中老铁路桥梁桩基岩溶处理的施工技术

Construction Technology of Karst Treatment for Pile Foundation of China-Laos Railway Bridge

依托中老铁路朋松楠松河特大桥岩溶桩基施工,综合工程安全、质量、工期、成本、环境等多方面因素,研究不同发育形态岩溶较适用的处理技术,对比分析抛填黏土片石筑壁法、钢护筒跟进法及两者相结合的处理方法在不同发育形态岩溶处理中的优缺点和适用性,结果表明:对于小型空洞、中型全填充或局部填充溶洞,抛填黏土片石筑壁法可快速、高效、经济地完成溶洞处理;对于中型空洞、大型溶洞、形成较大地下水流通道的溶洞,抛填黏土片石筑壁法与钢护筒跟进法相结合的处理方法有效解决了单个处理措施施工中伴随的工效低、易塌孔、灌注混凝土超方、钢护筒挤压变形等问题,经济、高效地完成了该溶洞处理。根据本研究成果,提出了桥梁桩基岩溶处理较适用的选定原则及控制要点。

On the base of the karst pile foundation construction of Houay Xong Great Bridge in China-Laos Railway, the comprehensive construction safety, quality, construction period, cost, environment and other factors are studied, and the suitable treatment technologies for different developed karst forms are studied. Compare the advantage, disadvantage and applicability with the method of cast-in-place clay rubble wall building and method of steel casing follow-up and the combination of both methods in different developed karst forms, the results show that: for small-sized cave, medium-sized full filled or partially filled karst cave, the method of cast-in-place clay rubble wall building can complete the karst cave treatment quickly, efficiently and economically;for medium-sized cave, large-scale karst cave and karst cave that forms large underground water flow passage, the method of cast-in-place clay rubble wall building combined with the method of steel casing follow-up can effectively solve the problems in single treatment measures such as low work efficiency, easy hole collapse, over casting of concrete, and extrusion deformation of steel casing, so that to complete the cave treatment economically and efficiently. According to the results of this study, the selection principles and key control points of karst treatment of bridge pile foundation are put forward.