Study On The Engineering Technology Of High Embankment Embankment In The Ditch Section Of Mountainous Tunnel

Due to the influence of frequent water level fluctuation, steep slope, surface runoff, and great weight of embankment filler which is generally from slag tunnel material with complicated deformation property, geological disasters, such as overall or local settlement and slope instability, occur frequently in Three Gorges Reservoir region, where the high-grade highway traverses numerous tunnel gullies. The safety of project construction and operation is threatened frequently. To improve the stability of tunnel gullies high roadbed becomes an urgent problem to be solved.Based on the high fill+block slag dam project named Fengjie East Overpass, which is a part of Hang-Lan highway from Fengjie to YunYang, the design and construction techniques of high-filled embankment+supporting and retaining structure of subgrade of Badong group which reservoir tunnel slag material is used as road construction materials is studied, analysis of different steps width of retaining wall under horizontal stress and equivalent plastic deformation gets a conclusion that a draw step width of2-3m is recommended. Settlement analysis by a finite element ANSYS code is used. In the numerical model, the embankment is divided into8layers, and the "life and death element" is used to realize the special effect. Two-dimension numerical simulation of mountain tunnel gully embankment is performed to evaluate the influence rule of filling height, degree of compaction, horizontal displacement and maximum horizontal tensile stress of retaining wall and water level fluctuation. With the monitor of slope treated by grid slope protection, a good effect is obtained finally.Through the establishment of horizontal displacement reference network and vertical displacement of the benchmark network, continuous monitoring of dam and slope deformation shows that the horizontal and vertical displacement of the dam surface are small and irregular at present, and the change of force at internal point is negligible. It indicates that the dam is stable basically. And the horizontal displacement is big while the vertical displacement is small. The deformation of each hole is slow and increase continuously form hole bottom to the surface from bottom to the surface, and none abnormal deformation point is observed, which indicates that the monitoring part of roadbed slope is overall stability and no deformation zone appears in deep.In this paper, design and construction techniques of high-filled embankment+supporting and retaining structure of subgrade are studied by theoretical analysis, numerical simulation and deformation monitoring systemically. The results, which have important signification for the completion of project, provide technical support for the implementation of scheme of bridge road and the safe operation in the future. Since the high mountain tunnel in reservoir gully embankment roadbed uses a large number of waste earth from excavation as roadbed filler, compared with the bridge across way, it is economic, environmental protection. And it should be a popular structure form for the high-grade highway construction in the future. Research of the stability of high embankment tunnel gully on the effect of water at mountain area is of great significance to protect people’s life and property safety and to guide the project construction in Three Gorges Reservoir region.