Selective Tests of Grouting Material for Fractured Coal and Rock Masses in a Water-borne HS Environment
Coal mining is vulnerable to multiple kinds of threat from water incursion. Many coal seams contain dissolved H2S, which may be released during mining, seriously endangering the health of workers. Orthogonal testing was used to analyze the physical and mechanical properties of composite slurries in different proportions. The results showed slurry with a water-solid ratio of 0.8:1 to have the optimal combination of properties. A uniform experimental method was used to investigate the impact of the water-cement ratio, concentration of sodium silicate, and volume of cement-sodium silicate (CS) on the setting time and consolidating strength of CS slurry. This paper provides the appropriate application scope of two grouting materials (optimized composite slurry and CS slurry), based on experimental data and the results of a large number of in situ trials. Finally, the optimized composite slurry and cement-sodium silicate slurry were used to carry out grouting of the center auxiliary transport roadway of the 3 coal seam at the Ningtiaota Coal Mine, operated by the Shaanxi Coal Industry Group. It was shown that the type and formula of the slurry could be changed in a timely manner, based on the water outlet and concentration of H2S at the site, achieving successful grouting reinforcement and seepage-proofing.
Mechanical properties of soilcrete mixtures modified with metakaolin
Abstract The present article discusses the synthesis of soilcrete mixes with the addition of metakaolin as a mineral admixture for their potential utilization in civil engineering, either as grouts in soil applications (especially in corrosive environments such as coastal regions) or as a material that can be used for the construction of structural elements (i.e. piles). Soilcrete mix design optimization and mechanical behaviour of the produced samples have been experimentally investigated. It has been found that the beneficial properties of metakaolin may be used in producing soilcrete mixes with improved mechanical properties, which, provisionally, can be used as a structural material.
Philip Roth’s Great Books: A Reading of The Human Stain
Philip Roth belongs to the first generation of American novelists for whom a university education in the liberal arts was the norm. This essay charts Roth’s developing acquaintance with classical literature, the starting point for Great Books courses in the 1950s, and the implications for his fiction of his understanding of the difference in scope and purpose between the two representative classical genres. It focuses on The Human Stain (2000), the novel in which he reflects most directly upon what tragedy and epic once did, and what might happen to novels if they became more like the one or the other.