Effect Of Freezing And Thawing Of The Soil Slope Stability The Study

In the process of freezing and thawing, soil structure affected cryogenic effect, resulting in physical and mechanical properties change. When cutting excavation, new cutting slope and other engineering activities in cold regions, it will make the newly exposed soil under freezing and thawing, easily lead to the occurrence of damage to the slope, slope stability and safety of the structure resulting in greater harm.This paper mainly gravel and clay with high liquid limit silt containing Luhuo area for the study, by freeze-thaw cycle test and indoor soil test, the water content of different two different soil dry density at different times freeze-thaw conditions shear strength parameters c cohesion and variation of internal friction angle φ and apply resulting c, variation φ value to the pit slope. Then use finite element software ANSYS pebbly clay slope at different times of freeze-thaw numerical simulation study on stability of freeze-thaw cycles on pebbly clay slope. Slope project area for the cold freezing disaster prediction and prevention to provide more reliable experimental and theoretical basis. Through experiment and numerical simulation analysis, research results are as follows:(1)Through different times of freezing and thawing, pebbly clay 2 mm and above large particles of clay and gravel particle size constant, fine particles of clay 2 mm or less increased, but the magnitude of change is small. Liquid limit decreases, the first increase after plastic limits stabilized plasticity index decreased and the number of freeze-thaw stable over 5 times. With the increase in the number of freeze-thaw, dry density at different moisture content of 16.7%, 21.4% of the sample increases cohesion, internal friction angle decreases; a water content of 19.0% of the sample reduced cohesion within friction angle increases. Samples with different water content at the same cohesion as the number of freeze-thaw dry density decreases, the internal friction angle is increased. Dry density of different samples at the same number of freeze-thaw cohesion and angle of internal friction as the water content increases. Based on test data to derive a relationship between the number of freeze-thaw cycles, water content and shear strength parameters. And shear strength pebbly clay with increasing number of freeze-thaw gradually reduced.(2)Through different times of freezing and thawing, high liquid limit silt particles composed of fine particles of soil change is increasing. Little change in liquid limit plastic limit is reduced, reducing the plasticity index after the first increase. Dry density at three different moisture content of the sample cohesion increases and decreases the number of freeze-thaw, the internal friction angle is increased; samples with different water content in the same number of freeze-thaw and cohesion within friction angle are as dry density increases; samples with different dry density of cohesion with the water content decreases in the same number of freeze-thaw, the internal friction angle is increased. Not been high liquid limit silt thaw with increasing moisture content, shear strength gradually decreases and the amplitude attenuation increases, is very sensitive to the role of large diameter pores high liquid limit silt on the water. The greater the moisture content of the sample, the shear strength of the sensitivity of freeze-thaw cycles is greater.(3) Using ANSYS software clay gravel slope containing different number of freeze-thaw under simulated. Simulation results: After the safety factor of the number of different thawing significantly reduced, and the occurrence of slope after slope greater than the maximum displacement of thawing when not thaw slope instability failure, freezing and thawing have a greater impact on slope stability.