The equivalent linear dynamic behavior of soil-pile interaction during earthquake has been used, as indicated in Fatahi and Tabatabaiefar work. The shear behavior of the grout annulus, during relative shear displacement between the pile/grout interface and the grout/soil interface, is described numerically by stiffness, cohesive strength, friction angle, and exposed perimeter. The normal coupling springs can simulate the effect of the host medium squeezing around the pile. The behavior of the normal coupling springs includes the ability to model load reversal and the formation of a gap between the pile and the grid. The normal and shear behavior of the pile-grid interface is cohesive and frictional in nature. The coupling springs are nonlinear, spring-slider connectors that transfer forces and motion between the pile and the grid at the pile nodes (by way of the link emanating from each pile node). Piles interact with the soil via shear and normal coupling springs. Finally, the stress-strain response of the whole pile is obtained by the integral accumulation effect. The pile is divided into microsegments of equal length, which were used in the elastic-plastic analysis. During the interaction of pile and soil, the pile bears the axial pressure, axial friction force, and transverse shear. The pile is simulated by the pile element in the FLAC3D and set at the center of the model. The results are expected to provide further insight into the underlying pile-soil interaction mechanism and the load transferring law of pile.įLAC3D is used to establish the 20 m × 20 m × 20 m numerical model, with 4 m underconsolidated soil at the upper part and 16 m consolidated soil at the lower part (Figure 1).
Flac3d frume software#
In the current study, we used the numerical software FLAC3D to establish an underconsolidated, soil-pile model and analyze the response processes of the pile side friction force, pile axial force, and soil under seismic load. Hakami used FLAC and FLAC3D to simulate a comprehensive pump test at Sellafield and predict the hydromechanical consequences of the sinking of a shaft. Cai applied FLAC and Phase 2 to analyze tunnel excavation problems. At present, FLAC3D, a nonlinear explicit finite difference program that considers the mechanical behavior of soil-pile interaction, has been widely used in geotechnical engineering. depicted different effects on the seismic response of moment-resisting building frames and lateral seismic response of building frames considering dynamic soil-structure interaction effects. Thus, examining the response of pile-soil structure under seismic load is important Tabatabaiefar et al. These previous studies have mainly analyzed the pile-soil response under static force, but pile engineering can be located in an earthquake-prone area. Qualitative experimental results have been obtained. Theoretical analysis, as well as laboratory and in situ experimental methods, had been used by several studies to establish interactional models of pile and soil. Therefore, the mechanism of a pile in underconsolidated soil and the distribution of the positive and negative friction forces should be examined considering its significance in engineering design. Given the pulling effect of soil, the negative friction force on the pile side will reduce its carrying capacity, causing engineering instability. If the settlement of the soil is greater than that of the pile, the pile is pulled down by the soil, and negative friction force is produced.
If the pile is driven into consolidated soil and the settlement of the pile is greater than that of the soil, the pile is supported by the soil, and positive friction force is produced. Pile foundation is widely used in geotechnical design as a reinforcing structure.
The response processes of the pile side friction force, the pile axial force, and the soil response under seismic load are also analyzed. In this paper, the nonlinear, explicit, and finite difference program FLAC3D, which considers the mechanical behavior of soil-pile interaction, is used to establish an underconsolidated soil-pile mode. However, many pile projects are located in earthquake-prone areas, which indicate the importance of determining the response of the pile-soil structure under seismic load. Previous studies have mainly focused on the interaction of pile-soil under static condition. If the settlement of the soil is greater than the pile, the pile is pulled down by the soil, and negative friction force is produced. Piles are widely used as reinforcement structures in geotechnical engineering designs.