海洋环境强震区超大直径桩基钢护筒 下沉问题与处理技术.

The design diameter of the main pier pile foundation is 4 m in Puqian Bridge at Hainan Province, the steel tube diameter 4.3 m, length 25.7 m, used in pile foundation construction, there are few application of such a large diameter steel tube in bored pile at present. Restricted by the rock and soil condition such as gravel, pebble soil and breeze at the bridge site, steel casing often appears to sinking difficulties in the process of sinking. According to the site condition of marine environment and strong earthquake area and the condition of rock and soil in bridge site area, three technical solutions are compared to solve sinking difficulties according to 4.3 m large diameter steel casing in Puqian Bridge, we put forward that reduce the steel tube length, and increase the reinforcement ratio of pile foundation, in order to enhance pile foundation bending and shearing capacity, and to meet the seismic performance of the pile foundation under strong earthquake. [ABSTRACT FROM AUTHOR]

:海南省铺前大桥主桥墩桩基础设计桩径4 m，桩基施工过程中采用的钢护筒直径4.3 m，长度25.7 m，如此 超大直径的深长钢护筒目前在国内外钻孔灌注桩中鲜有应用。受桥址区砂砾、卵石土、微风化花岗岩等岩土地质条 件限制，钢护筒在下沉过程中出现下沉困难的情况时有发生。根据铺前大桥海洋环境及强震区的场地条件、桥址区 岩土地质情况，比较了解决铺前大桥主桥墩准4.3 m超大直径钢护筒下沉困难的3种技术方案，并提出对不能下沉就 位的钢护筒可通过减小钢护筒长度，适当增加桩基础配筋率的措施，以增强桩基础的抗弯、抗剪能力，满足强震作 用下桩基础的抗震性能。 [ABSTRACT FROM AUTHOR]