动载作用下深部巷道围岩破坏特性和破裂区演化规律

    Damage characteristics of surrounding rock and evolution law of rupture zone in deep roadway under dynamic loading

    • 摘要: 随着煤矿开采深度的不断增加,因动力扰动产生的深部巷道工程灾害频发。为认清因动载作用引发的灾害作用机理,采用理论分析、数值模拟等研究方法,总结了深部巷道的动载特征,围绕应力波峰值和应力波延时2个影响围岩变形破坏的因素对深部巷道的围岩变形破坏特性进行了分析,并以朱集西煤矿工作面直接顶断裂引发冲击扰动为工程背景,对巷道的破裂区演化规律进行了模拟分析。结果表明:应力波峰值和应力波延时与围岩破坏的关系密切,随着冲击荷载峰值的增加,岩石试样的极限强度和峰值应变也会随之不断提高,但是极限强度的增速会逐渐放缓,岩石试样从下向上在内部逐渐形成“V”形剪切面,导致整体破坏;在荷载延时方面,随着荷载延时的增加,岩石的极限强度有增加的趋势,峰值应变影响较小,岩石试样的破坏呈现出从上向下的发育模式;随着应力波峰值的增大,巷道周边的拉伸破裂区范围和压剪破裂带范围不断增加;随着应力波延时的增加,拉伸破裂区范围逐渐减小,压剪破裂带范围逐渐增加。

       

      Abstract: With the continuous increase of mining depth in coal mines, the occurrence of deep roadway engineering disasters induced by dynamic disturbances has become more frequent. In order to recognize the mechanism of disasters caused by dynamic loads, we use research methods such as theoretical analysis and numerical simulation to summarize the characteristics of dynamic loads in deep roadways. The deformation and failure characteristics of surrounding rock in deep roadways are analyzed around the two factors affecting the deformation and failure of surrounding rock, namely the peak value of stress wave and the stress wave delay. Taking the impact disturbance caused by the direct roof fracture of Zhujixi Coal Mine working face as the engineering background, the evolution law of the fracture zone in the roadway is simulated and analyzed. The results indicate that there is a close relationship between peak stress wave and stress wave delay and the failure of surrounding rocks; as the peak impact load increases, the ultimate strength and peak strain of rock specimens also continuously increase, however, the rate of increase in ultimate strength gradually slows down, the rock specimens gradually form a “V”-shaped shear surface from bottom to top, leading to overall failure; in aspect of load delay, with the increase in load delay, there is a tendency for an increase in the ultimate strength of rocks, with little impact on peak strain, and the failure of rock specimens exhibits a development pattern from top to bottom; with the increase of peak stress wave, the range of tensile fracture zones and shear fracture zones around the roadway continuously expands; as the stress wave delay increases, the range of tensile fracture zones gradually decreases, while the range of shear fracture zones gradually increases.

       

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