|
With the continuous and steady development of China 's social and economic , the the city metro construction has also become one of the most important part . Level of artificial ground freezing method construction as a modern construction methods , due to the unique advantage of having more and more favored by the engineering community . However , freezing construction method of surface frost heave and thaw impact , and is not to be ignored . This paper studies the freezing construction method of surface thaw role . In this article , do not freeze the soil temperature field directly will freeze the the completely thawed soil volume change as displacement load applied to the walls of the freeze out of the loop , and then calculate the surface thaw displacement . With large engineering calculation software ANSYS, establish a reasonable calculation model , artificial level SimCity Metro freezing construction method , the construction soil mechanics parameters , design freeze wall thickness, tunnel depth and excavation radius parameter changes , freeze the circle completely thawed after the surface thaw displacement impact . According to the results , summarized the surface thaw displacement parameters under variation on the various parameters on the the surface thaw displacement sensitivity analysis . Further analysis of existing upper load , the size of the load values ??and loading position on the surface melt impact of Shen displacement . Through numerical experiments , the following main conclusions : the impact of various parameters on the the surface thaw displacement of descending order : excavation radius , tunnel depth , soil deformation modulus freeze the wall thickness , soil cohesion and the angle of internal friction ; 2. surface thaw displacement , the vertical displacement of the major thaw displacement . In the analysis of the impact of soil mechanics parameters , the modulus of deformation of surface vertical to thaw displacement affect the most, when the deformation modulus is reduced by 5 % , the 2.1% increase in the maximum vertical displacement ; When the deformation modulus is reduced by 10 %, the maximum vertical displacement of an increase of 4.4% ; made ??in this article assume that the model under the premise of the tunnel suitable for freeze wall thickness of 1.2m -2.0m , the excavation radius 4m- 5m . 4. Surface in comparison with the overlying loads thaw displacement curve , it can be seen , the vertical to the displacement curves gradually from the asymmetry becomes symmetric , which shows that the greater the distance of the level of the axis of the upper edge of the building foundation from the hole , the building less effect on the the surface thaw displacement of .
|