自然崩落法拉底过程底部结构稳定性研究

Study on bottom structure stability in the undercutting process of block caving

自然崩落法技术要求高,涉及的岩石力学问题也非常复杂,不同拉底方式拉底过程中,底部出矿结构所受应力状态不同,稳定性也不同。以普朗铜矿相关条件为依据,采用数值模拟方法对自然崩落法开采拉底过程中底部结构的应力变化进行研究。分析研究表明:前进式拉底过程中,拉底推进线后方45m左右区域应力逐渐发生释放,最大主应力减小到10MPa左右,底部结构整体稳定性要好于后拉底,出矿水平最小主应力处于岩体抗拉强度范围内,且新增塑性区符合前进式拉底特点。因此,前进式拉底利于维护底部结构的稳定性。

Block caving technology has high technique requirements and the rock mechanics problems are complex.In the undercutting process different undercutting way causes different stress state and stability of bottom structure.Taking the conditions relative to Pulang Copper Mine as the basis,numerical simulation method was used to study the stress variation of bottom structure in the undercutting process of block caving mining.The results showed that in the process of advance undercutting,the stress released in the area behind the undercutting forward line 45 m,and the maximum principal stress reduced to 10 MPa,and the overall stability of bottom structure was better than using later undercutting.The minimum principal stress on ore drawing level was basically in the range of rock mass tensile strength,and the new plastic zone was according with the advance undercutting features.In this case,advance undercutting strategy is good for maintaining the stability of bottom structure.