Abstract: A sampling device has a closed housing, a split-barrel sampler, an anvil, a drop hammer and a lifting device. The split-barrel sampler is mounted in and extends out from the bottom end of the housing. The anvil is attached to the top of the split barrel sampler. The drop hammer is moveably mounted in the housing and is located above the anvil. The lifting device is mounted in the top end of the closed housing to lift the drop hammer to a specific height above the top of the anvil. With the sampling device, the impact energy generated by the hammer is directly transmitted to the sampler through the anvil. The impact energy lost is minimized, and the accuracy of the Standard Penetration Test result is improved.

Abstract: A point-contact impact method used in the Standard Penetration Test (SPT) is disclosed. The method aims firstly to have the impact between the drop hammer and the anvil in the form of point contact and secondly to center the impact contact on the anvil face, such that the efficiency and the consistency of the energy transmission in the SPT greatly increase. With such a method, the ground condition of a specific site investigated by the SPT is able to be better determined. A device of the present method used in the Standard Penetration Test is a specially shaped anvil mounted on top of a rod, and the drop hammer is movably in contact with the anvil. The contact area of the anvil struck by the hammer is then limited and concentrated at the center. The impact between the hammer and the anvil is thus focused at or very near the center of the anvil, which reduces the energy loss during energy transfer from the hammer to the anvil.