Experimental Study On The Position Of Single Unbonded Prestressed Reinforcement For Mechanical Properties Of Reinforced Body

Unbonded prestressed reinforced earth technique is mainly control the deformation of reinforced body through active constraint by applying pre-tension to prestressed reinforcement.In this paper,the stress distribution and working behavior in the reinforced body are studied by the reduced scale model test,the distribution and interaction of the earth pressure acting on the panel as well as the earth pressure in the vertical section near the reinforcement strip area were deeply analysed in reinforced body,the distribution regularities of horizontal earth pressuress caused by pretention force between the panel and side pressures palte in prestressed reinforcement layer were studied.At the same time,the effect of prestressed reinforcement on the structural deformation and the strain of the reinforcement strip was studied by using the ordinary reinforced earth retaining wall as the contrast.The steel filler was adopted to simulate cohesionless filler in the model test,which solved similarity ratio of the scaled model.The reinforced body of single prestressed reinforcement fabricated model test was carried out,three kinds of conditions were designed for the location of prestressed reinforcement,single prestressed reinforcement were arranged at second layer,third layer and fourth layer respectively,the ordinary reinforced earth retaining wall were also complate at the same time.The results are as follows:(1)In the process of filling,the rest of the wall back earth pressure measured are close to Rankine active earth pressure in addition to the reinforced layer in the four kinds of conditions,and the lateral earth pressure at the section position are close to the earth pressure at rest.The increment ratios of horizontal earth pressure at corresponding position caused by the pre-tension in the lower layer and upper layer adjacent to prestressed reinforcement are the same under the same condition.(2)The pre-tension influences the horizontal stress of the filler through the panel and the side pressure plate,The influence range reach the maximum at the middle position of prestressed reinforcement because of the stress dispersion effect,but the main influence range is the prestressed reinforcement layer and its adjacent layers.The effect on the horizontal earth pressure of the filler between the panel and the side pressure plate caused by the pre-tension conforms to the quadratic curve law along the length of prestressed reinforcement.(3)Under the action of pre-tension,the stress level of the prestressed reinforced layer and its adjacent layers is obviously lower than the rest layers,that is,the unbonded prestressed reinforcement technology can improve the load carrying capacity and safety performance of the reinforced body structure.(4)By contrasting the displacement of panel,the settlement of the roof and the strain value of the reinforcement strips in each layer in reinforced body with that of the ordinary reinforced earth retaining wall,it can be seen that the stability of reinfored body is greatly improved under the action of pre-tension,which proves the excellent performance of the unbonded prestressed reinforced earth technique in the reinforced earth retaining wall.At the same time,when compared with the working behaviors of the reinforced structure in each conditions,it can be confirmed that the structural performance is most stable when the prestressed reinforcement arrangement at the panel near the middle position of third layer.