RESEARCH ON THE SHRINKAGE AND CRACKING CHARACTERISTICS OF COMPACTED RED CLAY IN HOHHOT

In engineering applications, red clay is prone to shrinkage, deformation and even cracking with the change of ambient temperature and humidity, which leads to many engineering problems. It is undoubted that only by mastering the shrinkage and cracking properties of red clay can effective preventive measures be taken in time. For this reason, this paper takes the typical red clay in Inner Mongolia as the research object. On the basis of the compaction characteristics, the shrinkage characteristics of red clay under different compaction times are analyzed subsequently. The development pattern of fracture morphology of the compacted red clays is further explained by means of image processing technology. The results show that the maximum dry density of red clay increases linearly with the increase of compaction times, while the optimum moisture content decreases linearly with the increase of compaction times. At the same time, the water loss rate varies exponentially with drying time. In the early stage of drying, the water evaporation of the sample changes linearly. With the continuation of drying time, the water evaporation decreases gradually, and the water loss rate curve tends to be stable. Furthermore, with the increase of compaction times, the radial, axial and volume shrinkage changes exponentially with drying time. The shrinkage geometric factor of the red clay is less than 3, which indicates that axial shrinkage is larger than that of radial shrinkage. The shrinkage of the red clay is anisotropic. Increase in the sample compaction times can destroy the clay particles. The average crack width, total crack length and crack percentage of the red clay are increased as well. Simultaneously, the maximum adsorptive capacity of the clay to bound water is weakened. The water holding capacity is reduced, the water loss rate, shrinkage rate and crack percentage increase correspondingly. Therefore, it is inefficient and uneconomical to increase the number of compaction times in engineering application to improve the shrinkage and crack resistance of red clay.