地下选厂硐室群开挖引起的围岩破裂特征

Characteristics of surrounding rock cracking induced by excavation on the underground mineral processing plant

针对张家湾地下选矿厂硐室群开挖引起的围岩损伤破裂问题,建立RFPA2D数值分析模型,模拟硐室群岩体内部的裂纹起裂、扩展的演化过程,探索阶梯形硐室群开挖卸荷引起的应力效应及其对围岩开裂的影响,并以声发射(AE)作为岩体瞬态卸荷开裂的依据,研究卸荷作用下硐室围岩的破裂范围。结果表明:硐室边墙最先出现起裂破坏,并逐渐沿着竖向发展;围岩裂纹沿着平行于最大主应力的方向发展;岩石非均质性对裂纹的延伸扩展影响很大,均质度越高,应力分布越集中,围岩破裂表现的脆性越强。

Aiming at the damage and fracture problems of surrounding rock mass during the excavation of Zhangjiawan underground mineral processing plant,the evolution rules of cracking initiation and propagation in rock mass are simulated after a RFPA 2D numerical analysis model established.And the stress effect induced by unloading condition and its influence on the surrounding rock cracking are explored.The scale of rock mass cracking caused by transient unloading is studied based on the criterion of acoustic emission(AE).The results show that the side wall of chamber first appeared initiation failure,and gradually develop along the vertical direction.The development direction of macro cracks is parallel to the maximum principal stress.And the homogeneity has a great influence on the crack extension and the higher the homogeneity,the more concentrated the stress distribution,the more brittle the fracture of the surrounding rock is.