大直径深孔穿越岩溶旋挖钻孔桩施工技术

Construction technology of large diameter deep hole crossing karst rotary excavation bored piles

针对传统工艺在施工复杂地质下,尤其是溶洞区下的大直径深孔桩时容易出现卡钻、浆液面骤降导致孔壁坍塌、泥浆与河道串通流失等情况,为解决此类地质情况下成孔、桩基成型难题,本文结合郑万高铁湖北段10标神农溪双线大桥主墩桩基施工的实际情况及特点,通过采用三级变截面全钢护筒跟进配合旋挖钻干钻的方式,顺利穿越了多层溶腔群,解决了深孔岩溶地段漏浆、塌孔及水质污染的难题,取得了景区施工良好的环保效益。

In view of the traditional technology in the construction of complex geology, especially large-diameter deep-hole piles under the karst cave area, it is prone to sticking, the sudden drop of the slurry surface leads to the collapse of the hole wall, the collusion of mud and the river channel, etc.In order to solve this kind of geological situation difficulties in hole formation and pile foundation formation, this article combines the actual situation and characteristics of the pile foundation construction of the main pier of the Shennongxi double-line bridge on the 10 th bid of the Zhengwan high-speed railway in Hubei.The drilling method successfully passed through the multi-layer karst cavity group, the problems of slurry leakage, hole collapse and water pollution in the deep-hole karst section are solved, and good environmental protection benefit in the construction of the scenic spot is achieved.