冬季深基坑水平冻胀力试验研究

Experimental Study on Horizontal Frost Heave Force of Deep Foundation Pit

依托呼和浩特市某地铁车站基坑工程,通过室内模型试验和数值模拟分析,结合呼和浩特市气候条件,模拟极端降温过程,分析研究深基坑的土体温度变化分布特征、水平冻胀应力分布规律以及冻胀引起土体及支护结构的变形规律。研究表明:外侧土体温度变化梯度大,内部土体温度相对稳定且变化相对滞后,基坑最大冻深可达到1.1~1.2 m;随基坑深度的增加,水平冻胀力先增大后减小,呈抛物线分布模式,最大值出现在深度约8~10 m处;极端气候条件下,基坑最大水平冻胀力达120~140 kN,对基坑支护的设计与施工产生不可忽视的影响,为严寒地区深基坑工程提供借鉴和参考。

Based on the foundation pit of a subway station in Hohhot City,the extreme cooling process was simulated accord-ing to the local climate conditions.Through indoor model experiments and numerical simulation,the distribution characteristics of soil temperature,frost heaving stress and the deformation law of soil and diaphragm wall under the action of freeze-thaw cycle were stud-ied.The results show that:the outer soil temperature gradient is large,and the internal soil temperature is relatively stable and the change is relatively lag,with maximum freezing depth of the foundation pit being 1.1~1.2 m;the horizontal frost heaving force in-creases at first and then decreases with the depth of the foundation pit,showing a parabola distribution pattern,and the maximum value appears at the depth of about 8~10 m;under the extreme climate conditions,the maximum horizontal frost heaving force reaches 120~140 kN.It has a great influence on the design and construction,and provides reference for deep foundation pit engineering in severe cold area.