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为了充分考虑路堤、格室体、碎石桩以及桩间土体共同作用对路堤荷载下“土工格室+碎石桩”双向增强复合地基桩土应力比与沉降计算方法的影响,以单桩等效加固范围内的路堤与复合地基为分析对象,引入“土柱模型”与环形大挠度薄板分别考虑路堤土拱效应与土工格室的抗弯拉作用,同时基于分层总和法,结合胡克定律与双曲线模型,综合考虑桩体鼓胀与桩土界面滑移,建立了考虑路堤、格室体及碎石桩复合地基共同作用的三维模型,获得了该类复合地基的桩土应力比及沉降计算方法;并采用室内试验数据与某工程实例对该计算方法进行了验证,同时系统分析了格室体与碎石桩的变形特征。结果表明:土工格室可有效增加碎石桩鼓胀范围与鼓胀量,并使其最大鼓胀位置上移,充分发挥其承载能力,格室垫层可明显加大桩体上刺难度,降低土拱效应;在路堤荷载不变的情况下,碎石桩中性点以下部分的桩土相互作用对格室体刚度变化并不敏感;此外,格室垫层“柔性筏板效应”对荷载调节的贡献大于“拉膜效应”。
In order to fully consider the influence of embankment, cell body, gravel pile and soil between piles on the calculation method of pile-soil stress ratio and settlement of “geocell + gravel pile” bidirectional reinforced composite foundation under embankment load, The embankments and composite foundations within the equivalent reinforcement of single pile are the objects of analysis. By introducing “soil column model” and circular large deflection plate, the effect of embankment soil arching and the anti-bending action of geocell are respectively considered. At the same time, Method, combined with Hooke’s law and hyperbolic model, considering the bulging of piles and the interface between pile and soil, a three-dimensional model considering the interaction of embankment, cell body and gravel pile composite foundation was established. The composite foundation Pile-soil stress ratio and settlement calculation method. The indoor test data and an engineering example are used to verify the calculation method. Meanwhile, the deformation characteristics of the cell body and gravel pile are systematically analyzed. The results show that the geocell can effectively increase the bulging area and the bulging capacity of the stone column, and make its maximum bulging position move upward to give full play to its carrying capacity. The grid cushion can significantly increase the degree of piling on the piles and reduce the soil arching Effect of pile-soil interaction under the neutral point of the gravel piles is not sensitive to the change of the stiffness of the cell body in the condition of the same embankment load. In addition, the grid cushion “flexible raft effect” The contribution of adjustment is greater than “pull film effect”.