The Forming Control Technology Of Horizontal Layered Rock Tunnel In Blasting Construction

Sedimentary rocks with layered structure are widely distributed in nature,accounting for about 66.7%of the land area,while in China the proportion is up to 77.3%.It has been a difficult problem for the construction of tunnel in layered rock of the project,such as the GUI Guang railway,Shuo Huang railway and Bao Xi Railway.But at present,the research on the influence factors of the horizontal layered rock tunnel blasting forming is not enough,and the understanding of the mechanism of the fblasting forming is still flawed.In the process of the design of blasting parameters,the design is not combined with the engineering characteristics of layered rock.For the above reasons,there is a series of phenomena,such as irregular outline of tunnel blasting,broken roof,lack of blasting,etc..those have a direct impact on the quality of smooth blasting of tunnel,which leads to the increase of project investment.Therefore,it is of great significance to study the blasting technology of horizontal layered rock tunnel,The article based on The Tong Mashan tunnel of GUI Guang railway,conducted the research as bellow:(1)Comparison of horizontal layered rock tunnel forming under static and dynamic load is based on 3DEC discrete element software,analyzing the influence of different factors on tunnel forming,concluding that the space of structural plane and the degree of structural plane influence forming on the tunnel vault.(2)Using LS-DYNA software with ALE algorithm to realize the fluid solid coupling,analyzing the spread of stress wave at structural plane and rock crack formation,proved that the blasting mechanism of the tunnel with different space of structural plane,the degree of structural plane and the rock hardness,laying the foundation for smooth blasting parameter design of layered rock.(3)analyzed difference of blasting forming in different positions of horizontal layered rock tunnel,modifying the range of fracture zone.Presenting the design method of smooth blasting parameters of horizontal layered rock tunnel,and also gives the relevant auxiliary engineering measures.