Abstract: This paper presents a case history of the supporting design of a deep excavation with a distance of 20.6 meters to the existing basement. The net spacing between the piles of two adjacent excavations was only 13.2 meters and the ground anchor option was not feasible. The improved method value engineered the original design of double pile option with the combination of soil unloading and sloping. The improved method was proved to be a safe and costeffective method.

Key words: adjacent deep excavations, shallower excavation followed by eeeper excavation, optimized construction