Research On The Characteristics Of Rock-rolling Hazards And Protective Structures On The High And Steep Slopes Of The Anjula Pass Of The Sichuan-Tibet Highway

Sichuan-tibet area is a high risk area for rolling stone disasters due to its special topography and climatic conditions.Through the investigation along the 318 national highway of south sichuan-tibet highway,it is found that the rolling stone disaster of sichuan-tibet highway is not only widespread,but also many anti-rolling stone measures have been seriously damaged and road safety is seriously threatened.In order to ensure the reliability of the Rolling Stones along the sichuan-tibet highway protection measures and road safety,the article is based on the Sichuan-Tibet Highway Basu to Ranwu,a key section of the rolling stone disaster as a background,mainly use the numerical simulation method,the motion law of rolling stone hitting the common slope of sichuan-tibet highway and the dynamic response of rolling stone hitting the door shed hole are studied,summarizes the sichuan-tibet highway to decorate a method each material rolling stone slope protection measures,and steel rolling shed hole is optimized.The main research results are as follows:(1)The sichuan-tibet highway common types of slopes mainly include: smooth rock,gravel,hard soil,soft soil slope or vegetation slope,slope model is established by Rockfall software,respectively for the Rolling Stones hit four slope motion process after 200 times of simulation was carried out,a rolling stone gathers the impact smooth rock,gravel,hard soil,soft soil slope or vegetation soil slope toe after jumping height greater than 5 m,respectively56%,22%,12.5%,2%,the proportion of the kinetic energy more than 40 KJ are 64.5%,35.5%,25.5% and 4% respectively,the slope is more hard,rolling stone after horizontal migration the farther the distance.It can be seen that the slope of rolling stone smooth bedrock is far more dangerous than other slopes,and the slope of soft soil or vegetation cover is relatively safe.(2)Due to the greater risk after the rolling stone hits the smooth bedrock,the key protection should be carried out.The soil spraying technology can be used to reduce the slope recovery coefficient and reduce the energy after the rolling stone hits.At the same time,a passive protection net is set at the foot of the slope.After the rolling stone impinges gravelslope or hard soil slope,individual rolling stone may threaten the road safety,can be in the slope foot and adjacent to the side of the road at the same time set up a passive protection network to intercept individual bounce height of the larger rolling stone,or in the rolling stone material source set up lower open curtain type active protection network;Soft soil or vegetation cover slope has better energy dissipation effect on rolling stone,the commonly used passive protection net can meet the interception requirements,only at the foot of the slope set up passive protection net can meet the requirements.(3)In sichuan-tibet highway Anjiula mountain south foothill damage to the door of the shed hole as the background,through field investigation and LSDYNA finite element software modeling,discover the cause of the shed hole damage mainly impact Rolling Stones too large beam,column,beam column joint stress concentration,and the Rolling Stones impact on a large number of accumulation in the shed roof board after you became a permanent load,stress concentration parts of the software simulation is mainly,beam-column joint in beam span,consistent with the structure damage.(4)Through setting has a slope of rubber cushion on the roof,optimize the original shed hole,after transforming the shed hole structure of the maximum equivalent stress reduced by72% compared to the original shed hole,rock fall below canopy ceiling board maximum deflection decreases 45%,rockfall impact decreases 62%,shed hole can significantly reduce the impact process,mechanical performance of the improved shed hole has an obvious advantage over the hole.After setting a reasonable slope cushion layer on the roof of the shed,the Rolling Stones can be prevented from piling up on the roof of the shed and becoming a permanent load.When the cushion slope ratio is 1:5,the energy dissipation effect is well combined with economy.