In the hydration process of compacted Gaomiaozi (GMZ) bentonite with technological voids, the cracking phenomenon happens simultaneously with self-sealing. In order to investigate the effect of sample thickness, a series of hydration tests were carried out in this paper and the evolutionary process of bentonite was visualized using a custom-designed device. Corresponding digital images were acquired by time-lapse photography and analyzed by image processing techniques. Experimental results showed that the sample thickness exerted an apparent effect on both the self-sealing and the hydration cracking of compacted bentonite. Increasing thickness slowed down the self-sealing process and thus prolonged the time needed to seal the technological voids. Moreover, it was found that thickening the sample inhibited the development of hydration cracks and simplified the crack network notably, indicated by a decreasing trend of crack amount, length and area. In addition, the fractal dimension, characterizing the complexity degree of crack network, decreased with the increase of thickness. By fitting and predicting, a critical value was obtained that if the sample thickness exceeded it, no hydration cracks could be observed on the surface and no penetrating cracks could be formed in the sample. These conclusions are of great importance in the design of bentonite barriers by reducing the incidence of hydration cracks.

在具有工艺空隙的压实高庙子（GMZ）膨润土的水化过程中，开裂现象与自密封同时发生。为了研究样品厚度的影响，本文进行了一系列水化试验，并使用定制设计的装置对膨润土的演化过程进行了可视化。通过延时摄影获得相应的数字图像，并通过图像处理技术进行分析。实验结果表明，试样厚度对压实膨润土的自密封和水化开裂均有明显影响。增加厚度会减慢自密封过程，从而延长密封技术空隙所需的时间。而且，研究发现，加厚试样抑制了水化裂纹的发展，显着简化了裂纹网络，表现为裂纹数量、长度和面积的减小趋势。此外，表征裂纹网络复杂程度的分形维数随着厚度的增加而减小。通过拟合和预测，得到了一个临界值，即如果样品厚度超过该临界值，则样品表面不会出现水化裂纹，也不会在样品中形成穿透性裂纹。这些结论对于通过减少水化裂缝的发生率来设计膨润土屏障具有重要意义。随着厚度的增加而减小。通过拟合和预测，得到了一个临界值，即如果样品厚度超过该临界值，则样品表面不会出现水化裂纹，也不会在样品中形成穿透性裂纹。这些结论对于通过减少水化裂缝的发生率来设计膨润土屏障具有重要意义。随着厚度的增加而减小。通过拟合和预测，得到了一个临界值，即如果样品厚度超过该临界值，则样品表面不会出现水化裂纹，也不会在样品中形成穿透性裂纹。这些结论对于通过减少水化裂缝的发生率来设计膨润土屏障具有重要意义。