窄长型充填体的拱架效应及其对目标强度的影响

Arching effect of long-narrow cemented paste backfill body and its effect on target strength

利用Belem模型计算拱架效应对于充填体垂直应力的转化率,分析充填体3种应力状态下的目标强度(支撑围岩、侧向暴露自立、支撑设备),对比拱架效应引入前后充填体垂直应力降低比率。结果表明:谦比希铜矿窄长形充填体自重应力为0.4 MPa,拱架效应转化后,充填体所受垂直应力仅为0.055 MPa,转化率达到86.25%,最大主应力为充填体宽度方向上的水平应力0.289 MPa;支撑围岩与设备要求强度1 MPa,自立要求强度0.2 MPa。窄长型充填体的目标强度设计应考虑拱架效应对于垂直应力的转化,从而降低相关技术经济指标。

The vertical stress transformation by arching effect was calculated by Belem model, the vertical stress reduction ratio was compared before and after the introduction of arch, which from the analysis of three kinds of forces (surrounding rock supporting, self-standing with one face exposed, equipment supporting). The results show that, the self-weight pressure of long-narrow backfill body in Chambishi Copper Mine is 0.4 MPa, after the arching effect transporting, the remained vertical pressure is 0.055 MPa, which means almost 86.25% self-weight press is diverted to the horizontal pressure. The maximum principal stress is 0.289 MPa with the direction of horizontal along the width of backfill body. The required UCS the surrounding rock and equipment supporting is 1 MPa, for self-standing with one face exposed is 0.2 MPa. The target strength design of long-narrow backfill body should consider the arching effect on transformation of the vertical stress, so as to reduce the related technical and economic index.