The Study On Strength And Interaction Behavior Of Soil Reinforced With Denti-Inclusions And Its Application

Reinforcement of grid with ribs has the advantage of the traditional geogrid and H-V reinforcement, whose reinforcing effect not only shows in the friction of horizontal bar, more importantly, but also the vertical inclusions that provides resistance to restrict the lateral displacements of soil. Therefore, reinforcement of grid with ribs can greatly improve the bearing capacity and stability of the reinforced structure compared to traditional reinforcement, which has important theoretical meaning and engineering application future. However, theory study is obviously behind the engineering practice, for example, its unclear reinforcement mechanism and immature calculation method, which need further study. In this paper, triaxial test, pullout test, model test, numerical simulation using PFC (particle Flow Code) and theoretical analysis are conducted to study the strength behavior and reinforcing mechanism of reinforcement of grid with ribs. The research work of this paper includes three aspects as follows:(1) The Effectiveness of reinforcement of grid with ribs was verified by triaxial test and pullout test. The advantage of reinforcement of grid with ribs compared with the traditional reinforcement is due to its lateral resistance generated by the vertical inclusions, which can greatly improve soil strength. Based on the limit equilibrium theory, the strength model and the ultimate pullout force model of reinforcement of grid with ribs were established, the contrast between the test results and calculated results show that both are in good agreement.(2) Pullout test is simulated using PFC^2D (Particle Flow Code in Two Dimensions)to analyz the particle displacement, force and the change law of sample's porosity which were difficult to observe in the experiments. The microscopic characteristics showed by stress field, displacement field were mainly discussed, and interface interaction mechanism of reinforcement-soil interface and displacement development characteristicsis were further revealed from microscopic viewpoint. Numerical simulation results show that: reinforcement of grid with ribs play an important role in the contribution for the growth rate of pullout force about 50%; the vertical inclusions have a great impact on the soil near reinforcement-soil interface, the soil particle in the front of the vertical inclusions tend to move upward, while the soil particle behind the vertical inclusions tend to move downward.The failure surface show ribs wavy in the reinforced structure.(3) Model tests of sand reinforced cushion by reinforcement of grid with ribs on soft ground were designed and four test cases were conducted to study the effect of reinforcement of grid with ribs on the soft ground.The test results show that reinforced cushion by reinforcement of grid with ribs can significantly increase the bearing capacity,reduce the settlement, and improve the mechanical behavior of soft ground. Under the same test conditions, the reinforcing effect of reinforcement of grid with ribs is much better than traditional geogrid.