The Comparative Study of Single Pile Bearing Characteristics in Calcareous Sands Foundation and Quartz Sands Foundation Based on Model Experiment

The bearing characteristics of single steel pipe pile in calcareous sands foundation and quartz sands foundation with different relative compactness are compared and analyzed by the model tests of single steel pipe pile in two kinds of soil media in laboratory. The test results show that the bearing behavior of single steel pipe pile is quite different between calcareous sands and quartz sands. Pile end forms of single steel pipe pile have little influence on the bearing capacity, especially in the sands foundation with high relative compactness. Increasing the relative compactness of foundation soil has obvious effect on improving the bearing capacity of single steel pipe pile. But the bearing capacity of single steel pipe pile in calcareous sands is much lower than that in quartz sands in the same relative compactness. The lateral friction resistance of single steel pipe pile in quartz sands is much larger than that of calcareous sands. The lateral friction resistance of single steel pipe pile in calcareous sands does not increase significantly with the increase of relative compactness; But the lateral friction resistance of single steel pipe pile in quartz sands increases significantly with the increase of relative compactness. In calcareous sands foundation, the ratio of load sharing on the side of single steel pipe pile is small, and the load on the pile top is mainly borne by the soil at the pile end, and it is manifested as friction end bearing pile. In the quartz sands foundation, the axial force of the pile decreases rapidly along the pile. And the faster the axial force of the single pile of the steel pipe is decayed with the smaller compactness of the quartz sands..