季节冻土区光伏支架螺旋桩基的冻胀数值分析研究

Numerical simulation on anti-jacking-up performance of helical piles of photovoltaic stents in seasonal frozen region

利用有限元软件COMSOL自定义模块功能,将建立的水热力三场顺序耦合模型导入,模拟二维轴对称条件下多种螺旋桩在土体冻结过程中发生的冻拔,并设置光滑桩作对比.在冻深达到桩长全长时,全螺旋小叶片桩具有良好的抗冻拔效果(仅为光滑桩的19.5%).使用COMSOL内嵌热应力模块,模拟三维条件下螺旋桩抗冻拔过程,并与室内试验结果作对比.结果显示冻深只有桩长一半时,双螺旋小叶片桩明显减少桩体冻拔量.表明:通过数值分析可比选出抗冻拔的最优桩型,对于现场试验的光伏支架螺旋桩型设计提供参考.

Based on custom module of COMSOL,by introducing moisture-heat-stress sequential coupling model established,the jacking-up process of different helical piles under two-dimensional axisymmetric condition is simulated with using smooth pile for contrast. When the frost depth reaches full length of the pile,small-blade helicaled pile performs well in anti-jacking-up（ 19. 5% of that of smooth pile）. The embedded thermal stress module is used to simulate the anti-jacking-up process of helical pile under three-dimensional condition,the result of which is compared with laboratory test. The outcome shows that the jacking-up displacement of helical pile with two small blades is the least when the frost depth reaches half the length of the pile. It indicates： the optimal type is picked through numerical simulation,which can provide a reference to the design of helical pile of photovoltaic stents in field test.