Study On Deformation Evolution And Instability Mechanism Of Rock Slope With Controlling Fissure Via Transparent Physical Model Experiment

The deformation and failure evolution process of rock slopes is usually controlling by internal long fissure(controlling fissure)during disaster incubation period.Therefore,sliding failure along the fracture surface is one of the most common types of instability and failure of rock slopes.Revealing the deformation evolution and instability mechanism of dominant fractured slopes is of great significance to the prevention and control of landslide disasters.Based on the transparent soil visualization model experiment technology,this paper conducted a model test study on the internal deformation and failure evolution process of slope with controlling fissure.Through DPIV technology and feature tracking technology,the internal multiple field information(displacement vector field,displacement velocity field,and strain rate field)during the slope loading process was obtained through analysis,Using this as a token,the spatiotemporal evolution mechanism of slope internal deformation and failure under the influence of leading edge and trailing edge dominant fractures is compared and analyzed,and then the progressive failure process of slope under different dominant fracture arrangements is simulated.The impact of leading edge dominant fracture inclination and trailing edge dominant fracture distribution location on slope internal deformation evolution and fracture expansion is analyzed.The main research work is as follows:(1)A new transparent similar material suitable for simulating rock was configured,and its mechanical property similarity was tested and discussed;A visual model test system for the deformation and failure of slope with controlling fissure was designed,which realized the non-contact observation of the entire process of slope internal deformation and crack expansion;Based on DPIV technology and feature tracking technology,the internal displacement field analysis and crack length measurement methods for transparent soil slopes were studied.(2)Based on a visual model test system,model tests were conducted on the evolution process of internal deformation and failure of the main controlled fissure slope,using displacement rate and strain rate as characterization variables for slope deformation and crack propagation,revealing the gradual process of internal deformation accumulation,crack initiation,propagation,and penetration of the main controlled fissure slope,and studying the spatiotemporal evolution mechanism of internal deformation and failure of the slope under the influence of the trailing and leading edge main controlled fissures.(3)By simulating the progressive failure process of slopes with leading and trailing edge dominant fractures,the internal deformation evolution mechanism of slopes with different dominant fracture arrangements was studied.The displacement rate of the upper part(slope surface)of the main fracture surface is much greater than that of the lower part(within slope),and the displacement from the slope surface to the inside slope has obvious zoning characteristics,indicating that the deformation development of the main fracture slope proceeds from the slope surface to the inside slope,and the overall deformation evolution process is similar to that of the non fracture slope,which can be divided into four stages:initial deformation,stable near uniform deformation,unstable accelerated deformation,and instability failure,As the inclination angle of the leading edge dominant fracture increases and the trailing edge dominant fracture approaches the slope surface,the slope stability decreases,which is manifested in the increase in the amount and rate of displacement of the slope surface,the acceleration of the slope deformation evolution process,and the advance of the overall sliding time.(4)Based on the displacement vector field,three types of displacement field are defined:tension type,shear type,and tension shear mixed type.From a mesoscopic perspective,the mechanism of slope crack propagation and penetration under different dominant fracture arrangements is studied.The leading edge dominant fracture tip undergoes tensile cracking and upward expansion due to traction,while the trailing edge dominant fracture tip undergoes tensile shear mixed cracking and downward expansion due to displacement;As the inclination angle of the leading edge main controlling fracture increases and the trailing edge main controlling fracture approaches the slope surface,the tensile stress at the tip of the main controlling fracture increases,the tensile trend changes from relative tension to absolute tension,and the expansion path is adjusted from upward(downward)expansion to slope expansion and penetration.