Biopolymer efficiently improves the anti-seepage function of compacted clay layer, but research concerning the permeability stability of biopolymer-modified clay during cyclic wetting and drying is scarce. In this paper, the macro-micro structure and the permeability coefficient of biopolymer-modified clay and conventional bentonite-modified clay under the dry-wet cycles are comparatively studied. The bentonite modifier has been found to increase the macro-microscopic cracks under dry-wet cycles, while the xanthan modifier decreases the macro-microscopic fracture rate of the clay. The physical properties of 2% by dry weight of xanthan-modified clay are similar to that of 10% by dry weight of bentonite-modified clay, but the permeability coefficient of the former is lower by approximately one order of magnitude. After the dry-wet cycles, xanthan-modified clay performs better in leakage prevention than bentonite-modified clay. For low-liquid-limit clay, the recommended mass percentage of xanthan gum is 1.5% considering the seepage resistance safety during dry-wet cycles.

中文翻译：

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干湿循环下生物聚合物改性粘土的干缩开裂及渗透性

生物聚合物有效提高了压实粘土层的防渗功能，但有关生物聚合物改性粘土在干湿循环过程中渗透稳定性的研究还很少。本文对生物聚合物改性粘土与常规膨润土改性粘土在干湿循环下的宏观微观结构和渗透系数进行了对比研究。研究发现膨润土改性剂会增加干湿循环下的宏观微观裂纹，而黄原胶改性剂会降低粘土的宏观微观断裂率。2％干重的黄原胶改性粘土的物理性质与10％干重的膨润土改性粘土的物理性质相似，但前者的渗透系数低约一个数量级。经过干湿循环后，黄原胶改性粘土的防渗漏性能优于膨润土改性粘土。对于低液限粘土，考虑干湿循环过程中的防渗安全性，推荐黄原胶质量百分比为1.5%。