气泡轻质土在既有路基填筑的变形研究

Study on Filling Deformation of Existing Subgrade with Foamed Concrete

针对气泡轻质土填土路基的变形和破坏机理问题,基于路基弹塑性的理论和实际工程为背景建立了气泡轻质土填土有限元模型,通过数值模拟气泡轻质土分层填筑,分析了气泡轻质土填土路基在受载作用下的应力变化和沉降规律。结果表明:气泡轻质土路基在受载作用下,新老路基交界区域出现应力集中现象,随着上部荷载增加,集中应力越大,路基内部发生破坏现象。当荷载达到200kPa后,上层轻质土路基内部最先发生塑性变形直至破坏;气泡轻质土路基受载后发生沉降变形,由于老路基沉降基本完成,导致新老路基交界区域相互作用易发生裂缝破坏,路基失稳。

To solve the problem of deformation and failure mechanism of the foamed concrete subgrade,based on the elastic-plastic theory and practical engineering background,a finite element model of foamed concrete subgrade is established.Through numerical simulation of the foamed concrete subgrade stratified filling,the stress variation and settlement law of the foamed concrete subgrade under loading are analyzed.The results show that the foamed concrete subgrade under loading,the junction of new and old subgrade appear stress concentration phenomenon.With the increase of the upper load, the greater the concentrated stress is,the more destructive the roadbed will be.When the load reaches200 kPa,the upper foamed concrete subgrade occurs plastic deformation until the load is destroyed firstly;the settlement and deformation of foamed concrete subgrade is caused by loading.The foundation settlement of the old road is basically completed.The interaction between the new and old roadbed is prone to fracture,caused instability of subgrade.