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随着城市地铁规模的不断发展,冻结法在地铁联络通道施工中得到了广泛应用.为了得到合适的地层冻结工艺参数和指标,了解开挖隧道对地层稳定性的影响,保证工程的安全性,基于考虑相变及冻胀的热-流-固(THM)耦合理论,采用COMSOL有限元分析软件模拟某地铁联络通道水平人工冻结及开挖施工过程.分析了冻结过程中地层温度场、渗流场及位移场的变化规律,研究了开挖后地层位移场的分布规律.结果表明:由于水渗流作用,温度场和位移场的分布不再关于y轴对称;在人工冻结过程中,地表处冻胀位移的最大值出现在y轴以右,冻胀量变化表现为先线性增长,而后趋于稳定.总体上,实施人工冻结可以很好地增加周围土体的强度及稳定性,对止水和抑制地层变形具有良好的效果.
With the continuous development of urban subway scale, the freezing method has been widely used in the construction of subway contact channel.In order to get the appropriate parameters and indicators of formation freezing process, the influence of excavation tunnel on the stability of the formation, to ensure the safety of the project, Based on the thermo-fluid-solid (THM) coupling theory, which takes into account the phase transition and frost heave, COMSOL finite element analysis software was used to simulate the horizontal artificial freezing and excavation construction process of a metro communication channel.The formation temperature field, seepage field And the displacement field, the distribution law of the displacement field after excavation is studied.The results show that the distribution of the temperature field and the displacement field is no longer symmetrical about the y-axis due to water seepage. During the artificial freezing process, The maximum value of expansion displacement appears to the right of the y-axis, and the change of frost heaving amount shows a linear increase first and then tends to be stable.Overall, the artificial freezing can well increase the strength and stability of surrounding soil, And inhibit formation deformation with good results.