Effect of water content on shear strength and small strain stiffness of red mudstone as subgrade fill material
Red mudstone fill material(RMF)has been widely used as subgrade fill material in southwest China.RMF exhibits high water sensitivity,from which the strength and small strain stiffness is strongly dependent on the water content.The precise estimation of strength and small strain stiffness plays key roles to evaluate the stability of the subgrade.However,the current study mainly focused on the mechanical behavior of RMF at optimal water content and saturated state,with few concentrated on the effect of water content.This paper presented a comprehensive experimental program including undrained triaxial tests and bender element tests to examine the strength and small strain stiffness,with particular emphasis on the effect of water content and confined pressure.Results indicated that the cohesion of RMF decreased significantly with water content,while only slight reduction was observed when RMF specimen became saturated.The magnitude of Emax increases with confined pressure at dry side.On the other hand,the effect of confined pressure on Emax is less than that at wet side.The stiffness would be underestimated by conventional triaxial tests,with an overprediction of stiffness degradation rate.It is recommended to related the strength and small strain stiffness with Emax.The ratio of Emax to qmax for RMF at low water content approaches that of stiff clay,which is still lower than the that of gravels.The ratio of Emax to qmax for saturated RMF is close to soft clay.A linear relation has been found applicable well for RMF and other geomaterials in double log scale,in which the model parameters are dependent on the type of materials.The results provide a reference for subgrade design.
red mudstonesubgrade fill materialshear strength behaviorsmall strain stiffnesscorrelation between strength and small strain stiffness
万方数据
维普
