Study on Site Measurement of Floor Heave Occurred in Mine Freezing Shaft Sinking in Soft Rock of Western China

JIANG Guo-jing; LI Ai-min; NIU Qing-he; GUO Deng

doi:10.3969/j.issn.1002-6029.2014.04.010

Abstract：A mine main shaft of Dahaize Mine had a net diameter of 9.6m and a shaft depth of 701.96m. The mine shaft was construction with a full depth freezing method ,a designed freezing depth of the mine shaft was 718m and the mine shaft was a mine freezing shaft in soft rock in Western Chi-na. When the mine shaft was excavated at a depth of 575m ,a site study was conducted on the floor heave of the shaft sinking face. A lithology at the depth exposed of the mine shaft was siltstone and the bottom of the siltstone would be mudstone as predicted. The site measurement showed that a floor heave value was not high ,there was a phenomenon that the floor heave was steadily increased from the mine shaft liner to the mine shaft center ,a max floor heave value was only 20mm ,an average floor heave speed was 1.76mm/day and was obviously lower than the floor heave speed of 15~30mm/day at a freezing section in clay layer of Easter China. T hus the floor heave could show that an advance dis-placement of the freezing wall was small ,a stability of the freezing wall was high and the excavation and lining construction were safe. A max floor heave value was occurred at the west side of the mine shaft and a min floor heave value was occurred at the east side of the mine shaft. This showed different positions ,the stability of the shaft freezing wall showed uneven features. The site study on the floor heave in the mine shaft could provide references to the design and construction of the mine freezing shaft in the soft rock of Western China.