水生植物根系对膨润土防水毯渗透性能影响

Influence of Aquatic Plant Roots on Hydraulic Conductivity of Geosynthetic Clay Liner

膨润土防水毯(geosynthetic clay liner,GCL)是常用于湖底防渗的新型材料,但湖泊水生植物根系的生长可能对GCL的防渗效果产生影响。为探究植物根系穿透下GCL的渗透性能,选取再力花、芦苇、香蒲等植物开展模型试验,并采用全自动渗透仪(global digital systems,GDS)对水生植物根系穿透后GCL的渗透系数进行测量,分析渗透系数随根系穿透率、根系状态和根系种类的变化规律。研究表明:在相同围压条件下,植物根系贯穿下GCL渗透系数随根系穿透率的增加而增大,最大增至10^(-7) m/s;当根系穿透率大于1%时,GCL渗透系数在根系枯萎状态下约为正常状态下的1.26~3.13倍,根系枯萎状态对GCL渗透性影响更显著;香蒲、芦苇根系对GCL渗透性能影响程度相当,再力花根系对GCL渗透性影响较小。

Geosynthetic clay liner(GCL)is a new type of material commonly used for lake bottom seepage prevention,but if the roots of lake aquatic plants penetrate into GCL,it will affects its seepage prevention effect.In order to explore the influence of GCL's hydraulic conductivity under the penetration of plant roots,model tests were carried out on plants such as Thalia dealbata,reed,and cattail,global digital systems(GDS)geoenvironmental permeameter was used to test the hydraulic conductivity of GCL after the penetration of aquatic plant roots.The results show as follows.Under the same confining pressure,with the increases of the penetration rate of plant roots,the GCL hydraulic conductivity under the penetration of Thalia dealbata,reed and cattail roots gradually increase,and the maximum increases to 10^(-7) m/s.When the root penetration rate is greater than 1%,the GCL hydraulic conductivity of withered roots is about 1.26~3.13 times that of the normal roots morphology.The withered roots have a more significant impact on GCL permeability than the normal root morphology.The roots of cattails and reeds have similar effects on the hydraulic conductivity of GCL,while the roots of Thalia dealbata have little effect on the hydraulic conductivity of GCL.