考虑桩土差异沉降影响的桩网复合地基桩土应力比分析方法

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。

An analytical method of pile-soil stress ratio for pile-net composite foundation in consideration with the influence of pile-soil differential settlement

The pile-soil stress ratio is an important control parameter for pile-net composite foundation design, which is affected by soil arching effect, membrane effect and pile soil interaction as well as their coupling action, therefore, a concentric arch model is firstly introduced to establish a new analysis model for soil arch effect of pile-net composite foundation considering the relationship between pile-soil differential settlement and the mobilized degree of soil arch effect, and the deformed surface of horizontal reinforcements is regarded as the combination of sphere and cylinder according to its deformation characteristics, a membrane effect analysis model which reflects the influence of pile-soil differential settlement is developed. Secondly, considering the pile-soil interaction and their differential settlement, a load-transfer analysis model of pile-net composite foundation is developed with consideration of the coupling effect among fillings, net and pile-soil reinforcement area, and then a new analysis method of pile-soil stress ratio is put forward. This method can reflect not only the influence of soil arching effect, membrane effect and pile soil interaction on pile-soil stress ratio but also the influence of pile-soil differential settlement on mobilized degree of soil arching effect and membrane effect as well as pile soil interaction. Finally, the feasibility and rationality of the analysis method in this paper are verified through calculation of practical engineering examples and comparison with other existing similar methods.