岩溶区桥梁桩基勘察与设计要点分析

Analysis of Key Points in Survey and Design of Bridge Pile Foundation in Karst Area

研究目的:昆明市老320国道升级改造工程地处云贵高原中部,工程地质属侵溶蚀盆地,岩溶发育强烈,岩溶地质的复杂性给桥梁桩基设计带来一定的困难。结合该工程某立交桥桩基设计实践,介绍岩溶形成的机理和特性,探讨岩溶地质桥梁桩基工程地质勘察和设计研究中存在的一些难点问题,总结该类工程地质桥梁桩基勘察设计原则与要点,以供相似工程桥梁设计人员参考。研究结论:岩溶地质勘察必须采用物探与钻探相结合,重视勘察方法和地质构造的研究,提供详实准确的勘察报告。设计必须仔细分析桩基受力特性、选取合理的参数计算桩基的承载力,采用可靠的方法评价顶板的稳定性,必要时进行科学实验,以验证计算分析的准确性,保证工程质量。

Research purposes： The upgrading project of the old 320 National Road in Kunming city is located in the middle part of the Yunnan - Guizhou Plateau, Its engineering geology belongs to the dissolution Basin with strong karst development. The karst complexity brings about some difficulties in the design of the bridge pile foundation. Based on the design practice of this project, the introduction is given to the formation mechanism and characteristics of karst, the discussion is made on the difficult points in the survey and design of the bridge pile foundation in karst area and the design principles and the design main points are summarized for providing the reference to the similar works. Research conclusions：The geophysical prospecting should be used for the karst survey along with drilling. The attention should be paid to the study on the geological structure and the survey method and the detailed and accurate survey report should be supplied. The characteristics of the load on the pile should be considered carefully in design. The reasonable parameters for the calculation of the pile＇s bearing capacity should be chosen, The reliable method should used to evaluate the stability of the roof and the scientific experiments should be done if necessary to verify the accuracy of the calculation and ensure the engineering quality.