含排水砂垫层地基平面应变固结试验

Experiment of plane-strain ground consolidation with drainage sand cushion

针对含水平排水砂垫层地基的平面应变固结问题,自主研制了一套平面应变固结试验装置,开展饱和重塑黏土上覆不同长度和渗透系数的砂垫层条件下的固结试验,自动量测固结过程中土体超静孔隙水压力和表面沉降量的变化,分析砂垫层长度和渗透系数对土体固结速率的影响。结果表明:固结速率并不仅仅取决于砂垫层的渗透系数,砂垫层的长度也是影响地基固结速率的重要设计参数。砂垫层越长,则地基固结速率越慢,固结完成所需要的时间越长,其原因在于,砂垫层的长度决定了土堤等工程平面应变固结中水平向渗流路径的长短。

A plane-strain consolidation test apparatus was developed to investigate the plane-strain consolidation problem of ground with horizontal drainage sand cushion.Consolidation tests were carried out on saturated remoulded clay overlaid by sand cushions with different lengths and hydraulic conductivities.Variations of excess pore-water pressure and surface settlement of soil were automatically measured during the process of consolidation.The effects of the length and hydraulic conductivity of sand cushion on consolidation were analyzed.Results showed that the rate of consolidation was not only dependent on the hydraulic conductivity of sand cushion.The length of sand cushion was also an important design parameter influencing the rate of consolidation of soil.The longer the sand cushion was the slower the rate of ground consolidation was and the longer the time was required to complete the consolidation.The reason is that the length of sand cushion controls the horizontal seepage path in the plane-strain consolidation in projects such as embankment engineering.