Temperature Field Numerical Analysis of Different Freeze Pipe Spacing of Vertical Frozen Soil Wall Reinforcement at Shield Shaft

Abstract

Determining the freezing pipe spacing, the freezing reinforcement required range and method, acquiring the development and distribution patterns of frozen soil wall temperature field are the key issues needed to be addressed when using vertical freezing method for the soil reinforcement at shield shaft. Based on the shield launching project of the cross-river shield tunnel of Nanjing subway line 10 and the finite element numerical analysis software, the development and distribution patterns of different distance between freezing pipes of the vertical frozen wall are studied. The numerical simulation shows that, it is feasible to use the numerical model to simulate the temperature field of vertical frozen wall. Decreasing the distance between freezing pipes causes a greater impact on the temperature field. When freezing pipe spacing increases to 0.1m, frozen wall cross-lap time increases of about 1 day. With the freezing pipe spacing increasing, the cross-lap time increases linearly. The temperature of frozen wall decreases with the distance between freezing pipes decreasing, and the strength of frozen wall is more uniform. Results and conclusions form this research may play a useful role to aid designs of similar projects in future.