工作面回采对断层裂隙带应力扰动规律及注浆加固机制研究

Study on the law of stress disturbance in fault fissure zones caused by mining face and the mechanism of grouting reinforcement

回采过程产生的超前支承应力是导致断层裂隙带发育、扩展、贯通的重要因素,而注浆是控制围岩稳定的重要手段,为分析应力扰动下注浆对断层裂隙带附近围岩加固效果,从应力对断层裂隙带围岩扰动规律和注浆加固机制两方面入手,借助相似材料模拟试验得出围岩垮落情况、位移变化数据、应力变化数据与数值模拟结果损伤云图、剪切应力曲线图等参数结合手段,分析工作面回采过程对断层裂隙带应力扰动规律及注浆加固机制。结果表明:回采产生的超前支承应力扰动随工作面推进是动态演化过程,该应力会诱发断层裂隙带的发育、扩展,距离工作面位置越近断层裂隙带的应力值越大,并且断层裂隙带端部应力集中现象明显;随着工作面的开挖面与断层构造面距离减小,超前支承应力扰动使断层裂隙带损伤呈不均匀性分布,沿着断层面和煤层顶板处的岩层受采动应力影响要大于底板岩层,离煤层越近的岩体受到应力扰动越明显;通过对比注浆后和未注浆时的围岩、断层裂隙带应力变化得出,注浆使断层更加稳固,上下盘黏结更加紧密,减弱了断层对应力的阻隔效应,减小了断层软弱、破碎、阻碍采动应力传播的特点,有效抑制断层裂隙带发育、扩展,使断层不易活化从而降低了断层滑移趋势。

The advanced support pressure produced in the mining process is an important factor leading to the development,expansion and penetration of fault fracture zones.Grouting is an important means to control the stability of surrounding rock.In order to analyze the reinforcement effect of grouting on surrounding rock near fault fissure zones under stress disturbance,disturbance rule of surrounding rock in fault fissure zones under stress disturbance and reinforcement mechanism of grouting were studied in this paper,by using similar material simulation tests to obtain surrounding rock collapse,displacement change data and stress change data,and numerical simulation tests to obtain damage nephogram,shear stress curve and other parameters.The results show that the advanced support pressure disturbance caused by mining is a dynamic evolution process as the working face advances.This stress can induce the development and expansion of fault fracture zones,and the stress value of the fault fracture zone increases as it is closer to the working face location and the stress concentration at the end of the fault fracture zone is obvious.As the distance between the excavation surface of the working face and the fault structural surface decreases,the disturbance of advanced support pressure causes uneven distribution of damage in fault fracture zones;Grouting makes the fault more stable and results in the hanging and foot walls more tightly bonded,reducing the barrier effect of the fault on stress.Grouting effectively inhibits the development and expansion trend of fault fracture zones,making them difficult to activate,thereby reducing the trend of fault slip.