Deep Freeze Wellbore Large Volume Of High-strength Concrete Preparation And Crack Control Study

During the recent years, in order to settle the problem of energy's scarcity, a wave of new mines' constructing has been starting in the north and the middle part of Anhui Province. The ongoing exploitation of energy source is deep-level source, and the alluvium through which the shafts drill is also deep. Therefore, in order to minish the thickness of shaft lining and advance the wear of shaft lining's concrete, high-strength and high-performance concrete (HSAHPC) is adopted to construct the shaft linings which are dug through freezing method.For HSAHPC is adopted to shaft linings in operating condition of frozen and thick surface soils for the first time. So in the thesis, experimentation research is done for shaft lining's HSAHPC firstly. In the precondition of using superplasticizer, then through the approach of triple-mixed mineral additions—silica fume, milled slag and fly ash, the concrete not only fufil the request of concrete's properties of high strength and early strength, but also advance concrete's late strength and durability. Secondly, because of the shaft lining's concrete has the characteristics of bulky volume, hydrating rapidly, high temperature rising of hydration heat and great grad of temperature falling, which are easy to lead to cracking of concrete. So, in order to control the concrete's cracking effectively, the author studied the hydration regularity of shaft lining's concrete, the change and distributing regularity of concrete's temperature and stress through the methods of field monitoring, model test and numerical simulation. At last, the thesis put forward the cracking control's technical measures, which will offer the basis of design and reference for following applying HSAHPC to shaft linings in operating condition of frozen and thick surface soils.