大瑞铁路怒江四线大跨车站特大桥综合勘察技术与成果分析

大(理)瑞(丽)铁路怒江特大桥为主跨490 m的上承式钢桁拱,具有工程技术难度大和风险高等特点;桥址位于地形地质条件极为复杂的怒江峡谷,高地震烈度、岸坡稳定性、大(巨)型不良地质体、构造压碎岩等重大工程地质问题突出,对桥梁选址与工程设计有重大控制作用。根据怒江特大桥所处地质环境,结合桥梁基础结构和受力特点,有针对性地采用遥感、地质调绘、钻探、工程物探、孔内旁压试验、室内试验等综合地质勘察方法,并开展必要的专项地质工作,查明桥址区地层岩性、地质构造、不良地质、岸坡稳定性等工程地质条件,为桥梁的选址、桥式桥跨方案及基础选型等提供翔实、可靠的地质资料;勘察方法得当、有效,勘察成果准确、可靠。

Comprehensive Survey Technology and Result Analysis of the Four-line Long-span Nu River Station Bridge in Dali-Ruili Railway

The four-line long-span Nu river station bridge with 490 m main span deck steel truss arch is characterized by difficult engineering techniques and high risks. The bridge is located in Nu River Valley with complex topographic and geological conditions,and the major engineering geological challenges,such as high seismic intensity,slope stability,large scale geological body and tectonic rock,play important roles in bridge site selection and engineering design. Based on the geological environment,bridge foundation and the mechanical behavior of Nu river railway bridge, comprehensive survey methods,such as remote sensing,geological survey,drilling,engineering geophysics,pore pressure test and laboratory tests,are employed. Necessary special geological works are carried out to identify such engineering geological conditions as stratigraphic-lithology,tectonic formation,unfavorable geology,slope stability,and provide informative and reliable geological data,such as bridge location,bridge span scheme and foundation type selection. The comprehensive survey methods are proved suitable and effective,and the survey results accurate and reliable.