Study on the rapid construction method of large section vertical well in thick alluvium

Abstract

ABSTRACT The rapid construction of a shaft is very important for shortening the shaft construction period and improving the mine economic benefits. In addition to the effects of hydrogeological conditions, the shaft construction speed also affects the selection of operation mode and the rationality of mechanical equipment. Considering the specific geological conditions of thick alluvium and large aquifers on the surface of auxiliary shaft in Fucheng mine, the main factors which affect the construction speed of the large-section vertical shaft in the thick alluvium are analyzed in this study. Based on the field investigations and hydrogeological conditions of the auxiliary shaft, the freezing method is determined as a rapid construction scheme for the auxiliary shaft as well as designing the arrangement of freezing holes and optimization of freezing parameters. The dynamic adjustment of freezing parameters is identified by studying the information provided by freezing construction technology. After shaft excavation, the deformation of the shaft lining in the alluvium section of topsoil is analyzed. It is concluded that the deformation of the shaft lining increases with the depth of the topsoil layer, however, the maximum deformation is within the allowable range of design. The short section excavation and masonry mixed operation mode is selected, and “five major and one deep” rapid mechanized operation lines are matched. The scientific operation cycle chart is compiled. And operation results fulfilled the actual needs. These results will provide guidance and reference significance for mine construction under similar geological conditions.