结构面对程潮铁矿西区地表变形的影响分析

以程潮铁矿西区为例,通过对现场结构面和裂缝分布特征的调查,以及结合地表变形监测数据的分析,揭示了矿区结构面对地表变形的影响。研究结果表明,在矿区较大的水平应力条件下,岩体结构面改变了地表拉伸变形分布和破坏形态,加剧了岩体变形,在ⅰ区(剖面Ⅲ以东区域),目前最外侧裂缝以内的岩体沿着NNW结构面发生倾倒滑移破坏,地表变形以快速变形为主,而最外侧裂缝以外的岩体沿着NNW结构面发生弯曲变形,地表变形以线性稳定增长为主,进入了倾倒破坏阶段,该区域的岩体主要发生水平位移;在ⅱ区(剖面Ⅲ以西区域),岩体在开采沉陷引起的南北向应力作用下,分离成平行的块体,地表变形以快速变形为主,在局部区域,产生的一部分平行块体在近东西向的应力作用下,沿着NNW结构面产生倾倒破坏。所得成果对类似金属矿山的地表征地及安全高效生产具有实际指导意义。

Analysis of influence of structural planes on surface deformation in western area of Chengchao Iron Mine

Based on a survey of the distribution of in situ structural planes and surface cracks and an analysis of surface deformation monitoring data, a case study is performed in Chengchao Iron Mine to investigate the influence of the structural planes on the surface deformation in the mining zone. The results show that, under a large horizontal stress condition, the structural planes of rock mass can change the surface tensile deformation distribution and the failure pattern, and intensify the deformation of rock mass. In areaⅰ(i.e., the area on the eastern of section Ⅲ), the toppling-sliding deformation is formed along NNW structural planes within the outermost crack, and the surface deformation is featured mainly with rapid deformation; the bedding deformation occurs along NNW structural planes outside the outermost crack, and a linearly stable development of surface deformation prevails; In the stage of toppling failure, the deformation in this area is mainly dominated by horizontal displacement of rock mass. In areaⅱ(i.e. the area on the western of section Ⅲ), under the north-south horizontal stresses caused by mining subsidence, the rock masses are separated into parallel blocks, resulting in rapid surface deformation. In some local regions, some parallel blocks mentioned above fails in a toppling way along NNW structure planes under the west-east horizontal stresses.