A modification scheme reforming original unqualified piles as composite foundation

摘要

Two bungalows were to be built, in which the span is 60 m X24 m, and vibrator sunk piles with Φ 377mm diameter were adopted to improve the soil-foundation. The design value of vertical ultimate carrying capacity of single pile P_u is 420 kN, but the actual test values of that are 120 kN～420 kN, and could not satisfy design requirement. Therefore, the soil-foundation should be improved. Based on analysis and comparison carefully, a modification scheme reforming original piles as rigid pile composite foundation is suggested. The calculation results show that the bearing capacity f_k of composite foundation is more than 100 kPa. while the corresponding barn foundation settlement is about 80mm, which satisfy the bearing capacity and allowable settlement of buildings, respectively. Moreover, the maximum moment of pile body under the load of loose grain in barn is 25 kN*m, and slightly less than that of pile resistance. All of the above results illustrate that it is feasible to improve the barn soil-foundation by the suggested modification scheme. The rationality of the presented scheme is testified by practical effect.