In this study, the effect of near-field and far-field ground motions on the seismic response of the soil pile system is investigated. The forward directivity effect, which includes a large velocity pulse at the beginning of the velocity time history of the ground motion is the most damaging phenomenon observed in near-field ground motions. To investigate the effect of near-field and far-field ground motions on the seismic response of a soil-pile system, a three-dimensional model consisting of the two-layer soil, liquefiable sand layer over dense sand, and the pile is utilized. Modeling is conducted in FLAC 3D software. The P2P Sand constitutive model is selected for sandy soil. Three fault-normal near-field and three far-field ground motion records were applied to the model. The numerical results show that near field velocity pulses have a considerable effect on the system behavior and sudden huge displacement demands were observed. Also, during the near-field ground motions, the exceeded pore water pressure coefficient (Ru) increases so that liquefaction occurs in the upper loose sand layer. Due to the pulse-like ground motions, a pulse-like relative displacement is created in response to the pile. Meanwhile the relative displacement response of the pile is entirely different due to the energy distribution during the far-field ground motions.
随着季节的更换以及温度的改变，在季节性冻土地区易出现土的冻结和融化现象，从而造成地基土不均匀的胀缩，随之导致路基的不均匀变形，这直接影响到路面行车的安全性。潍坊地区属于轻冻区，通过分析季节性冻土病害的影响因素，阐释水热迁移模型，以潍坊某高速试验段设计道路为研究对象，通过FLAC 3D软件进行数值模拟，分别分析换填1.0m、换填1.5m、换填2.0m三种情况下对道路温度场、变形场、应力场的影响。结果表明：换填深度2.0m和换填深度1.5m对道路结构温度值几乎相同，从保温效果考虑和工程费用方面考虑，换填深度为1.5m最优；随着换填厚度的增大，竖向变形值随之减小，换填深度为2.0m时最小；而拉应力的范围和程度也减小并向右侧偏移。文章为季节性冰冻地区路基变形研究提供了一定参考。
随着季节的更换以及温度的改变，在季节性冻土地区易出现土的冻结和融化现象，从而造成地基土不均匀的胀缩，随之导致路基的不均匀变形，这直接影响到路面行车的安全性。潍坊地区属于轻冻区，通过分析季节性冻土病害的影响因素，阐释水热迁移模型，以潍坊某高速试验段设计道路为研究对象，通过FLAC 3D软件进行数值模拟，分别分析换填1.0m、换填1.5m、换填2.0m三种情况下对道路温度场、变形场、应力场的影响。结果表明：换填深度2.0m和换填深度1.5m对道路结构温度值几乎相同，从保温效果考虑和工程费用方面考虑，换填深度为1.5m最优；随着换填厚度的增大，竖向变形值随之减小，换填深度为2.0m时最小；而拉应力的范围和程度也减小并向右侧偏移。文章为季节性冰冻地区路基变形研究提供了一定参考。