Abstract
In general, rocks are oxidized and weathered when they are exposed to the surface of the earth by natural erosions or man-made excavations. As a consequence, the strength of rocks that suffered such weathering decreases in the end. Provided that a new method which can estimate weathering thickness of rocks nondestructively, simply and quantitatively in the fields is developed, it is expected that the method is useful for the practical fields such as engineering geology, geotechnical engineering and so forth.
In order to develop a new estimation method for weathering thickness of rocks like boring cores or relatively shallow weathering layers of outcropping rock masses, the authors produced four kinds of man-made weathering rocks modeled on natural weathering rocks. Then a series of Equotip rebound hardness tests was conducted by using man-made weathering rocks. Furthermore, an experimental investigation was carried out by taking notice of especially weathering thickness of man-made weathering rocks and the ratio of weathering layers to nonweathering layers in rebound hardness. In this paper, firstly the man-made weathering rock model by which weathering thickness of weathering rocks and shallow weathering layers of rock masses can be estimated is explained. Secondly, some investigation results of the method for producing weathering layers of man-made weathering rocks and homogeneity of produced weathering layers are reported. Lastly, a new method for estimating weathering thickness of man-made weathering rocks nondestructively, simply and quantitatively is suggested by using rebound hardness of man-made weathering rocks, weathering layers and nonweathering layers, respectively.
