Optimization of three-circle pipe layout for freezing shaft sinking based on combined weighting-grey correlation method

Abstract

Aiming at the problem of multi-loop pipe layout design of extra-thick alluvial layer freezing method, taking the second auxiliary shaft freezing project of Dingji Coal Mine in Huainan and Huaibei Mining Area as the background, the three-loop pipe freezing scheme is optimized based on combination weighting theory and grey correlation degree method. According to the engineering geological conditions and the design principle of freezing shaft sinking, the corresponding freezing temperature field analysis model is constructed by ANSYS numerical analysis software. Based on the combination weighting-grey correlation method, the orthogonal analysis method is used to study the influence of outer row hole, middle row hole diameter and hole spacing on the temperature field of frozen wall. The results show that the outer hole circle diameter and hole spacing have great influence on the well side temperature, frozen wall thickness and average temperature of frozen wall. Combined with the construction characteristics of the freezing pipe, the optimal layout scheme of the three-ring freezing pipe is determined as follows: the diameter of the middle row hole circle is 23.5 m, and the hole spacing is 1.34 m; the diameter of the outer hole circle is 31.2 m, and the hole spacing is 1.75 m; the predicted value of numerical analysis is consistent with the field monitoring results, which proves the rationality of the numerical analysis model.

Keywords

• tricycle tube freeze
• scheme optimization
• combination weighting
• grey correlation method
• numerical simulation