Distribution-free method for estimating size distribution and volumetric frequency of rock joints

A method for estimating joint size distribution and volumetric frequency using three kinds of joint traces in a sampling window is proposed. The concept of joint center volume is proposed, which is defined by the shapes of the joints and a sampling window, joint size, and trace length. This method can be applied to general cases of joint survey and joint geometry including relatively small sampling windows compared with the joints, and any shape of joints such as circles, ellipses, rectangles or other polygons. The suggested method is a distribution-free estimation method, as it does not require any assumption of the joint size distribution type, or even of an upper limit on the joint size distribution.