Study On Stability Evaluation Of Surrounding Rock Of Xin’an Ridge Shallow-buried Unsymmetrical Tunnel And Its Lining Technology

This paper carries out the shallow-buried unsymmetrical pressure tunnel stabilityevaluation of surrounding rock and lining technology research. The research proves that it hasvalue of important engineering application. Research work take Xin’an ridge level V of thetunnel surrounding rock of shallow buried section from shiyan to tianshui as an object, adoptsthe method of combining theoretical analysis with field monitoring to carry out research work.Main conclusions as follow:(1) Determining the three main factors to produces unsymmetrical pressure load forhighway tunnel are construction factors, topographic factors, geological factors and gives away to define deep buried tunnel and shallow buried tunnel. Study the shallow unsymmetricalpressure tunnel surrounding rock load calculation method.(2) Studies have shown that the four main influencing factors of the shallow-buriedunsymmetrical pressure tunnel surrounding rock stability are the level of surrounding rock,strata dip angle, embedded depth of tunnel, and excavation sequence.(3) Based on Xin’an ridge tunnel shallow unsymmetrical pressure section, designed theadvance support, primary support and secondary lining of the left lane of the tunnel entrancelevel V shallow-buried unsymmetrical pressure section. In order to weaken effectsshallow-buried unsymmetrical pressure on the tunnel lining, the surface of shallow-buriedunsymmetrical pressure treatment is given.(4) Studied the reasonable construction method of Xin’an ridge level V of the tunnelsurrounding rock of shallow buried section by using FLAC3Dfinite difference software,numerically simulated the three conditions of method of up and down the steps, stay ring coresoil excavation, and the next method(CD method), research shows that in the next door is the best method for tunnel construction and has little effect on the stability of surrounding rockand is conducive to play the bearing capacity of surrounding rock.(5) Completed construction monitoring scheme design of Xin’an ridge tunnel shallowunsymmetrical pressure section. Field monitoring results show that the proposed liningstructure optimization designs the surface strengthening treatment measures and constructionmethod are feasible.