Single Borehole Accident Analysis of North Three Entering Wind Shaft in Pingdingshan First Mine Built with High Strength Reinforced Concrete
WANG Hongju
Abstract：High strength reinforced concrete is used to shaft under freezing method construction, which belongs to mass concrete construction in low temperature environment. Therefore, its quality not only affected by the mass concrete casting, but also influenced by the mixing ratio and curing measures. Mainly embodied as follows:firstly, concrete strength development is badly influenced by the mix under low temperature environment;second?ly, concrete is not easily casted in situ and maintained in cryogenic environment;thirdly, lots of hydration heat is produced in mass concrete construction which will result larger temperature stress and shrinkage cracks;finally, free water in concrete is frosted which will cause expansion stress and cracks. Based on the shaft wall accident of north three entering wind well in Pingdingshan 1st mine built with high strength reinforced concrete, an engineer?ing and laboratory mix proportioning are compared and analyzed, also including antifreeze and curing conditions and hydration heat, crack resistance and frost heaving stress are calculated too, which shows the frost heaving stress is the direct cause of ring cracks, and unreasonable mixture and maintenance measures are central causes of the problem.
Keywords：wellborefreezing method constructionlarge mass high strength concretemixture ratiohydration heatfrost heaving stress
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 38-43 )