Abstract
An evaluation method in which the reinforcing effect on geogrid-reinforced soil can be divided into tensile effect and confining effect is proposed. The confining effect is one component of the reinforcing effects and is dependent on the tensile force of geogrid. The validity of the method was verified by the results of a series of new laboratory tests. Based on the proposed evaluation method of the reinforcing effect, failure criterion on the geogrid-reinforced soil is defined and Mohr's stress circle at failure is formulated. The new design method in which the partial safety factor is introduced into Mohr's stress circle on the reinforced soil is proposed. The partial safety factor is defined as a ratio of the radius of Mohr's stress circle on reinforced soil in design condition and the distance between the center of the stress circle and failure criterion on reinforced soil. Finally, as a examples of design of a geogrid-reinforced retaining wall, the results obtained by using the proposed method and the current method which introducing the tie-back wedge method based on Rankine's active earth pressure theory are compared. It becomes clear that the current design method is safer than the proposed design method.
