Moisture-heat Coupling Effect of Expansive Soil Cut Slope Deformation and Relationship between Deformation and Raining Time

Expansive soil cut slopes of deferent gradients were built up in Nanning,Guangxi,the relationship between deformation and the raining time was discussed,and the moisture-heat coupling effect of deformation was analyzed through the field test.The test result during one dry season and two rainy seasons in the monitoring period shows that(1) the correlation between horizontal deformation and raining time is well and only successive raining in certain intensity can induce large deformation;(2) the water content variety is the key factor to the slope deformation and the temperature variety may accelerate the deformation process,the coupling action makes the slope unstable.The relationship expression of deformation and the raining time was established on the basis of slope permeability analysis which is suitable to predict total deformation of the slope and converse deformation rate to warn the sudden change of deformation earlier.At the same time,the monitoring results show that the slope deformation decreases immediately with vegetation protected which illustrates that vegetation is an effective protection method for cut slope.