MECHANISM OF GEOGRID REINFORCEMENT BASED ON PARTIALLY DEVELOPED SOIL ARCH EFFECT AND DESIGN METHOD

The mechanism of geosynthetic membrane effect is analyzed by utilizing geometrical and mechanical method,and the stress state of the embankment within the subsidence cupboard is deduced based on an assumption of an idealized slanted sliding surface,and the development of the shearing stress along the sliding surface is considered in the coefficient of active lateral earth pressure.The membrane effect and stress-strain state are coupled in the proposed calculation model.Then,a physical model test was performed to monitor the settlement and induced axial tensile strains of reinforcements,and the earth pressure,etc.A comparison of the test results to the proposed calculation model and several traditional design methods demonstrates that:the proposed method results are more close to the test results,which can take good care of the varying process of relative displacement and realistic slanted sliding surface.Because of different definitions of coefficient of lateral earth pressures,the vertical stress calculated from Terzaghi s method is small while that from Handy s method is large;For the strain of geosynthetic,the Giroud s method is considered to be too conservative and the Esponiza s is a little small,and the strain calculated from the proposed method is a little large,but it is reasonable when considering the serviceability and long-term creep of the geosynthetic.