含碎石粘性土边坡渗流系统的物理模拟试验

在含碎石粘性土边坡中常常发育地下水管道排泄系统,为了掌握它的形成规律和特征,进行了管道排泄系统的物理模拟试验。结果表明,在管道排泄系统的形成过程中,土体渗透性有一个先减小、后增大,最后趋于稳定的过程;土体深度越大形成管道排泄系统所需的时间越长;若土体中粘粒含量高,则形成管道排泄系统所需的时间长,土体的渗透性也相对较低,反之则所需的时间短且渗透性高;当碎砾石含量和粒径较大时有利于管道排泄系统的形成;管道排泄系统的存在使边坡具有良好的渗透性,能有效减小坡体中的渗透力和潜在滑面的孔隙水压力;当管道排泄系统遭到破坏时,边坡的地下水位将明显提高,从而使边坡的稳定性降低。因此,管道排泄系统的存在对保持含碎石粘性土边坡的稳定是十分重要的。

Physical model simulation tests on seepage system in debris-containing clay slopes

Groundwater pipe drainage systems(GPDS)are often found in debris-containing clay slopes(DCS).Physical model simulation tests on seepage system in DCS were made to study the development and seepage behaviors of GPDS.From the test results,several conclusions were drawn as follows:(1)In the process of development of GPDS,the permeability of soil mass of DCS would decrease at the first stage,increase in the following stage,and be invariant at last;(2)In DCS,the deeper the soil mass was,the longer the time needed for the development of GPDS was;(3)The higher the clay particle content in DCS was,the longer the time needed for the development of GPDS was,and the worse the permeability of soil mass was;(4)It was more propitious to the development of GPDS for the soil mass with a higher debris and gravel content,bigger grain diameter;besides,the GPDS developed in this kind of soil mass often had larger permeability;(5)When GPDS developed in DCS,the permeability of soil mass would become dramatically larger,and the seepage force of groundwater and pore water pressure on sliding surface would reduce;(6)As GPDS in DCS was destroyed by external forces,such as construction loads,the groundwater level would rise obviously and this might induce the slope failure.Therefore,GPDS is a very important favorable factor for slope stability.