Analysis on The Influence Factor of Low-Strength Wet Shotcrete in Frigid Mining Area

摘要

Wet shotcrete technology is being gradually used in roadway support in frigid mining areas. Thus,problems such as low strength, fragility, and high repair rate have also emerged. This study focuses on lowstrength, cracking, and other problems in the wet shotcrete support of a mine. It introduced the fishbonediagram to investigate the effects of temperature, cement content, and water-cement ratio (W/C) on thestrength of the shotcrete layer. The microscopic morphology of wet shotcrete based on scanning electronmicroscopy (SEM) is observed. Results demonstrated that temperature was the main influencing factor ofwet shotcrete in frigid mining areas. When the curing temperature was lower than 10°C, the early strengthof wet shotcrete dropped significantly. Temperatures above 15°C were favorable for later gain in strength.W/C was of a complementary relationship with strength development at different ages. Temperature wasthe essential factor that influenced the microscopic morphology of wet shotcrete. Furthermore, internalinitial porosity and aggregate interface bonding strength had a direct effect on macro-mechanical pro-perties of wet shotcrete.