排水板周围土体径向固结室内模型试验研究
Experimental study on radial consolidation of soil around drainage plate
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摘要: 考虑真空负压沿排水板的衰减分布对排水板周围土体固结特性的影响,开展室内模型试验模拟某一深度处预压地基排水体中真空负压对其周围土体径向固结的过程。通过分析排水板周边土体基本物理力学性质、渗透性、压缩性及土颗分的时空分布特点,研究不同真空负压强度对排水板周围土体径向固结的影响。试验结果表明随着真空度沿着排水体的衰减,排水板对周围土体的影响范围逐渐缩小,在软基深部有大面积的交叉影响区,对软基浅部优于深部;细微颗粒在真空负压差作用下发生向着排水板方向运移并,使得在排水板周围细颗粒含量增大,远端细微颗粒减少;基于真空渗流场理论,结合颗分试验结果,分析了真空预压过程中细颗粒运移成因,进一步解释了“土桩”形成机理。Abstract: Considering the influence of attenuation distribution pattern of negative pressure along a PVD, model tests are carried out to simulate the process of radial consolidation of soil around the PVD at a depth of foundation with vacuum negative pressure. By analyzing the characteristics of the physico-mechanical properties of soil, permeability, compressibility and particle distribution along the radius, the influence of different vacuum negative pressure on the radial consolidation of soil around the PVD is studied. The experimental results show that with the decrease of the vacuum degree along the PVD, the influence of drainage plate on the surrounding soil is gradually reduced and the depth of the soft foundation is better than that of the deeper part. Under the vacuum negative pressure difference, the fine particles move toward to the PVD, making fine particles content increase around the PVD. Based on the vacuum seepage field theory, combined with the test results, the cause of migration of fine particles in the vacuum preloading process is analyzed, and the formation mechanism of the soil pile is further explained.