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桩土应力比是反映刚性桩网复合地基工作特性的重要指标。根据刚性桩网复合地基的荷载传递特点,对其在路堤填土荷载作用下的桩土应力分担比进行研究。根据加筋垫层–桩–桩间土应力和位移连续条件,将加固区视为整体进行研究。结合加筋垫层的应力–应变特点,选用大挠度薄板理论模拟加筋垫层的受力和变形。考虑加筋垫层的真实边界条件,首先假定加筋垫层四角点简支其余位置自由并进行桩土应力比求解。在该假定基础之上,考虑桩土相互作用影响,通过功能原理推导出真实情况下刚性桩网复合地基的桩土应力比计算方法。采用室内足尺试验对计算方法进行验证,并综合分析褥垫层模量、桩间距、土体基床系数和桩径对桩土应力比的影响。结果表明理论计算结果与试验结果较为吻合,可为工程实践提供参考。
Pile-soil stress ratio is an important index to reflect the working characteristics of rigid pile foundation. According to the characteristics of load transfer of composite foundation of rigid pile foundation, the stress-sharing ratio of pile-soil under embankment filling is studied. According to the continuous stress and displacement conditions of the reinforced cushion-pile-piles, the reinforcement zone is considered as a whole. Combined with the stress-strain characteristics of stiffened cushion, the theory of large deflection sheet is adopted to simulate the stress and deformation of stiffened cushion. Considering the real boundary conditions of stiffened cushion, we first assume that the other four corners of stiffened cushion are free and the pile-soil stress ratio is free. On the basis of this assumption, considering the effect of pile-soil interaction, the calculation method of pile-soil stress ratio of rigid pile mesh composite foundation under real conditions is deduced by functional principle. The indoor full scale test is used to verify the calculation method. The effects of cushion modulus, pile spacing, soil bed coefficient and pile diameter on pile-soil stress ratio are analyzed. The results show that the theoretical calculation results are in good agreement with the experimental results, which can provide reference for engineering practice.