Settlement Calculation Method with Pile-Net Composite Foundation

Abstract

The post-construction settlement of subgrade is strictly limited in high-speed railway. Therefore, pile-net composite foundation is widely used for high-speed railway. The settlement calculation method with pile-net composite foundation is a common method which is used for calculation of pile-slab composite foundation at present. Based on both theoretical research and testing analysis, the results show that significant difference exists in the composite ground between the flexible and rigid foundation. The proposed settlement calculation method of rigid pile-net composite foundation is discussed for the first time with the current code in this paper. The analysis shows that the current code method cannot meet the actual situation under over-consolidated clay. Using the method of rigid pile composite foundation, the distribution of stress is derived according to German Recommendations for Reinforcements with Geosynthetics EBGEO (DGGT 2003). Using the Mindlin-Boussinesq uniting method can calculate the additional stress in the ground. Finally, settlement of the reinforced area and underlying stratum can be calculated by the method of e-lgp curve. This method can also be used to analyze parameters that influence the settlement, such as the pile spacing, the condition of pile cap, the length of pile, and stress history of soil. The distribution of soil settlement and additional stress with depth correspond to the actual situation, and the calculation results of settlement show that the new method is in accordance with the in-situ data.