地下水管泄漏所致砂土渗流破坏试验研究

Seepage Failure Experiment of Sandy Soil Caused by Leakage of Underground Water Pipe

为探讨水管泄漏所致砂土破坏机理,研制了水管泄漏所致砂土渗流破坏模型试验装置,进行相关渗流破坏试验,研究泄漏孔径和泄漏水压力对砂土渗流破坏的影响规律。结果表明:在试验初始阶段,土体随径向渗流力的增大发生"流土"现象;当渗流水力梯度大于砂土破坏临界水力梯度时,在泄漏处上方形成一个上抬的空洞,泄漏孔径越小,产生空洞的临界水压力越大;在渗流力作用下,空洞向上移动至表面,空洞消散后土骨架彻底破坏,在泄漏口上方形成贯通的混合流体,这将直接导致土体承载力下降并产生沉陷。

In this paper,the test device of seepage failure model is invented to investigate the sand failure mechanism and study the influence of leakage diameter and leakage water pressure on the sand seepage failure.The results show that flowing soil phenomenon will occur with the increase of radial seepage force in the initial stage of the test.When the seepage hydraulic gradient is greater than the critical hydraulic gradient,a lifting cavity will occur above the leakage,the smaller the leakage diameter is the larger of critical water pressure to form cavity.Soil skeleton is completely destroyed while the cavity moves upward to the soil surface under the action of seepage force,afterward,transfixion mixed fluid will come into being above the leakage,which would directly lead to the decrease of soil bearing capacity and the bigger ground subsidence.