Considerations in the Undisturbed Sampling of Sands

The effect of sampling disturbance on the cyclic strength characteristics of sands is investigated by sampling from deposits of known dynamic characteristics prepared in the laboratory. Push-tube (Hvorslev fixed piston) sampling caused density changes (densification) of Monterey 0 sand with a relative density about 60 percent. A relatively larger relative density increase (about 10 percent) was noticed in the case of virgin samples as compared with about 6 percent increase for samples having a prior strain history. A combination of advance trimming and block sampling techniques caused little, if any, change in density. Some disturbance, resulting in only a partial loss of the resistance gained due to previous seismic effects, did take place. Based on the experimental results, an estimation of sampling disturbance effects for natural deposits is presented.