In-site investigation and numerical estimation for bearing capacity improvement of very soft ground reinforced with geotextiles

This paper first describes the field investigation on the effect of bearing capacity improvement of the very soft ground reinforced with the composite geotextiles(non-woven fabric and geogrid) at the Chofu reclamation site near Shimonoseki, Yamaguchi Prefecture in Japan. Comparing the observed values of the mobilizing strain in geogrid with the filling work procedure with the analytical results by using the finite element technique proposed by Tanabashi et. al. (1992), the numerical simulation taking account of the earth spreading speed was carried out under the combination with the bulldozer's weight and the covered soil's thickness. Furthermore, the statical numerical simulation of real scale footing test was carried out varying the ratio of loading width to soft clay layer thickness, both with and without reinforcement and also both with and without the sand-mat layer. Finally, based on the results of these simulations, a rational estimation of the bearing capacity improvement and the deformation characteristics of the very soft ground reinforced with geotextiles and sand-mat layer has been proposed.