双根无粘结预应力筋加筋体力学性能研究

Mechanical Properties of Reinforced Body with Double Unbonded Prestressed Reinforcements

为了研究双根无粘结预应力筋上施加的预拉力对加筋体力学性能的影响,采用缩尺模型试验研究,以钢砂作为填料,既满足了工程中无黏性填料的强度,又模拟了加筋体的应力状态。通过分级施加无粘结预应力筋的预拉力及模型上部的荷载,获得了加筋体的变形及挡板背部土压力的分布,并将试验结果与普通加筋体的测试结果进行了对比分析。研究表明:施加预拉力前加筋体的顶部沉降小于普通加筋体的顶部沉降;无粘结预应力筋上预拉力可以显著减小挡板的水平变形,且影响加筋体顶部的沉降,该影响与无粘结预应力筋的位置有关;堆载后挡板的水平变形和加筋体的竖向变形均变化不大;在施加预拉力过程中无粘结预应力筋之间基本无相互作用。

The mechanical properties of reinforced body with double unbonded prestressed reinforcements are affected by the pre-tension applied on it. In scale model tests,steel shot was adopted to simulate the intensity of cohesionless fill and the stress state of the reinforced body. The distribution of deformation in the reinforced body and the soil pressure on the back of slab were obtained through applying pre-tension on unbonded prestressed reinforcement and heaped load at the top of reinforced body step by step. The test results were compared with those of common reinforced body. Results revealed that the settlement on the top of the reinforced body in the presence of pre-tension was smaller than that of common reinforced body in the absence of pre-tension. The increment of pre-tension reduced the horizontal deformation of slab and affected the settlement on the top of the reinforced body,which depends on the position of unbonded prestressed reinforcement. Moreover,the horizontal deformation of slab and vertical deformation of the prestressed reinforced body changed little under heaped load. When applying pre-tension,there is almost no interaction between the reinforcements.