A boring layout should have a ability to establish geological sections (subsoil profiles) from which we should be able to determine the suitable sitting for the design. It is necessary for the stability analysis of the slide area that boring should establish full section. It is advised to include two extra boring to obtain UDS’s of the critical strata, on those places where detailed settlement, stability, or seepage analysis is needed. To delineate the extent and the suitable location for UDS’s boring, it is thought wise to provide sufficient preliminary borings.
The determination of the extent of the depth is from where the increase in the stress due to applied structural load is less than or equal to 10% of the effective over burden stress. The objective is to extend the preliminary boring to such a depth where it is able to penetrate through all unsuitable foundation strata, some of the examples are loose fills, peat and compact stratum of sufficient strength. Some of the bores are to reach the depth of 3 m into the rock stratum in order to satisfy that the it is not just a detached suspended boulder.