Numerical Simulation And Analysis Of Strengthening Works For Manual Build Ultrahigh Embankment In Three Gorges Reservoir

In this paper, the proposed ultra-high filling roadbed is located in the affected areas of the Three Gorges reservoir, which is the part of Yun-Feng highway. For protecting environment and saving project cost, the original cloverleaf intersection was changed to be a high fill embankment which is built by the disposable ballast in the abuilding tunnel. The slope of roadbed was a arc overall, whose long is 220.00 m, maximal height is 56.20 m.The average thickness of the fill is 35m,and the total amount of disposable 1330000 m3. As the water and terrain conditions affects the building of the slope and makes slope high and steep, it is difficult to guarantee its stability,for which it will do some reinforcement. Based on this ultra-high filling roadbed, using PLAXIS finite element to do Numerical Simulation about the major strengthening works of the roadbed slope.The disposable ballast field to be set up according to the principle which is retaining before filling. To build a arched retaining wall at the foot of the roadbed slope , the height is 28 m. First, Based on the geological features in this region, establishing a geological model.Using conventional methods and PLAXIS FEM strength reduction to determine the soil pressure on the wall. The results showed that, the sliding surface of the slope is deeper in finite element analysis, which has a trend of landslides,so soil pressure is bigger. When designing to choose the bigger one between the two methods.As the pressure soil on the back of retaining wall is very large, the height of the wall is also larger, and retaining walls in the basement-weathered bedrock, so the basement will have a greater stress, the holistic stability of retaining walls may not be able to meet the requirements. Through PLAXIS finite element and on the basis of the strength reduction, a plastic analysis was been done for strengthening works,and determining the overall stability of retaining walls according to the stress , strain and plastic area, etc. The results showed that:First,after gravity retaining wall reinforced embankment slope, the wall along the basement has slippage, the foundation bearing capacity does not meet requirements, and retaining walls will overturn. Second, using four ranked pile to reinforce the wall, it has not slippage along the basement and the foundation bearing capacity also meet the request, but the anti-overturn of retaining wall still has some potential safety problems. Last, according to pile retaining wall numerical simulation results, using roof bolt to reinforce the walls.Then it has not slippage along the basement and the foundation bearing capacity also meet the request, while retaining wall has been achieved to the stability of anti-overturning.In this paper, using PLAXIS finite element to simulate and analyze the strengthening works of the ultra-high filling roadbed slope.Determining the reasonableness of this design works and providing consultation for the design of a similar complex strengthening works at the same time.