季冻区温度变化对基坑支护结构影响模拟分析

Simulation analysis on the influence of temperature change in seasonal frozen zone on foundation pit supporting structure

采用FLAC 3D有限差分软件对基坑悬臂桩支护在冻融循环作用下的影响进行模拟研究.建立基坑模型,采用摩尔-库仑弹塑性本构模型,讨论了正负温水平冻胀力和桩体水平位移的变化规律,以及不同温度冻结深度及冻结速率的变化.通过数值模拟结果表明温度对桩的水平冻胀力和水平位移影响很大,负温情况下温度越低,土体冻结速率越大,其水平冻胀力越大,桩体水平位移也随温度的降低而增大.水平冻胀力最大值在坑底处,水平位移最大值在桩顶处产生.土体冻融作用后,随温度的升高桩侧土压力值逐渐减小,水平位移也逐渐减小,且最大水平位移仍在桩顶.

FLAC 3D finite difference software isadopted to simulate the influence of foundation pit bracket pile support under freeze-thaw cycle.Based on the Mohr Coulomb elastic-plastic constitutive model,the variation of frost heaving force and horizontal displacement of pile in positive and negative temperature water level,and the change of freezing depth and the freezing rate at different temperatures is discussed.The numerical simulation outcomes show that the temperature has a great levelon the horizontal frost heave force and horizontal displacement of the pile.The lower the temperature is,the greater the freeze-up rate of the soil is,the greater the standard frost heaving force is,and the standard displacement of the pile increases with the decrease of temperature.The maximum value of level frost heaving force is at the bottom of the pit and the maximum value of level displacement occurs at the top of pile.After soil freezing-thawing,the soil pressure on the side of the pile decreases with the increase of temperature,and the horizontal displacement also decreases gradually,and the maximum horizontal displacement is still at the top of the pile.