Study On The Characteristics Of Rock Falling In Dangerous Rock Under Earthquake Conditions And The Way Of Backfilling In Myeongdong

In the western part of China,the characteristics of rockfall disaster is that the rockfall disasters occur frequently and are highly destructive,which brings great security risks to the development of the railway industry.The arched open tunnel has the advantages of good impact resistance,which makes it work well in engineering practice.In this paper,the whole process of rockfall disaster is studied.The dynamic response of the rockfall collapse,the motion track of the rockfall,the impact force,and the single-pressure arched open tunnel protection structure are affected by the impact and the buffering effect of different backfilling methods are judged.The main research contents and results are as follows:(1)Mechanism of falling stone formation under earthquakeThe discrete element particle flow numerical simulation method is used to model,calculate and analyze the structure of the falling rock shed.earthquake is one of the conditions of the rockfall,the strength of the structural plane of the dangerous rock body is reduced under the earthquake,so that the dangerous rock body is separated from the parent rock to form the falling rock;the earthquake can accelerate the falling of the falling rock along the slope;the impact of the falling rock is positively correlated with the volume of the falling rock..The motion track of the falling rock can determine the threat zone of the falling rock.The length of the passive protective structure can be designed according to the range.The passive protective structure is adopted to strengthen the resistance to the falling rock when the tunnel spacing is narrow.(2)Dynamic response of single-pressure arched open tunnel under rockfallBased on the dynamic finite element method,a single-pressure arched open-hole structure model was established,and the dynamic responses of internal forces,strain rates,displacements,base reaction forces,energy and other indicators in different parts of the structure during the impact process were recorded to determine the structure during the impact process.The significant part of the force is also determined,and the vertical impact is determined as the most unfavorable impact mode,which provides a reference for design and construction work.(3).Study on backfilling method of single-pressure arched open tunnel under rockfallThe backfilling effects of the five backfilling methods commonly used in engineering were simulated and divided into impact phase and static balance phase.The buffering effects of five backfilling methods is scored in two stages.The best backfilling method is natural backfilling applied on the outside of the ear wall,concrete filled between the arch ring and the ear wall,backfilling on the upper side of the arch ring,the top surface of the structure is filled with clay..