Experimental Research On Working Performance Of Soil-nail With Mortar-bonded GFRP

The traditional materials reinforcement has been widely used in the soil nail support project. However, the bad corrosion resistance of the reinforcement is the hidden trouble in the anchor project. Glass fiber reinforced plastics (GFRP) has many advantages such as high strength,light weight, good corrosion resistance, low relaxation, electromagnetic resistance and so on. GFRP as a new composite materials has higher performance price ratio. If the GFRP can replace reinforcement, many problems of the reinforcement soil nail will be solved easily.The indoor model experiments were introduced to study the working performance of soil-nail with mortar-bonded GFRP. The relation between the displacement and the pull-out load, the changes of axial force along the length at the different load level and the the influence of the overlying load on the ultimate pullout load were investigeted. Then, the interface bond stress between the soil nail and its surrounding soil body, the transferorming mechanics of the axial force and the relation between the ultimate pullout load and the overlying load were analyzed. The experimental results illustrated that the relation between the displacement and the pull-out load can be described with the hyperbolic function, and there exists the dilatancy effect in the interface between the soil-nail and its surrounding soil body for the soil-nail in the dense soil.The pull-out bearing capacity of soil nail is a key parameter of the soil nailing design, but the extent of its computational solution by the empirical formula proposed by the relational standards is remarkable. Based on the assumpution that the friction strength of the interface between the soil nail and the surrounding soil follows the Mohr-Coulomb criterion and considering the soil dilatancy effects, the analytical solutions for calculating the skin friction and axial force of the soil nail were obtained, accordingly the formula for evaluating the pull-out bearing capacity of soil nail was suggested. The results of the proposed model are in good agreement with results of pullout tests..