Experimental Study On Mechanical Properties Of Sidewall Concrete Under High-Pressure Water Load

With the shallow coal resources exhausted, in order to ensure the sustainable development of coal industry, we need to develop the deep coal resources. Currently, some bore's depth has reached 1,000 meters, but the shaft will pass through deep alluvium during the construction of new wells in the Huang-huai region. The deeper the shafts, the higher the water-pressure imposed on the shaft lining, which brings the safety problem. So it is necessary to study the mechanical properties of wall concrete at the high water -pressure.It points that the high-pressure water load will be directly on the shaft after the frozen wall thawing, by the analysis of the actual stress state of frozen wall of deep alluvium. Thus the concrete mechanical properties should be considered under direct high-pressure water load.In the experimental research, sealed and unsealed concrete specimens with 100mm×100mm×100mm cube specimens were imposed loads on by the hydraulic loading device in the institute of underground structures of Anhui University of Science and Engineering, by the ways of different water loads with 0,3MPa and 5MPa. In order to analyze the influence of strength grade of concrete on compressive strength of concrete, we respectively use C50, C60 and C70 concrete standard specimens at the confining pressure of 0,3Mpa and 5MPa, the compressive strength of standard concrete specimens are respectively C50, C60 and C70. The results showed that the compressive strength of concrete evidently increased as increasing of confining pressure when the samples are sealed, it respectively increased 27.8%and 57.2% under 3MPa and 5Mpa confining pressure. And the compressive strength were increased less with the increasing of standard strength grade, also when the samples are not sealed.In theoretical aspect, the initiation and growth of cracking in the wall concrete in the effect of hydraulic fracture was studied the damage mechanism of concrete under the high-pressure water load was also analyzed. Thus we have further understanding of the failure mechanism of wall concrete. The experimental data is good for the calculation of strength of wall concrete in the high-pressure water load.