ABSTRACT
A load q = 1 covering one of the blocks will produce a vertical stress Ci • In other words, the 'influence value' of each loaded block is Ci. If the number of loaded blocks is N, and if the intensity of load is q per unit area, the total vertical stress at depth z below the center of the circle is
{jz = CiNq (6.24) The graphical procedure for computing the vertical stress {jz due to any surface loading is as
follows. Select some definite scale to represent depth z. For instance a suitable length AB in cm as
shown in Fig. 6.12 to represent depth z in meters. In such a case, the scale is 1 cm = dAB meters. The length of the radius RO.8which corresponds to (jz/q = 0.8 is then equal to 1.387 x AB cm, and a circle of that radius may be drawn. This procedure may be repeated for other ratios of Gz/q, for instance, for Gz/q = 0.7, 0.5 etc. shown in Fig. 6.12.
