为了深入探究采场上覆巨厚复合关键层的移动变形规律，以义马矿区的地质条件为背景，利用计算机软件(KSPB)判别覆岩关键层位置;根据高位关键层与工作面推进长度的空间位置关系，结合符拉索夫厚板理论对其进行力学分析与计算;搭建三维立体模型(3.6 m×2.0 m×2.0 m)进行物理模拟试验，采用压力传感器测试采场支承压力，分布式光纤传感技术(BOTDA)监测覆岩动态变形过程，多点位移计测试岩层内部位移，并将3种测试结果进行综合对比分析。结果表明:复合关键层破断距理论计算值与物理模型试验测量值基本一致，传感光纤频移峰值在数值、位置、形状上的变化可反映覆岩关键层弯曲变形、破断、回转的动态演化过程;当工作面1推进至960 m时，40 m厚亚关键层一细砂岩(煤层上方112 m位置)中的传感光纤V11出现了4次频移峰值，分别为438.98,313.85,304.27和288.97 MHz，发生了4次破断，初次破断距为368 m，周期破断距为186 m，处于垮落带;160 m厚亚关键层二下组巨厚砾岩(煤层上方225 m位置)中的传感光纤V₁₂出现了1次频移峰值，为165.94 MHz，仅发生1次破断，初次破断距为736 m，但结构未失稳，处于裂隙带;250 m厚主关键层上组巨厚砾岩(煤层上方386 m位置)中的传感光纤V₁₃最大频移峰值为38.61 MHz，远远小于光纤V₁₁和V₁₂的频移峰值，仅发生微小弯曲变形，处于弯曲下沉带。工作面2覆岩变形规律与工作面1趋势基本一致，但关键层在工作面1的破断距离比工作面2大。随开采范围增大，巨厚复合关键层自下而上逐步发生破断，会出现同步和非同步破断现象，增大了采场围岩失稳的不确定及控制难度，易诱发矿井动力灾害。

In order to study the migration and deformation law of overlying composite key stratum in stope,based on the geological condition of Yima mining area,the position of overlying key stratum is determined by computer software (KSPB). Combined with Власов thick plate theory,the mechanics analysis and calculation are carried out according to the spatial relationship between the high position key stratum and the advancing length of the working face. A three- dimensional model (geometry size:3. 6 m×2. 0 m×2. 0 m) is constructed to carry out physical simulation test. In the simulation,the pressure sensors are used to test the abutment pressure in stope,the distributed optical fiber sensing technology (BOTDA) is used to monitor the dynamic deformation process of overlying stratum,and the multi-point dis- placement meter is used to test the internal displacement of strata. Thus,a comprehensive comparison analysis of the three measurement results is carried out. The results show that the theoretical values of the breaking interval of the composite key stratum are basically consistent with the measured values of the physical model test. The variation in value,position and shape of the frequency shift peak of the sensing optical fibers can reflect the dynamic evolution process of bending deformation,breaking and rotation of the overlying key stratum. When working face 1 is advanced to 960 m,the sensing fiber V11 ( located in the 40 m thickness fine sandstone sub-key stratum 112 m above the coal seam) occurs four frequency shift peaks,438. 98,313. 85,304. 27 and 288. 97 MHz respectively. The key stratum is fractured for 4 times,the initial breaking interval is 368 m,and the periodic breaking interval is 186 m,the key stratum is in caved zone. Sensing optical fiber V12 in the second group of the 160 m thickness conglomerate sub-key stratum (225 m above the coal seam) has a peak frequency shift of 165. 94 MHz,and the key stratum is fractured for only once. The initial breaking interval is 736 m,but the structure is not unstable and it is in the fractured zone. The maxi- mum frequency shift peak value of the sensing fiber V13(located in the 250 m thickness conglomerate key stratum 386 m above the coal seam) is 38. 61 MHz,which is much smaller than that of V11 and V12 . It occurs only minor bending deformation and is in the bending subsidence zone. The deformation law of overlying strata in working face 2 is basical- ly the same as that in working face 1,but the breaking interval of key strata in working face 1 is larger than that in working face 2. With the increase of mining scope,the super-thick composite key strata has fractured gradually from bottom to top,and synchronous and asynchronous fracture phenomena would occur,which increases the uncertainty and control difficulty of surrounding rock instability in stope and easily induces mine dynamic disaster.

1 巨厚复合岩层破断距的理论计算

   1.1 力学模型的建立

   1.2 计算条件及结果

2 物理相似模拟试验

   2.1 工程地质概况

   2.2 相似常数

   2.3 模型铺装

   2.4 试验测试系统

3 岩层变形的光纤响应特性

4 实验结果及分析

   4.1 光纤监测复合关键层变形

   4.2 工作面支承压力分布

   4.3 工作面1,2关键层移动变形对比

5 结论