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古建筑压煤开采对斜坡上覆堆积层变形扰动影响研究

Study on influence of coal mining under ancient building on deformation disturbance of overlying accumulation layer on slope

  • 摘要: 针对缓倾顺层斜坡上覆堆积层的采动稳定性与变形机理的研究,特别是从协调地下资源开采与地上文物古建筑安全防护视角出发的研究处在探索阶段。以山西省宝应寺斜坡堆积层为研究对象,基于地表动态监测与地质过程机制分析,结合数值模拟研究了堆积层稳定性与地表裂缝成因机制,并探讨优化了开采方式。研究表明:①长壁式地下开采是引起堆积层变形的诱因,堆积层软弱特性与斜坡软硬互层结构是其变形内因。堆积层下伏基岩变形模式为垂向挤压水平拉张,对堆积层变形具有放大效果,牵动其产生地裂缝。堆积层变形破坏机制为:坡下采空—覆岩弯曲—侧岩倾倒变形—下伏岩层应力集中—牵动拉裂;②堆积层裂缝分布在上坡方向采空区工作面端部附近,平面上近似平行,呈“之”字或锯齿状。地物裂缝较之地表裂缝数量更多、但规模更小,寺院建筑群受隐伏张性地裂缝影响致地基形变造成地面以上结构开裂;停采后监测期内,堆积体变形速率趋于收敛,残余变形消减,由变形移动转为基本稳定;③完全采空后,堆积层表现为以下错为主的拉张变形,剪应变显现,持续开采条件下堆积层变形程度将加剧。下伏基岩最大主应力增量达1080.75%,拉应力集中;④短壁房式开采留设区段煤柱利于减小堆积层变形。研究为认识地下资源开采扰动斜坡上覆堆积层变形破坏与寻求古建筑压煤开采文物保护解决方案提供了参考。

     

    Abstract: The research on the mining stability and deformation mechanism of the overlying accumulation layer on the gently inclined bedding slope, especially from the perspective of coordinating the exploitation of underground resources and the safety protection of ancient buildings on the ground is in the exploratory stage. Taking the accumulation layer of Baoyingsi slope in Shanxi Province as the research object, based on the analysis of surface dynamic monitoring and geological process mechanism, combined with numerical simulation, the stability of accumulation layer and the formation mechanism of surface cracks were studied, and the mining method was discussed and optimized. The research shows that: ① Long-wall underground mining is the cause of the deformation of the accumulation layer, and the weak characteristics of the accumulation layer and the soft and hard interbedded structure of the slope are the internal causes of its deformation. The deformation mode of the bedrock under the accumulation layer is vertical extrusion and horizontal tension, which has an amplification effect on the deformation of the accumulation layer and affects the generation of ground cracks. The deformation and failure mechanism of the accumulation layer is as follows: mining under the slope-bending of overburden rock-toppling deformation of side rock-stress concentration of underlying rock-pulling and cracking; ② The cracks in the accumulation layer are distributed near the end of the working face of the goaf in the uphill direction, and are approximately parallel on the plane, showing a zigzagging motion or serrated shape. The number of ground fissures is more than that of surface fissures, but the scale is smaller. The temple buildings are affected by the hidden tensile ground fissures, which cause the deformation of the foundation and cause the cracking of the above-ground structure. During the monitoring period after stopping mining, the deformation rate of the accumulation body tends to converge, the residual deformation is reduced, and the deformation movement is basically stable. ③ After complete mining, the accumulation layer shows tensile deformation dominated by the following dislocations, and shear strain appears. The deformation degree of the accumulation layer will be aggravated under continuous mining conditions. The maximum principal stress increment of the underlying bedrock is 1080.75 %, and the tensile stress is concentrated. ④ Short-wall room mining leaving section coal pillar is beneficial to reduce the deformation of accumulation layer.The research conclusions provide a reference for understanding the deformation and failure of the overlying accumulation layer on the slope disturbed by underground resource mining and seeking solutions for the protection of cultural relics in coal mining under ancient buildings.

     

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