Abstract
In engineering, to prevent damage of boulders due to their rolling down from slope, it is necessary to know that the rock is part of rock masses or a boulder and how deep it penetrates into the ground. According to authors' experiments, some interesting facts are found. The high frequency waves propagate with a very good directivity and the corresponding surface wave sharply decays. Based on above facts, a new portable nondestructive test system is made. Just using a steel hammer to hit the rock surface, the size of boulder in sensor's direction can be directly calculated in situ from reflection wave. Aim of this article is to present some results of indoor experiments and field tests obtained by this new system.
