现浇薄壁管桩复合地基竖向承载特性分析

为了解现浇薄壁管桩复合地基的加固机理,在盐通高速公路试验段进行现浇薄壁管桩单桩复合地基静载试验。试验结果表明:现浇薄壁管桩成桩质量好,承载性能好。建立现浇薄壁管桩复合地基三维模型,通过有限元模拟,与现场静载试验结果对比,表明建立的模型是可行的。基于该模型分析了褥垫层模量、桩间距、桩长、土体模量等因素对现浇薄壁管桩复合地基承载性能的影响。结果表明:褥垫层能较好调节桩土应力分配,使桩土共同工作;较大的桩间距虽能充分发挥桩、土承载力,但桩间距的选择要兼顾承载力与变形要求;桩长的增长有利桩体承载力的发挥。地基土模量大有利于桩侧阻的发挥。

Analysis of bearing performance of composite foundation with cast-in-situ concrete thin-wall pipe piles under vertical loads

In order to know the strengthening mechanism of composite foundation with cast-in-situ concrete thin-wall pipe pile,static load tests were conducted in Yan-Tong Expressway.It was shown that the piles were of good quality and high bearing capacity.A 3D model was established for the composite foundation with cast-in-situ concrete thin-wall pipe piles.It was shown by the results of finite element analysis that the present model was reasonable.Based on the model,the effect of cushion stiffness,pile spacing,pile length and soil modulus on the bearing capacity was analyzed.It was indicated that cushion could well adjust pile-soil stress to make piles and soil work together.While the requirements for the bearing capacity of piles and soil could be well developed with large pile spacing,the bearing capacity and deformation should be met.The increasement of pile length could well exert bearing capacity of piles.The large soil modulus was beneficial to the development of shaft friction.