Study On The Formation Mechanism Of Talus Slope On The Sichuan-tibet Line

The talus slope is a non-zonal landform formed by gravity and weak erosion of the slope.The Sichuan-Tibet line area has strong freezing and weathering,high seismic intensity and seasonal freezing and thawing,which is the generation and development of the cuttings slope.The conditions are provided so that the cuttings slopes are widely distributed along the Sichuan-Tibet line.The existence of cuttings slopes seriously threatens the stability of the slopes and leads to the safety of the line being challenged.Studying the formation mechanism of cuttings slopes can further deepen the understanding of cuttings slopes and help the subsequent support engineering design The development is of engineering significance.This paper focuses on three important aspects of the formation mechanism of debris slope: freezing duration,freezing intensity and freeze-thaw frequency,laboratory experiments are conducted to study the formation mechanism of cuttings slopes.The main contents of the work are as follows:(1)By simulating the climatic environment of the alpine mountainous area and the climatic environment of the cloudy and sunny slopes on the Sichuan-Tibet line,corresponding experimental programs are proposed to simulate the freezing and weathering process of rocks under different conditions,and the simulation results are good.(2)A conventional freezing and weathering simulation experiment was designed to reflect the freezing and weathering process of a relatively flat slope.By comparing and analyzing its physical and mechanical indexes and the change law of apparent damage with freezing and weathering,it was found that the quality,longitudinal wave speed,The uniaxial compressive strength and elastic modulus are reduced,and the mass loss rate and the longitudinal wave velocity change rate continue to increase,the apparent damage is not obvious,and there are some cracks with 0.02 mm opening.(3)The shadow and sun slope effect simulation experiment was designed to reflect the different freezing and weathering modes of the shady and sunny slopes in the alpine mountainous area,and to explore the different formation mechanisms of the cuttings slope under different slope conditions.The shady slope simulation and the sunny slope simulation physics The change trend of indicators and mechanical indicators is consistent with the conventional freezing and weathering simulation experiment,but the apparent damage of the sun slope is the most obvious.30 years of freezing and weathering can completely break the rock sample on the sun slope and produce cuttings of different sizes.This is consistent with the fact that the sun-slope cuttings slope is more developed in the actual environment.(4)Experiments show that mudstone and sandstone have different weathering damage modes.Sandstone fissures develop along the bedding,and eventually the fissures are connected,resulting in the fracture of the rock sample,and the surface area of sandstone particles is large;the mudstone does not produce obvious fissures,but the rock Small holelike defects will appear on the surface of the sample,and the small holes will communicate with each other to form large holes with depth.Different damage modes will produce different types of cuttings.After the rock sample is weathered,the mass loss will cause surface shedding,and then the block will fall off and accumulate in place,and the block will be further weathered to produce cuttings with different particle sizes.,The old and new weathering proceeded at the same time,and the cuttings slope was formed and developed continuously.