Abstract
In the freezing method, frozen soil wall to endure earth pressure and hydraulic pressure is made by installing freezing pipes near the underground constructions such as shaft. After creating the frozen soil wall, a partial temperature rise or thawing of the frozen soil may occur due to the heat of excavation or of gas cutting of steel. In addition, the suspension of circulation of coolant to the freezing pipes or the change of temperature may take place in order to control the creation of the frozen soil wall.
In general, the shape of the frozen soil wall created by this method is complicated, and because heat conditions change with time, it is important to predict in advance things like the range of frozen area and temperature distribution over time. Consequently, we introduce three-dimensional nonsteady heat conduction analysis based on differential equations, and explain the differential equations and boundary conditions in this paper. We confirm the validity of this method by the comparison with the measured values of the construction site and the analytic values.
Also we present the results of model analysis envisioning the underground connection of shield tunnels in order to evaluate the effect of heat transfer on a frozen soil wall.
