DEFORMATION AND FAILURE MECHANISM OF GEOSYNTHETICREINFORCED SOIL RETAINING WALL SUBJECTED TO VERTICAL LOADING

Abstract

Geosynthetics such as geogrid or geotextile are usually applied in practical field for reducing displacement of soil structures and earth pressure acting on structures and increasing bearing capacity of foundations. The deformation and failure mechanism of the ground reinforced with geosynthetics is, however, not fully clarified. In the present study, mechanical behaviour of geosynthetic-reinforced soil retaining wall is investigated and the reinforcing mechanism by geosynthetics is discussed through two-dimensional laboratory model tests and their corresponding finite element simulations. In the model tests, mass of aluminum rods is used as ground which shows mechanical characteristics similar to that of medium dense sandy soil, and tracing paper having almost no bending stiffness is used as reinforcement material. The simulations are carried out using elastoplastic subloading t_ij model (Nakai and Hinokio, 2004). The model suitably can considers the influence of intermediate principal stress on the deformation and strength of soils, dependence of the direction of plastic flow on the stress paths, influence of density and/or confining pressure on the deformation and strength of soils. Several tests are carried out varying the arrangement, length and number of the geosynthetic-reinforcements. It is discussed that the effectiveness of geosyntheticreinforcements mainly depends on whether they increase both internal stability, which is local stability within the reinforced ground, and external stability, which is overall stability of the surrounding ground. The results obtained from the numerical analyses show qualitatively good agreement with the results of the model tests.