An Experimental Evaluation of the Weathering Effects on Mine Shaft Lining Materials

Abstract

Many shaft collapses are related to the deterioration and failure of the masonry shaft lining materials. In modern mine shaft, concrete is widely used to provide support. To analyse shafts stability, the properties of the lining need to be well defined. The behaviour of masonry and concrete can be considerably affected by long-term exposure to harsh mine water. This paper presents a study which focuses on the weathering effects of mine water on lining materials (brick, mortar, and concrete). To reproduce the weathering process, samples were placed into solutions of potable water, artificial mine water, and a more aggressive mine-water solution for just less than one year. Four phases of laboratory tests were conducted throughout the time period to assess the degradation of mechanical properties of the lining materials. Particular attention is given to the degradation of material strength and stiffness. Results indicate that the harsh acidic mine water has pronounced detrimental effects on the strength and stiffness of mortar. The weathering process is shown to have the most significant effect on the stiffness of concrete and mortar. It is also shown that the use of mass loss as an index for evaluation of mechanical properties may not be appropriate.

Preliminary assessment of the efficacy of nano–MgO–based dispersion for the consolidation of artificial weathered sandstone

“…The conservation materials can be applied only when they had been confirmed to be effective and harmless to the stone matrix, according to the principles of the conservation of heritage sites in China (ICOMOS, 2002). On the other hand, because of the diversity of natural weathering factors, the physical‐mechanical properties of weathered sandstones in different positions varied (Yang et al, 2017); therefore, the naturally weathered sandstones with sufficient quantity and constant characteristics are rarely available (Franzoni et al, 2013). In addition, during the preparation process of specimens, it was difficult to cut the naturally weathered sample into an ideal cube shape due to the shedding of sand grains.…”

Vertical Shaft Support Improvement Studies by Strata Grouting at Aquifer Zone

“…While the vertical stress increases gradually to its limitation, the shaft lining cannot resist the force and then fails. e failure mostly occurred near the interface between aquifer and bedrock, sometimes in the alluvium a few meters above the bedrock [14][15][16][17]. Many results of shaft lining destructive tests and the data of in situ experiment conducted in mining areas of Huaibei, Xuzhou, and so on, confirmed the existence of vertical additional force and its influence on the shaft lining failures [18][19][20].…”