Effect of Underground Void on Foundation Stability

Abstract

The effect of underground void on the stability of shallow foundation supported by a compacted clay was investigated by using a three‐dimensional finite element computer program. The clay soil was a commercially available kaolinite which was compacted to 95% compaction of the standard Proctor compactive effort. The analysis was made for different conditions including footing shape (square and strip footings), void shape (continuous circular and cubic voids), orientation of continuous void axis with respect to strip footing axis (parallel and perpendicular directions), and void location. Results of the study indicate that footing stability will be affected by the underground void only when the void is located above the critical depth. The critical depth is not a constant but varies with the shapes of footing and void, void orientation, void size, and soil type. When the void is above the critical depth, the bearing capacity of the footing will decrease with decreasing distance between the footing and the void.