Patent ID: 7201540
Filing Date: 2007-04-10
Classification: E02D

Abstract:
1. A construction process for a composite pile foundation which consists of an expanded belled base and a pile shaft, the construction process comprising the steps of: a) Aligning a pile tip at a preset pile location and place a casing at the top of the pile tip; b) Lifting a heavy hammer to enter the casing, repeatedly lift it to reach a given height and simultaneously back press the casing, let it fall freely to ram the pile tip and the soil until a hole forms at the pile location; c) Lifting a heavy hammer higher than a feed inlet of the casing and fill solid material into the casing through the feed inlet; d) Ramming the above-mentioned solid material and repeat the filling and ramming operations; e) The input of the above-mentioned solid material is controlled according to the following designed elevation and the total penetration of three blows: measuring the penetration of three continuous blows on condition that no material is being filled, if the penetration per blow is less than or equal to the penetration of the previous blow and the requirement of the design specification is met, stop filling; otherwise, continue filling and ramming; f) Filling graded aggregate or stiff consistency concrete, repeatedly ramming it to form the expanded belled base at the bottom of the pile hole; g) Pulling out the casing; h) Aligning the pile shaft at the pile hole and repeatedly back pressing and blowing slightly with the heavy hammer to drive it into the pile hole and fix and connect it with the expanded belled base; i) Forming the composite pile foundation.