GCL膨润土衬垫膨胀量对渗透性能的影响

Influence of swelling on permeability of geosynthetic clay liner

GCL膨润土衬垫有很好的吸水膨胀性能,作为防渗材料被广泛应用在环境工程和水利工程。在上覆荷载作用下,GCL膨润土衬垫的膨胀量会受到影响。采用膨胀试验和渗透试验研究上覆荷载与膨胀量之间的关系,以及膨胀量对渗透系数的影响。结果表明,随着上覆荷载的增加,GCL膨润土衬垫膨胀量明显减小,荷载超过1000 kPa后几乎不会发生膨胀现象。GCL膨润土衬垫膨胀量大,防渗性能低,膨胀量达到12 mm时渗透系数增大1个数量级。根据拟合得到的膨胀量与上覆荷载、膨胀量与渗透系数的关系式,计算了不同堆载高度下的膨胀量和渗透系数,GCL膨润土衬垫上部铺设0.2 m的砂土,能大大提高安全性。

Geosynthetic clay liner(GCL)has good water-absorbing and swelling properties,and is widely used as an impermeable material in environmental engineering and water conservancy projects.The amount of swelling of the GCL is affected under loads.The relationship between the load and the amount of swelling and the effect of swelling on the permeability coefficient were investigated using expansion and permeability tests.The results show that the swelling of GCL decreases significantly with the increase of load,and almost no swelling occurs after the load exceeds 1000 kPa.The permeability of GCL decreases with large swelling,and the permeability coefficient increases by one order of magnitude when the swelling reaches 12 mm.Based on the expressions of the fitted swelling amount and overlying load,swelling amount and permeability coefficient,the swelling amount and permeability coefficient at different stacking heights were calculated.It was suggested that GCL could be covered with 0.2 m of sand or soil to improved the safety of geosynthetic clay liner.