澧水特大桥索塔基坑岩溶病害处治方法研究

张家界至花垣高速公路地处湘西北,是湖南省高速公路网规划“五纵七横”路网中—长沙浏阳（赣湘界）至花垣（湘渝界）高速公路的重要组成部分.受水文地质环境的限制,在西部山区修建高速公路时,常常会遇到一些岩溶病害问题.首先,以张花高速公路中的澧水特大悬索桥索塔基础基坑为工程实例,深入探讨了该特大桥索塔基础基坑岩溶病害发育特点,并以此为基础,对基坑侧壁及基底岩溶的稳定性进行了分析评价.其次,根据澧水特大悬索桥索塔基础基坑岩溶实际分布情况,提出了岩溶及溶缝处治基本原则,进而得到了索塔左基坑岩溶病害处理方案.最后,通过承载力试验及补钻孔取芯的方法对处治效果进行了检测,结果表明：处治后的基坑基底地质情况良好,满足设计要求,证明本文岩溶病害处治方案是合理可行的,可以为类似的工程提供有力参考.

Study on the Treatment to the Karst Cave under the Foundation Pit of Cable Tower of the Lishui Extra Large Suspension Bridge

Zhangjiajie to Huayuan expressway is located in northwestern of Hunan province,and it is an important part of road-Liuyang Changsha （Hunan and Jiangxi sector） to Huayuan （Xiang Yu sector） in Hunan province highway network planning ＂five verticals and seven horizontals＂.Because of hydrogeological conditions,the construction of the highway in the western mountains,often meets some problems of karst diseases.First of all,take Lishui extra large suspension bridge cable tower of zhanghua expressway for engineering example,discussing the development characteristics of the cable tower foundation pit of the large bridge in karst disease,and on this basis,analyzes and evaluates the stability of the foundation pit wall and basal lava.Secondly,according to the actual distribution of basal lava of the large suspension bridge cable tower basement,put forward basic treatment principles of karst and dissolved fracture,and come to an treatment scheme of karst disease.Finally,test the treatment effect through the bearing capacity test and the method of core drilling,the results show that：the foundation pit base geological conditions after treatment is good,meet the design requirements,and show that the karst disease treatment scheme is reasonable and feasible in this paper and can provide a powerful reference to similar engineering.