Simplified method for settlement calculation of rigid pile composite foundation in soft soils

To find a simple and precise settlement calculation method for rigid pile composite foundation is still an urgent problem which is not solved as yet. For the settlement calculation of rigid pile composite foundation in soft soils by using the existing standard method, the total settlement can be the sum of reinforced area and substratum, the improvement of composite modulus in the reinforced area can be obtained by the bearing capacity ratio of compound foundation to natural foundation. In fact, the calculated results of settlement are usually too large because the inadequate improvement of composite modulus by using the above method. It is put forward that the reasons for this situation are the unreasonable hypothesis in formula derivation that the pile-soil stress ratio is equal to the pile-soil bearing capacity one. For the settlement calculation of rigid pile composite foundation in soft soils, a simplified method is proposed that the settlement of reinforced area can be the sum of pile settlement and cushion compress settlement when the pile tip is placed at reliable bearing stratum. The calculation of engineering examples shows that the simplified method is simple and precise, and it can provide an effective and practical calculation method for engineering practice.