Study On The Calculation And Selection Method Of Tangential Recovery Coefficient Based On The Traces Of Rockfall

Rockfall dynamic analysis is very important for disaster prevention and mitigation of rockfalls in mountainous areas.The interaction between the falling rock and ground is the main factor that affects the trajectory of the falling rock and the kinematic analysis.The selection of the recovery coefficient of the falling rock collision is extremely important for the analysis and calculation of the falling rock kinematics.Therefore,in order to be able to reasonably perform rockfall kinematics analysis and trajectory simulation,it is necessary to conduct in-depth research on the interaction between rockfall and the ground,that is,the rock-ground interaction and the selection and calculation of related core parameters.The research has certain theoretical significance for the analysis and prevention of the geological disasters of avalanches and falling rocks in mountainous areas.This thesis takes the rockfall disaster group in Zongling Town,Nayong County,Guizhou Province as an example.Based on the development of concentrated and highly active rockfall disaster groups and the remaining traces of the rock-ground interaction on the soft soil slope,the quantification of the rockfall-ground interaction is established.Evaluation system.Based on the Cattaneo & Mindlin contact theory and Hertz tangential contact theory,based on the assumptions that are in line with the actual and theoretical derivation of the site,combined with the real trace data of the rockfall disaster site,the tangential recovery coefficient calculation theory is derived,and the theoretical results are combined with the field data to optimize the core Recommended method for parameter selection.At the same time,the numerical simulation software Roc Fall is used to verify the rationality and reliability of the proposed method of parameter selection.The main research results of this thesis are as follows:(1)The cube-shaped rockfall in the study area has a strong shoveling effect on the slope surface.The impact marks left on the slope surface after the rockfall movement are more irregular in shape,the trace spacing is smaller,and there is no obvious peak height area of the rockfall bounce.The flake rocks that stayed vertically have more bouncing behavior and less dragging and sliding behavior.The field data indicators corresponding to rockfall quantitative indicators,slope quantitative indicators,and scar trace quantitative indicators are divided into three categories,and a quantitative evaluation index system for rockfall-ground interaction is established.(2)According to the Cattaneo & Mindlin contact theory and Hertz tangential contact theory,starting from the perspective of rockfall energy consumption,considering the loss of rockfall rotational kinetic energy and the conversion between translational kinetic energy and rotational kinetic energy,a method was proposed for the calculation method of the tangential recovery coefficient based on the traces left by the collision slope.(3)According to the characteristics of the soft soil slope in the study area,the tangential residual deformation and the quality of falling rocks are selected as quantitative indicators,the characteristics of the rock and soil layers on the slope are used as qualitative indicators,and the shape of the falling rocks and vegetation coverage are proposed as auxiliary indicators.The proposed method of recovery coefficient value afterwards has been optimized in terms of adding quantitative indicators,subdivision coefficient value range,and coefficient value accuracy.The Roc Fall software is used to verify its rationality and reliability.