Study On Informational Dynamic Construction Technology Of Large Span Unsymmetrical Pressure Luwan Tunnel

In recent years, with the development of economy and the increasing traffic demand,more and more large span road tunnels are constructed, the mechanical system of the largespan tunnel and the stability of surrounding rock in construction process are taken seriouslyby the engineering. By the influence of topography and geology condition, large span tunnelis often under status of shallow cover layer and oblique loaded, So how to use the existedinformation construction technology to ensure that smooth construction of large spanunsymmetrical pressure tunnel is very meaningful.The clear span of under construction Luwan tunnel is achieved to14.9m, and the portalsof the tunnel has all been influenced to some extent by shallow cover and oblique load.Therefore this paper takes the shallow cover layer and oblique loaded section of Luwan tunnelin50provincial roads Liandu section as background, with the association method of sitemonitoring method and3D numerical simulation, the deformation and stress characteristics inconstruction progress of shallow cover layer and oblique loaded section is analyzed, thedynamic construction mechanical process of large span unsymmetrical pressure tunnel isresearched. And on this basis the reasonable excavation schemes of unsymmetrical loadedsection are calculated, gained a some practical significance research results.First the engineering geological environmental conditions of Luwan tunnel is beenanalyzed, the general situation of the tunnel design and construction characteristics ofunsymmetrical loaded section is summarized, and the dynamic information constructionscheme of Luwan tunnel is introduced in detail. Then the site measuring results is detailedanalyzed, construction mechanics characteristic of shallow cover layer and oblique loadedsection is researched, then the related change rule is summarized, the results point out theshallow cover layer and oblique loaded effect of left hole s more serious than that of the righthole.With the finite difference method software FLAC^3D, the dynamic mechanical process ofunsymmetrical loaded section is been simulated, the stress and deformation of surroundingrock and initial support are analyzed. The results point out that arch feet and arch waist indeep side of initial support suffer more stress. Finally, with the finite difference method software FLAC^3D, the reasonable excavationorder of left tunnel first or right tunnel frist, the reasonable excavation of curve drift headingand two-side wall drift heading method are researched. The results point out that excavationthe shallow buried side is the more reasonable method.