金属矿山崩落法开采顶板围岩崩落机理与塌陷规律

以湖北程潮铁矿西区开采为工程背景,首先结合2个钻孔实时监测的顶板围岩崩落曲线、矿体赋存条件、地层结构和钻孔岩芯资料,揭示顶板围岩崩落过程的基本特点和机理。其次建立了103个沉降点和55个水平位移点的地表塌陷监测系统,通过对15个月观测资料,特别是对沉降量、沉降速率和水平位移量与时间曲线的关系,以及沉降漏斗发展过程剖面图分析,总结出西区地表变形的量值特征和一般规律。初步揭示了金属矿山无底柱分段崩落法开采过程中,顶板围岩崩落机理和地表沉陷的基本规律。

Research on Caving Mechanism of Surrounding Rock and Rule of Surface Subsidence Due to Pillarless Sub-level Caving Method in an Iron Mine

The rock mass failure due to pillarless sub-level caving method in metal mines occurs as two stages: caving of roof surrounding rock, surface subsidence and deformation. This paper presents a case study and gives a detailed discussion on how to predict the caving process and the subsidence range in the western region of Chengchao iron mine. First, analysis on monitoring datas (such as the caving curved line of roof surrounding rock, accumulating conditions of the ore body, stratigraphic configuration and drill core dates.) of two drill-holes was made to show the fundamental features and principles of the caving process. Then, an observation system for surface subsidence was built based on 103 settlement observation points and 55 horizontal displacement points. Observational datas of 15 months, especially relation curves between the settling amount, the settlement rate, the horizontal displacement and the time, the developing process of settlement crater were analyzed to show the magnitude characteristics and general principles of the surface deformation. The research findings provide the theoretical basis to predict the subsidence range and prevent surface deformation for Chengchao iron mine.