桥头软基现浇筒桩处理现场试验分析

为研究现浇筒桩和土工格栅加筋碎石垫层组成的复合地基加固软弱路基的作用机理及效果,介绍了某高速公路桥头筒桩处理中进行的地表沉降、分层沉降、深层土体位移、孔隙水压力、桩土应力等项目的现场测试成果。结果发现:该处理方法具有经济合理,承载力高,沉降小等特点,为解决软土“桥头跳车”提供了一种经济、有效的手段;土工格栅可以很好地调节荷载分布,使荷载更多的向桩身集中;超静孔压不大,且有规律性,不影响沉降稳定性;地基侧向变形小,变形速率在时间和深度上都呈递减趋势。

Analysis of cast-in-situ tubular piles in soft foundation improvement at bridge approaches

To study the performance and feasibility of tubular piles with geogrid reinforced macadam cushion,field test results,including settlement,lateral movement,pore water pressure,and pile-soil stress,are presented.The study indicates that the piles may improve the bearing capacity and meet engineering requirement on settlement with low cost,providing an economical and effective solution to the difficult problem of"bump at bridge-head"with soft foundations.The geogrid can adjust the load distribution,thus causing the pile to carry more load and the foundation becoming more stable.Since the excess pore pressure is small,it has no influence on the stability of the foundation.Besides,the horizontal ground displacement is also small,thus the deformation rate decreases with time and depth.