Study on Adaptability of Initial Support of Tunnel in High Stress Horizontal Strata
Research purposes:The tunnel strata in Yichuan County of Menghua Railway are mostly horizontal sand and mudstone interbedded strata,the regional horizontal in-situ stress is high,under the joint action of in-situ stress and horizontal rock strata,the initial support of the tunnel occurs in a large area of peeling,cracking,falling blocks,and steel frame distortion,which brings greater safety hazards to the construction,and what type of measures to take for the high geostress horizontal rock strata is a problem that needs to be studied urgently.The four types of support types of conventional support,reinforced support,reinforced floor+long anchor,and limited resistance and energy dissipation support were studied.Combined with the 3DEC discrete element software and the actual deformation stress force measurement data in the field,the effects of the four types of support were compared and analyzed,and the engineering measures for rock strata with high geostress level were obtained.Research conclusions:(1)The cracking of the rock layer with high geostress level is mainly reflected in the peeling of the shotcrete of the vault,the falling of blocks and the distortion of the steel frame.(2)The single reinforced support parameter scheme and the reinforced bottom plate+long anchor support scheme have the effect on controlling the deformation convergence,but the arch still has the phenomenon of cracking and falling blocks,which cannot completely solve the construction safety risk.(3)The resistance-limiting energy-dissipating support can achieve the effect of releasing the pressure of the surrounding rock,and the initial support does not crack after the deformation of the resistance-limiting structure.(4)The use of resistance-limiting energy-dissipating support in rock formations with high geostress levels has achieved remarkable results in economy and safety,and the promotion and application effect is good.
horizontal layered rock massrock stresscrackprimary liningsupport resistant limiting damper(SRLD)
万方数据
维普
