Application Research Of Dynamic Cables In The Prevention And Control Of Rock Bursts

This paper introduces the features of rock burst hazard, and then analyzes thecharacteristics of deep coal mine roadway’s damage under the effect of rock burst. On thebasis of the prevention and control measures, I put forward my research methods andcontents.1. According to the similarity theory, we did the large geo-mechanics model test,considering it as plane strain. We put20g TNT in the inclined top of left hance to simulatethe rock burst. As for model material, we used the mixture of cement, sand and water by theproportion1:14:1.5, aluminium stick took the place of cables, and gypsum mortar took theplace of cement mortar. So we could see the complete process of rock burst under short andclose cables supported condition. The model test results show that the100mm short ofanchor cannot effectively prevent the destruction of the roadway, the rock mass near thewaist to explosion center is directly crushed out. The broken mass is mostly fragment, onlya little is big brick. From advanced buried strain gauge around the cavity, it is obvious thatthe dynamic strain field in the surrounding rock mass mainly is tensile strain. The strainmeasuring points closest to the explosion center are tensile damage; From the accelerationsensor advanced settled at the waist place of the arch, the acceleration near the explosioncenter of roadway mainly toward downside, while others mainly toward upside, and thepeak of downward acceleration is greater than the value of upward. With the increase ofdistance to explosion, the smaller of the peak acceleration value.2. On the basis of model test, I did the numerical simulation calculation through thefinite difference software FLAC3D. Back analysis the parameters of rock mass under rockburst and three orientation mechanical loading. In the numerical simulation calculation, Idesigned three supporting measures which contained: five kinds of cable length, two kindsof cable intervals and energy absorption device. Through above15kinds of workingconditions, I detail analysis the impact resistant characteristics. The results show that theretaining bolt length has the most reasonable length L. When actual supporting length is less than L, supporting effect enhance with the increase of the length; when actual supportinglength is bigger than L, supporting effect weakened with the increase of the length.Similarly, bolt’s interval has the most reasonable spacing D. The simulation of roadwaywalls’ surface energy absorption device indicates that the suction device cannot completelyprevent the destroy of roadway, but the degree of damage further reduce. Suction device caneffectively absorb part of the energy and assist the anchor-rock to take some impact pressure.From the stress state of anchors, we can see that the force of anchors is not uniform. Theanchors near the waist quickly bear tension and its value can nearly reach other bolts’100times.Although the three types of support measures didn’t reach its ideal effect, but thedegree of damage under different working conditions changed obviously. It can provide amore clear understanding of supporting about the rock burst, and it also provides thetheoretical and experimental basis for further studies in the future.