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桩土应力比是桩网复合地基或路基设计的重要控制参数,受土拱效应、拉膜效应和桩土相互作用及其耦合作用的综合影响,为此,本文首先引入几何同心拱模型,考虑桩土差异沉降与土拱发挥程度的关系,建立了新型桩网复合地基土拱效应分析模型,并根据水平加筋网变形特征将水平加筋网变形曲面视为球面与柱面的组合,建立了反映桩土差异沉降影响的拉膜效应分析模型。然后,考虑桩土相互作用及桩土差异沉降,建立了考虑路基填土、网、桩土加固区耦合作用的桩网复合地基荷载传递分析模型,进而提出了其桩土应力比分析新方法。该方法不仅能反映土拱效应、拉膜效应和桩土相互作用对桩土应力比的影响,而且还能反映桩土差异沉降对三者发挥程度的影响。最后,通过工程实例计算以及与现有同类相关方法的比较分析,表明了本文分析模型与方法的可行性与合理性。
The pile-soil stress ratio is an important control parameter for the design of composite foundation or embankment of pile foundation. Due to the combined effect of soil arching, tension membrane effect and pile-soil interaction and its coupling effect, this paper first introduces geometric concentric arches model The relationship between the differential settlement of pile and soil and the degree of soil arching is established. A new soil arching analysis model of pile-soil composite foundation is established. According to the deformation characteristics of horizontal reinforcement mesh, the deformation surface of horizontal reinforcement mesh is regarded as the combination of spherical surface and cylinder surface. The pull-film effect analysis model reflects the effect of differential settlement of pile-soil. Then, considering the interaction between pile and soil and the differential settlement of pile-soil, a load transfer analysis model of pile-soil composite foundation considering the coupling effect of roadbed fill, net and pile-soil reinforced zone is established, and then a new method of pile-soil stress ratio analysis is proposed. The method can not only reflect the effect of soil arching effect, tension membrane effect and pile-soil interaction on the stress ratio of pile-soil, but also reflect the influence of differential settlement of pile-soil on the degree of their exertion. Finally, through the engineering example calculation and comparison with the existing similar methods, this paper shows the feasibility and rationality of the model and method.