Experimental Study On Fracture Development Of Guilin Red Clay With Different Clay Content

The main components of Guilin red clay are kaolinite,montmorillonite and illite,which have high natural water content,high porosity ratio and high liquid plastic limit.In the process of evaporation and water loss,it is easy to shrink and produce cracks,destroy the structure of soil and affect the strength of soil.In the past studies,there are many studies on the effect of initial moisture content and dry-wetting cycle on fracture development,but there are few studies on the effect of clay content on fracture development.In this paper,taking Guilin red clay as the research object,the law of fracture development of Guilin red clay with different clay content was deeply studied,and the characteristics of fracture development were quantitatively analyzed.The main research contents are as follows:1.Red clay with different clay content was prepared by extracting clay particles from red clay using the principle of water purification sedimentation.The process of red clay fissure development was weighed and photographed by self-made weighing and photographing equipment,and the water loss process of red clay with different clay content was recorded.The results show that the water loss process and the final water loss rate of the sample are affected significantly by temperature.The change of clay content and initial water content had no obvious effect on the water loss rate of red clay.2.By processing the crack image,parameters such as crack area and crack length in the process of crack development in red clay were measured.The results show that there are three stages in the development of fracture morphology,the growth of fracture area with time and the development of fracture length in red clay.3.Temperature has obvious influence on the fracture development of Guilin red clay.The crack rate and average crack width of red clay with the same clay content increased with the increase of temperature.There is no obvious rule between the crack length of red clay and the ambient temperature and clay content of evaporation water loss.When the initial water content is the same,the water loss rate and surface shrinkage rate of the crack area and length of red clay with different clay content increase with the increase of water loss temperature.4.The relationship between fissure development and initial water content of Guilin red clay is great.When the temperature is 20 ℃,the crack area of the red clay increases continuously with the increase of the initial water content from the optimal water content to the natural water content,and the difference between the crack rate of the red clay with the initial water content of the liquid limit and the crack rate of the initial water content of the natural water content decreases with the increase of the clay content.The surface shrinkage increases with the increase of initial moisture content.When the temperature is 60 ℃,the crack area of red clay continues to increase with the increase of water content.The surface shrinkage increases first and then decreases with the increase of initial moisture content.At the same temperature,the crack length of red clay with the same clay content increases first and then decreases with the increase of initial water content.The average crack width increases with the increase of initial water content.With the increase of initial water content,the water loss rate of fracture area and length decreases first and then increases.5.The difference of clay content has a great influence on the fracture development characteristics of Guilin red clay.When the temperature and initial water content are the same,the crack rate,crack width and surface shrinkage of red clay decrease with the increase of clay content.With the increase of clay content,the development of crack length in red clay firstly increases and then decreases.The change of clay content has a certain influence on the water loss rate of the development of fracture area and length in red clay,but there is no obvious rule.