In simulating the behavior of sandy soil under the cyclic loading condition using the multiple shear spring model, it is necessary to adjust the damping constant of the model. We describe a method for adjusting the constant in this paper. If you adopt the conventional Masing rule to decide the unloading curve of each spring, the entire damping constant of this model, which is superposition of those of all springs, would become larger than that measured in the laboratory for large strain level. Though the damping constant of each spring is controllable by amending the Masing rule, there is no obvious way to decide the constant of each spring. In order to reproduce the actual damping constant, we expressed the damping constant of each spring as a function of displacement at which unloading of the spring has started, and determined the coefficients of the expression from the actual damping constant. So we can amend the Masing rule for each spring so as to realize the damping constant for each spring. The method is adopted to the effective stress analysis program FLIP developed by the authors. In this paper we explain the method and show the results of the computer simulations by FLIP program
