高速公路软土地基拼宽方案及沉降分析研究

为研究桩型、桩间距及填土高度对拼宽路基差异沉降的影响,采用二维比奥固结理论,利用FLAC软件进行数值模拟。模拟结果表明,对于新旧路基差异沉降的控制PTC管桩处理效果优于水泥搅拌桩,桩间距1.2~1.5 m变化对水泥搅拌桩处理效果影响不明显,而桩间距2.0~3.5 m变化对PTC管桩处理效果影响较大。因此,设计首先应合理选择处理方案,在满足沉降控制标准要求的前提下,合理选取桩间距,从而降低工程造价。

Settlement Analysis and Widening Scheme of Soft Soil Foundation of Expressway

In order to determine the foundation treatment method of widening expressway subgrade in soft soil area,the effects of pile type,pile space and filling height on the differential settlement between the new and old subgrade were simulated by the two-dimensional Biot consolidation theory using FLAC software.The results show that the foundation treatment by the PTC pile treatment exhibits lower differential settlement between the new and old subgradethan that by the cement mixing pile treatment.The effects of the pile space varying from 1.2 m to 1.5 m has no obvious influence on the cement mixing pile treatment.However,the space varying from 2.0 m to 3.5 m makes a strong impact on the treatment effect of the PTC pile.According to the simulation results,the first step is to choose the proper foundation treatment method for expressway widening in soft soil area to control differential settlement between the new and old subgrade.On the premise of satisfying the requirement of differential settlements controlling standard,it is very important to choose reasonable pile space and pile length to reduce the cost of the project.