Correlation Between Disintegration And Penetration Of Red Clay In Guilin Area

Guilin,located in the low latitude area,is the subtropical monsoon climate and with the rainy days throughout the year.Guilin,s rainy and hot days are basically in the same season.Under such wet and rainy natural conditions,the soil strength is can be easily decreased due to the water immersion.The red clay with uneven stress is easy to be soften due to humidifying and disintegration,which leads to the Geological hazards such as slope failure,gully,foundation failure,cave development and landslide occur,which causes unnecessary economic losses.With the extensive use of remolded red clay in backfilling projects,including subgrade works,is increasingly using remolded red clay.In this paper,from the safety and practicability of remolding red clay as backfill for backfilling,the disintegration characteristics of remolded red clay under actual engineering conditions are studied.By starting the red clay in Yanshan area of Guilin as the research object,doing a large number of indoor geotechnical tests and searching the disintegration law and mechanism of soil under different conditions,and combining the correlation between the disintegration and soil permeability test,we get the main conclusions and results as follows:(1)The disintegration of soil sample is not a uniform process,because of the invasion of water molecules,which leads to expansion damage from the surface to the inside.Firstly,water intrudes,cracks penetrate,and then disintegrate and destroy.During the whole process of destruction,the disintegrated soil debris usually falls to the disintegrating cylinder bottom in the form of powder and granular.In the process of disintegration,the surface of soil sample will rise with bubbles,and the surrounding water body will become turbid at the initial stage of disintegration.When the violent disintegration process is over,no more debris like disintegrating soil will fall into the bottom of the disintegrating cylinder through the mesh board,and the water body will be clear again.(2)Considering the percentage of moisture and dry density as the controlling variable of soil disintegration,which can conclude that when the water content is constant,the disintegration amount of soil sample will decrease with the increase of dry density.However,if the dry density is constant,the final disintegration amount of soil sample does not show obvious regularity.When the moisture content is constant,the disintegration of soil sample will gradually decrease with the increase of dry density.(3)Considering different water level heights as influencing factors,it is found that with the increase of time,when the water content and dry density of soil samples are constant,the amount of disintegration increases gradually with the increase of water level depth(overlying water pressure).(4)Considering different water level heights(i.e.overlying water pressure)as the influencing factors,it is found that with the increase of time,when the water content and dry density of soil samples are constant,the amount of disintegration completed increases gradually with the increase of water level depth.(overlying water pressure).(5)The disintegration of cubic soil decreases with the increase of fiber content in the experimental process considering different fiber content as the influencing factor.The disintegration of soil samples with fibers is much weaker than that without fibers.Therefore,the addition of polypropylene fine fiber can significantly improve the disintegration resistance of soil samples.(6)The average rate curve of disintegration of different graded soil samples with different inhomogeneity coefficient was obtained by considering the disintegration experiment process of mixing standard sand to change the gradation of soil samples as the influencing factor.It can be seen that with the increase of non-uniformity coefficient,the disintegration rate of soil sample gradually slows down.(7)Through the permeability test and disintegration test of saturated soil samples,it can be seen that with the increase of dry density,the permeability coefficient of saturated soil samples decreases gradually,and the disintegration rate of the disintegration process decreases gradually at the same time.Permeability coefficient and average disintegration rate are negatively correlated with dry density,and their correlation is very high.(8)The permeability coefficient of saturated soil samples with dry density of 1.25g/cm~3and 1.35g/cm~3was gradually increased with the increase of fiber content in polypropylene fine soil samples,while the disintegration rate of saturated soil samples during disintegration process was gradually decreased.Whether the dry density is 1.25g/cm~3 or 1.35g/cm~3,the permeability coefficient is positively correlated with the fiber content,and negatively correlated with the average disintegration rate.The correlation is very high.