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针对高含盐环境中普通膨润土防水毯(GCL)抗渗性能严重衰减问题,选取羧甲基纤维素钠(CMC-Na)作为添加剂与膨润土混合,通过试验测定混合物的膨胀指数,再据此制成抗盐型GCL(改性膨润土),并测定其在不同浓度、阳离子盐溶液、长期海水浸泡条件下的渗透系数变化情况。结果表明,常规膨润土在高含盐溶液及海水干湿循环作用下膨胀指数较低,但添加CMC-Na后膨胀指数明显提高;添加CMC-Na制成的抗盐型GCL的渗透系数随着水化液浓度及阳离子价位数升高而增大,但明显低于普通GCL;海水长期浸泡环境下抗盐型GCL渗透系数变化较小,低于普通GCL,且与其膨润土膨胀指数有较好相关性。据此可利用掺加CMC-Na以有效改善高含盐环境下的防渗效果。
Aiming at the problem of serious deterioration of impermeability of common bentonite waterproof blanket (GCL) in high salinity environment, CMC-Na was selected as an additive to be mixed with bentonite so as to determine the swelling index of the mixture by the test Into the salt-resistant GCL (modified bentonite), and measured the change of the permeability coefficient under the condition of different concentrations, cationic salt solution and long-term seawater immersion. The results showed that the swelling index of conventional bentonite was lower under the high salt solution and the wet-dry cycle of seawater, but the swelling index increased obviously after adding CMC-Na. The permeability coefficient of salt- Liquid concentration and cation price increased, but significantly lower than that of normal GCL. Under long-term seawater immersion, the permeability coefficient of salt-resistant GCL changed little, lower than normal GCL, and had a good correlation with the swelling index of bentonite . According to this, CMC-Na can be used to effectively improve the anti-seepage effect under high salt environment.