Study on Optimal Arrangement Method of Multi-circle Frozen Hole Under Action of Large Velocity Groundwater

Abstract

To solve the problem that the frozen wall formed by multi-circle freezing pipes is not easy to be closed under the action of groundwater with high flow rate, in view of the action characteristics of groundwater on the artificial freezing temperature field, it was proposed to optimize the design of the conventional freezing scheme by encrypting the freezing pipes at the upstream position of the water flow. The hydrothermal coupling mathematical model was constructed based on the apparent heat capacity method, and the rationality of the mathematical model was verified by large physical model tests. The mathematical model was used to analyze the effect of the freezing optimization scheme of a shaft in Huainan Mining Area. The results show: after encrypting the freezing pipes in the range of 120 degrees upstream of the outer ring of the double-loop pipes, compared with the conventional scheme, the closure time of the frozen wall at three flow rates was shortened by 7 d, 13 d and 57 d, respectively, when the groundwater flow rate was 10 m/d, 15 m/d, 20 m/d. And the thickness of the frozen wall was obviously increased corresponding to the same freezing time.

Keywords

• freezing shaft sinking
• hydro-thermal coupling
• optimization design
• numerical calculation
• frozen wall