【摘要】 桩土应力比是反映桩体和桩间土协同工作的重要指标,也是复合地基承载力和沉降计算的重要参数,与地基土的物理力学性质密切相关,影响因素复杂。结合某大型工程,首次对埕岛软土上粉喷桩复合地基进行大型应力比试验,得到埕岛粉喷桩复合地基应力比随荷载、时间、褥垫层厚度、褥垫层刚度的变化规律,并进行有限元分析,对两种结果进行对比。结果表明:粉喷桩复合地基桩土应力比值没有时间效应;粉喷桩复合地基桩土应力比与褥垫层厚度负相关,一定厚度褥垫层可协调桩土工作,宜试验确定最佳厚度范围;应力比与褥垫层弹性模量正相关,模量达到某一值时桩土应力比不再变化,应根据桩体材料选用适当弹性模量褥垫材料;该地区粉喷桩复合地基桩土应力比主要分布在6.5～9.0。更多还原

【Abstract】 Pile-soil stress ratio is a very important indicator to reflect the level of the together-work of the pile and soil,also a major parameter calculating bearing capacity of composite foundation and settlement,and it is interrelated with the physical and mechanical properties of the soil,whose influencing factor is also complicated.Combined with a large-scale project,the large stress ratio test to the DJM pile composite foundation in the soft clay of Chengdao was conducted.The regulations of the pile-soil stress ratio of DJM pile composite foundation with the change of load,time,thickness and stiffness of pillow in Chengdao region were obtained.The finite element analysis was carried out,and these two results were compared.The results show that there is no time effect to the pile-soil stress ratio of DJM pile composite foundation.The pile-soil stress ratio of DJM pile composite foundation is negative correlation to the thickness of pillow.The pillow with a certain thickness could coordinate the work of the pile-soil,and the best thickness range should be confirmed by experiments.The pile-soil stress ratio of DJM pile composite foundation is positive correlation to the elastic modulus of pillow.Pile-soil stress ratio would never change when the elastic modulus reaches a certain value.The pillow material with proper elastic modulus should be chosen based on the pile material.The numerical value of the pile-soil stress ratio of DJM pile composite foundation in this region mainly distributed from 6.5 to 9.0.更多还原