Study On The Stability Evaluation And Treatment Of Dangerous Rocks

Dangerous rock disasters are common karst geological disasters in my country.Due to the irregular shape,complexity and uncertainty of the distribution of dangerous rocks in karst areas,the prediction of the stability of dangerous rocks has always been a difficult problem in engineering practice.The theoretical calculation formulas and numerical simulation results of the stability of dangerous rocks in the current engineering specifications often have certain errors with the actual situation.Based on the outdoor rockfall test and the 1:10 indoor scale simulation rockfall test,this paper studies the impact of rockfall quality,shape,damping coefficient and other basic parameters on the rockfall trajectory.The OBTE rockfall impact force test and the camera extract the rockfall trajectory in the test.Impact force,motion speed,bounce height and other motion parameters,derive the motion equation of falling rock trajectory.Through Rocfall numerical simulation modeling,the desirability and difference value of simulation and test results are verified,so as to analyze the stability of the dangerous rock in Diecai Mountain of Guilin and propose a treatment plan.The following main conclusions are obtained:1.Comparing the outdoor rockfall test and the indoor rockfall test,it is concluded that the movement modes of the rockfall are mainly rolling,bouncing and flying,and the sliding mode rarely appears;the quality of the rockfall has an impact on the rockfall offset,but has a small effect on the rockfall offset ratio;In the rock falling motion mode,the offset of the alternate mixed motion of the bounce and rolling modes is greater than that of the single bounce or rolling mode;the greater the "anti-terrain interference ability" of the large-mass rock falling on the influence factors such as surface fluctuation damping.2.In the Rocfall numerical simulation,the simulated rockfall reaches the farthest distance and the number of bounces is greater than the test result.The bounce height is greater than 15-25% of the test result.The energy generated by the impact force of the rockfall is higher than 25%-35% of the test result.This is related to Rocfall's setting that the shape of the falling rock is a mass point,and under the same conditions,ignoring the influence of shape and other factors,indicating that the value of the past numerical simulation is generally larger than the actual value of the rockfall.3.By comparing the outdoor rockfall test and the indoor simulated rockfall test with the rockfall path of the Rocfall software numerical simulation,the results of the test are smaller than the numerical simulation,but for the actual project,the error is within the acceptable range of the engineering design,so Rocfall is adopted.Software numerical simulation is of significance to actual engineering case analysis and research.4.According to the above conclusions,the dangerous rocks of Diecai Mountain in Guilin are studied,the special geological environment and structural conditions in the area where the engineering geology of the dangerous rocks are currently developed in the study area are ascertained,and the stereo graphic projection analysis method is used to evaluate the stability of the typical dangerous rock monomers.Deduce the damage under different load conditions of slumping dangerous rock,tipping dangerous rock,and falling dangerous rock.The analysis results show that the slope of the rock mass in the study area is basically stable to under-stable.5.Taking the section of the under-stable dangerous rock in the study area as the calculation section,the Rockfall software is used to numerically simulate the trajectory of the rockfall after its instability,and the relationship between the final stop point of the rockfall and the distance of horizontal movement is determined.The self-weight + rainstorm or continuous rainfall conditions are selected as the design conditions,and the reasonable selection of the optimal slope protection facility location,the optimal protection standard height,width and other rockfall slope protection and prevention methods are discussed.A comprehensive treatment plan combining "mainly,passive network as a supplement".