Numerical Simulation Of Frost Heave In Subway Construction By Artificial Freezing Method

As China socioeconomic sustained steadily development, urban subway construction also become one important part. Artificial ground horizontal freezing Method Construction as a modernization construction method, due its unique superiority gaining engineering favor. However, using freezing method construction on surface frost heave and thaw impact also not we neglected.This paper study adopts freezing method construction on surface thaw role. In this article, not establish freeze soil temperature field, directly freeze soil completely defrosted volume change as displacement load, impose in freeze outsiders wall then calculated surface thaw displacement. With large engineering calculation software ANSYS, establish reasonable calculation model SimCity subway artificial horizontal frozen construction, construction soil mechanical parameters design freezing wall thickness, tunnels Depth and excavation radius parameters changes, freeze circle completely defrosted surface thaw Displacement. According calculation results, summarized surface thawing displacement in each parameter under changing law and parameters on surface thaw displacement sensitivity analyzed. Further analysis exist upper loads, load value size and loads Position on surface thaw Displacement.By numerical test get following main Conclusion:1. Various parameters on surface thaw Displacement decreasing order:excavation radius, tunnel depth, soil deformation modulus, freezing wall thickness, soil cohesion and internal friction angle;2. Surface thaw displacement in vertical displacement mainly thaw displacement. Analysis soil Mechanical Parameters impacts deformation modulus on surface vertical to thaw displacement greatest impact, when deformation modulus drops 5% maximum vertical to displacement adds 2.1%; when deformation modulus drops 10%, the maximum vertical to displacement adds 4.4%;3. In this paper, the assumptions made and the established model under the premise of the freezing tunnel wall thickness suitable for the 1.2m-2.0m, excavation radius of 4m-5m;4. Contrast with the overlying load when the thawing surface displacement curve, we can see, the vertical displacement curve gradually becomes symmetric from the asymmetric, indicating the basis of the upper edge of the building away from the hole axis of the larger buildings thawing on the surface of the smaller displacement.