Research On Anchoring Mechanism Of Reinforcement Wrapped And Design Method For Reinforced Soil Retaining Wall

The reinforced soil retaining wall have been applied more extensively in highway and high-speed railway roadbed in our country because of superior performance and economic environmental protection.The interior of reinforced soil retaining wall is divided into active area and anchorage area with potential rupture surface as the boundary.The length of reinforcement in the anchorage area is the effective anchoring length and shall reach the minimum safety length to ensure the pull-out stability of the retaining wall reinforcement.However,due to the limitation of construction space in practical engineering application,it can not lay enough length reinforcement to the standard design position.This brings the problem that the reinforcement in the reinforced soil retaining wall can not meet the design requirements due to the limited construction space conditions.For reference to British BS8006 specification,the wrapping of reinforcement free end in anchoring area is set up to solve this problem.In this paper,the anchoring mechanism of the wrapping of reinforcement free end of reinforced soil retaining wall is studied by the pull-out test,laboratory scale model test and numerical simulation.The influence of the wrapped length,wrapped height and tensile stiffness of reinforcement on the reinforced soil retaining wall is discussed,and the working characteristics and design methods of the wrapping of reinforcement free end of reinforced soil retaining wall under static load are deeply analyzed,so as to provide reasonable and effective theoretical support for the design and construction of reinforced soil retaining wall under insufficient space.The main conclusions are as follows:（1）The pull-out test of the wrapping of reinforcement free end shows that the pull-out force of the wrapping of reinforcement free end was higher than that of the reinforcement unwrapped under normal load,and increased with the increase of the normal load.Under normal load,the friction between soil particles and reinforcement increased,which further promoted the interaction between reinforcement and soil,limited the neck shrinkage of reinforcement,and improved the anchorage force of reinforcement to prevent it from being easily pulled out.（2）The scale model test shows that the wrapping of reinforcement free end of reinforced soil retaining wall has good control effect.The wrapping of reinforcement free end can provide more effective anchorage length and the space condition is not high.Increasing the reinforcement wrapped length was beneficial to restrain wall deformation and vertical displacement at top of retaining wall.The control effect of l/h=2.00 was the best.The stability of reinforced soil retaining wall was less affected when only the reinforcement wrapped height is increased.（3）The numerical simulation shows that the tensile stiffness of reinforcement was the main factor affecting the stability of reinforced soil retaining wall.As the tensile stiffness of reinforcement increased from 3000k N/m to 6000k N/m,the vertical earth pressure,the horizontal displacement of wall and the vertical displacement at the top of retaining wall all change.In particular,the horizontal displacement of wall and the vertical displacement at the top of retaining wall decreased significantly,within the range of 35.48%-45.60%.Increasing the tensile stiffness of reinforcement was beneficial to restrain the deformation of reinforced soil retaining wall and improved the stability of reinforced soil retaining wall.（4）In this paper,the expression of the relation between the ratio of wrapped length to wrapped height of the reinforcement l/h,the pull-out force T_ki and the normal stressσ₁ at the wrapping of reinforcement free end of reinforced soil retaining wall was presented.It was easy to get the pull-out force of the wrapping of reinforcement free end,which provided preliminary suggestions for the actual design work.