三维物理模型模拟深部巨厚砾岩下综放开采地表移动

Simulate of the surface movement of fully-mechanized caving mining under the deep thick conglomerate using 3D physical model

为了研究深部开采巨厚砾岩关键层对矿山地表移动变形的影响机理。以千秋煤矿为背景,采用三维物理模型试验,利用压力传感器、多点位移计、分布式光纤传感等多种手段监测了覆岩及地表移动变形动态演化过程,对采动巨厚砾岩与矿山地表移动变形的内在联系机理进行了研究。结果表明,分布式光纤可准确监测到关键层和地表的移动变形量,巨厚砾岩作为主关键层,控制着地表移动变形,并有效减缓了覆岩变形由下向上传递给地表,且由于煤层埋藏深度大,主关键层未破断,地表下沉量和变形值都较小;预测随着工作面继续推进,巨厚砾岩主关键层将会达到极限跨距而破断失稳,采场将发生强矿压动力显现现象,地表出现台阶性下沉,甚至会产生地表裂缝。

In order to study the influence mechanism of the key stratum of huge-thick conglomerate deep mining on ground surface movement and deformation,the Qianqiu Coal Mine was taken an example in this paper.The three-dimensional physical model test was used to monitor the dynamic process of mining overburden and ground surface movement by means of pressure sensor,multi-point displacement meter and distributed optical fiber sensor,thus exploring the intrinsic relationship between deformation of huge-thick conglomerate and surface movement.The results show that the distributed optical fiber sensing technology is suitable for the ground surface movement and deformation monitoring in physical model test.As the main key stratum,the huge-thick conglomerate controls the ground surface movement and effectively slows down the deformation of the overburden from the bottom to the surface.And the depth of the coal seam is large,the huge-thick conglomerate is not broken and unstable,the maximum subsidence and deformation value of the surface are comparatively smaller due to its protection.It is predicted that as the working face continues to advance,the huge-thick conglomerate would break and lose stability when it reaches the ultimate span,the dynamic phenomena of strong rock pressure occur in the stope,and the surface subsides would appear stepped subsidence and even ground fissures.