冻融循环对GCL渗透特性的影响

为探究土工复合膨润土垫(GCL)在长期冻融循环作用下的防渗性能，以6h的冷冻和6h的融化为冻融周期对GCL进行冻融循环试验，研究了经历不同冻融次数后GCL渗透系数和自由膨胀率的变化规律.试验结果表明:4h内GCL可以达到冻胀稳定状态；GCL经历冻融循环作用后，再经历冻结时易产生不均匀冻胀；GCL在经历较少(≤30次)冻融循环次数情况下，渗透系数随冻融循环次数增加而减小，其最终渗透系数的量级在10^-11~10^-10m/s之间；随着冻融循环次数的增加，GCL中膨润土的自由膨胀率先增大后减小，最后趋于稳定.

Effect of Freeze-Thaw Cycles on Hydraulic Permeability of GCL

To analyze the anti-seepage performance of geosynthetic clay liner (GCL) after long-term freeze-thaw cycles， the 6-hour freezing and 6-hour thawing cycle tests on GCL material were carried out. The permeability coefficient and free swelling ratio of GCL after different freeze-thaw cycles were studied. The results show that the frost heave of GCL can reach a stable state within 4h， and when frozen again， differential frost heave can occur in the GCL sample after freeze-thaw cycles. When the number of freeze-thaw cycles is low (≤30times)， the permeability coefficient of GCL decreases with increase of the number of freeze-thaw cycles， and the permeability coefficient is between 10^-11m/s and 10^-10m/s. As the number of freeze-thaw cycles increases， the free swelling ratio of bentonite in GCL increases first， then decreases and finally reaches a steady value.