基于不同开采方式的煤岩采动力学特性实验研究

Experimental Research on Mining-induced Mechanical Behavior of Coal Based on Different Mining Layouts

随着煤炭资源的深部开采,由深部复杂应力环境和开采扰动引发的岩爆、围岩大变形等地质灾害问题愈发频繁,亟需系统性探究不同初始环境下煤岩常用开采方式的采动力学行为及能量演化特征。为此,该文设计了不同开采方式采动试验路径,在常规三轴试验仪器上实现了煤岩不同开采方式的采动力学试验,从而揭示了煤岩不同开采方式下采动力学行为及能量演化特征。实验表明,相比常规三轴压缩变形特性,煤岩在采动条件下仅产生少量的体积压缩,扩容现象更早产生也更加显著;按照保护层开采、放顶煤开采和无煤柱开采的顺序,煤岩采动变形逐渐增大,煤岩采动破坏模式从张拉剪切破坏向单纯的剪切破坏发展变化,逐渐趋向于三轴压剪破坏形式,伴随的能量数值也越大,采动影响更加剧烈;随深度的增加,煤岩开采中伴随的能量增加,采动破损程度逐渐增大,煤岩开采的安全稳定性问题随之突出,开采难度也随之提高。这些实验研究结果为煤炭资源的安全高效开采提供了一定借鉴和指导。

With the deep mining of coal resources,geological disasters such as rock burst and large deformation of surrounding rock caused by deep complex stress environment and mining disturbance become more and more frequent.It is urgent to systematically explore mining-induced mechanical behavior and energy evolution characteristics of coal under three typical mining layouts.Therefore,the mining stress paths of different mining layouts was designed in the test,the mining simulation test of coal under different mining layouts was realized using the conventional triaxial test instrument,and the mining-induced mechanical behavior and energy evolution characteristics of coal under different mining layouts were revealed.The experimental results show that,compared with coal deformation characteristics of conventional triaxial compression,a few volume compression existed under mining conditions,and the dilatancy phenomenon occured earlier and more significantly.According to the sequence of protected coal seam mining,top-coal caving and non-pillar mining,the mining deformation of coal gradually increased,coal mining failure mode changed from tension shear failure to pure shear failure,finally tended to triaxial compression shear failure.Accompanying energy was larger,and mining impact was more severe.With the increasing depth,the accompanying energy in coal during mining increased,the degree of mining damage gradually increased,the safety and stability problem of coal under mining became prominent,and the mining difficulty also increased.These experimental results provided references and guidances for the safe and efficient mining of coal resources.