿过泥石流沟,适当缩短了地震时难以修复的傍山桥工程,做到了工程选择合理化、综合化、系统化。

Dali West Station is located on the right bank of Xi＇er River that belongs to the typical denuded ravine landform. The design of subgrade is strongly featured by high seismic intensity,extremely complicated landform and geology.This subgrade works in the range of only 1 km,where the seismic intensity reaches 8 degree,are impacted by a large regional fault and two branch faults. Unfavorable geology and special geotechnical development include mud-rock flow,landslide,talus,bedding,overhanging rock and rock fall,pothole and steep hill spoil. In view of such complex landform and geology,annular protecting net,lightweight and flexible reinforcement and protection technology of anchor（ rockbolt）,in-situ reinforcement technology of soil nailing wall,slab-pile wall with anchor and frame beam with anchor,weight balanced retaining wall on the supported beam of pile foundation and other new combined retaining structures are adopted for subgrade works to realize the engineering design ideas of diversity,combination,new type orientation,lightweight trend and flexibility. In the study of the technical proposals,we focus on the overall things and start with the specialties. Besides,systematic risk control of subgrade construction is highlighted,and open-cut tunnel is reasonably chosen for passing mud-rock flow gully,which greatly reduces the renovation construction of bridges by the side of mountains. Rationalization,integration and systematization of engineering choice are achieved.