磷矿地下开采地压规律的FLAC^(3D)数值模拟

FLAC^(3D) Numerical Analysis of Pressure Movement Laws of Underground Phosphate Mining

以云南磷化集团有限公司晋宁磷矿2号坑口北采区深部矿体为工程背景,通过FLAC3D数值计算工具,对不同矿体厚度下深部磷矿体地下开采过程中采场、围岩的稳定性及地压活动规律进行研究。数值计算结果表明:①矿体采出后,采空区上覆岩体的自重力向周边新的支承矿壁点转移,在采空区上方形成卸压带;同时在其前方与后方两侧矿壁附近形成支承压力增压带。随着采场向前推进,超前支承压力随之前移,采场覆岩受采动影响的范围也在不断扩大。②倾斜条件下,矿体开挖后所形成的采空区上部覆岩与下部覆岩应力状态是非均匀、非对称的,整体上采场上部矿压显现程度比下部明显。③随着开采矿层厚度的增加,矿体开挖形成采矿区后,采场覆岩受采动影响的范围更大,而矿压显现的程度则减弱。采空区前方支承压力区域最大应力集中系数减小,塑性区范围增大。

Taking deep ore-body of north mining area in Jinning phosphate No. 2 pithead of Yunnan phosphate group corporation as engineering background, the stability of stope roof and surrounding rock and mining pressure movementg laws for different thickness of phosphate ore during underground mining process of deep phosphate were studied with FLAC3D nu- merical simulation software. The numerical calculation results show that：①The weight of rock above the goal, transferred to the new supporting points around the goal. Then the distressed zone was formed which is located in the roof, and bearing pressure zone was located ahead of the goaf and both sides ore wall beside the goaf. With the advancing of the mining stope,the leading bearing pressure zone moved forward, and the affected areas by mining of the overlying strata is also ex- panded;②Under the inclination orebody,the stress state of the upper and lower part of the overlying strata above the goaf after excavating, were uneven and asymmetric, and the ground pressure in the upper part was more obviously then that in the lower part ;③With the increasing of the thickness of the seam, the areas affected by mining of the overlying strata became bigger after the mined-out area was formed, but the ground pressure appears weakening, stress concentration factor of the bearing pressure zone in front of the goaf and ground pressure became smaller. The maximum stress concentration of the bearing pressure zone in front of the goaf is decreased, and its plastic zone expanded.