城镇地区溶洞桩基施工塌陷及方案调整案例探析

桥梁桩基础施工受地质条件影响大,岩溶发育地区桩基施工尤为困难,如遇大型溶洞而处理方法不当,往往会造成掉钻或卡锤、漏浆,甚至地面塌陷,危及周边结构物安全并造成人员伤亡,尤其在城镇区域后果将更为严重。以位于城镇区域某高速公路桥梁桩基施工中的一个大型溶洞处治方案为例,介绍原设计桩基溶洞处治方案,分析施工过程中发生坍塌的原因;进而根据地质补勘结果,提出相应的处治方案,并简要介绍后续施工的注意事项;总结出城镇岩溶发育地区溶洞处治的相关注意事项及经验,可为其他同类项目提供参考。

Case study of karst cave collapse during pile foundation construction and scheme adjustment in urban area

The construction of bridge pile foundation is greatly affected by geological conditions, especially in karst cave development area. The improper treatment of large karst cave often causes dropping or sticking of drill bit, mud leakage, even ground collapse, which endanger the safety of surrounding buildings and people, particularly in urban areas. Taking treatment plan of a large karst cave in the pile foundation construction of a highway bridge in an urban area as an example, original design treatment plan of karst cave of the pile foundation was introduced, the reasons of collapse during the construction process were analyzed. Then the corresponding treatment plan was proposed according to the results of geological survey, the attention matters for the subsequent construction were briefly introduced. The relevant attention matters and experience in karst cave development area of urban were summarized, which can provide reference for other similar projects.