分级沉降模式下桩–土荷载分担效应模型试验研究
Experimental Study on Pile-Soil Load Sharing Effect Model under Hierarchical Settlement Mode

桩网复合地基具有良好的协调差异变形的能力，但由于受地基固结沉降特征的影响，其承载特性的发挥与桩–土差异沉降量密切相关。为揭示路基渐进沉降模式下桩网复合地基桩–土荷载分担效应，设计了室内缩尺模型模型，考虑桩–土差异沉降、桩间距等参数变化，通过对比桩网复合地基与普通复合地基，对分级沉降条件下的桩–土荷载分担效应开展了研究。研究表明，在同等桩间距条件下，随着桩–土差异沉降量的增大，桩网复合地基与普通复合地基桩顶荷载均增大，且前者明显高于后者；在同等桩–土差异沉降量下，桩网复合地基荷载分担比例及桩土应力比更高，但随着桩间距的增大，桩土应力比以及桩土荷载分担比逐渐减小。通过分析桩–土应力比与桩间距及桩–土差异沉降的关系，建立了分级沉降条件下桩–土应力比的预测公式，为桩网复合地基设计可提供良好的借鉴意义。
In order to reveal the pile-soil load sharing effect under the progressive settlement mode of subgrade, an indoor scale model was designed. Considering the difference of pile-soil differential settlement and pile spacing, the load sharing effect of pile-soil under the condition of graded settlement was carried out. According to the research results, it is proposed that under the same pile spacing condition, with the increase of pile-soil differential settlement, the pile top load of pile-net composite foundation and common composite foundation increases, and the former is significantly higher than the latter. Under the difference of soil settlement, the load sharing ratio and pile-soil stress ratio of pile-net composite foundation is higher than common composite foundation, but the pile-soil stress ratio and pile-soil load sharing ratio decrease with the increase of pile spacing. By analyzing the relationship between pile-soil stress ratio and pile spacing and pile-soil differential settlement, the prediction formula of pile-soil stress ratio under limit and non-limit conditions is established. The research results can provide a good reference for pile-net composite foundation design.