ABSTRACT:

Based on the theory of three-dimensional elastic-plastic seepage, the prediction of sandstone displacement and stress distribution law of the shaft frozen wall in Xiaozhuang Coal Mine was calculated. The prediction of sandstone displacement of frozen wall is performed by FEM numerical calculation. The results indicate that the biggest radial displacement was 2.036 × 10−3m when the thickness of frozen wall and roadway height were 2.5 m and 4 m, respectively, which could meet the requirements of safety regulations that the radial displacement should not exceed 50 mm and would not cause damage to the frozen pipe. The result showed that the design of frozen wall thickness and roadway height was proper, which can ensure the construction smooth. The actual monitoring data were basically consistent with predictive value. The study shows that FEM calculation could well predicate the radial displacement of frozen wall, and it is a quilt effective way of research to predicate stability of surrounding rock.

1 INTRODUCTION

Freezing method is the main construction method which can make sure the wellbore across the unstable alluvium and weathering zone of bedrock and nearby the upper aquifer (Chen et al. 2000, Cui et al. 1998), freezing method construction can guarantee the working face anhydrous (Cui 2008). Frozen design must be aiming at the buried characteristics of alluvium and frozen rock mechanics characteristics, to meet the strength of the frozen wall, the deformation and water plugging requirements. At present the main problem of the freezing method construction is the frozen wall displacement is too large which leads to the broken of freezing pipe. Freezing method in general can be divided into the whole deep freezing method and the partial deep freezing method (Yao et al. 2005). Partial deep freezing method construction can avoid the damage, which the in-gate construction can easily produce the annular water channel by the frozen pipe and temperature tube, and the damage caused by the cavern rock (Zhao et al. 2012), and now non whole deep freezing method construction is been widely noticed (Yang et al. 2012). Xiaozhuang coal mine is the first to use the partial deep freezing method construction in northwest. In this paper, based on Xiaozhuang Coal Mine construction, research on the partial deep freezing method construction is carry out. By using of FEM software ABAQUS, following the process of the partial deep freezing method construction, the displacement law of the frozen wall, combined with the actual testing data analyze the stability of surrounding rock of the shaft frozen wall in rich water sandstone is analysed. The reasonable parameters for stability of surrounding rock of the shaft frozen wall in rich water sandstone formation is provided.

This content is only available via PDF.
You can access this article if you purchase or spend a download.