冻融诱发平面滑移型岩质边坡失稳模型试验研究OA北大核心CSTPCD

In order to study the freeze-thaw instability mechanism of plane sliding rock slope,based on the similarity theory,the freeze-thaw test of slope model with main control fracture was carried out,and the response characteristics of temperature,frost heaving force,strain at the end of fracture,displace-ment of sliding body and acoustic emission in the whole process of freeze-thaw cycle were monitored.The results show that the temperature variation of different positions in the crack during the freezing and thawing process is consistent,which can be divided into six stages:rapid cooling and supercooling,latent heat release and phase change freezing,continuous cooling and freezing,crack ice heating and heat absorption,crack ice melting and complete melting;The peak value of frost heaving force decrea-ses with the increase of freeze-thaw cycles.During a single freeze-thaw cycle,the magnitude of frost heaving force is related to temperature.The peak value of frost heaving force appears in the freezing phase transition freezing stage,while the second frost heaving peak appears in the fracture ice melting stage;The displacement of the sliding body is small in the freeze-thaw 0～5 times,with a maximum of only 0.5 mm.The vertical displacement of the freeze-thaw6～14 times decreases slowly,and the hori-zontal displacement increases in a'step'shape,reaching a maximum of 3.8 mm.The displacement of the freeze-thaw 15～19 times remains basically unchanged until the 20 th freeze-thaw slope instability displacement increases instantaneously;The process of slope instability induced by freeze-thaw can be divided into:frost heave damage accumulation period,main control fracture expansion period,fracture expansion and penetration period,and sliding surface shear deterioration period.The evolution process of mechanical mechanism is'rock bridge locking','rock bridge-friction co-locking','friction loc-king',and friction unlocking slope instability.The research results provide some reference for the study of freeze-thaw instability mechanism of rock slopes in cold regions.