采场上覆关键层运移的模拟实验检测

在传统矿山压力理论的基础上，用光纤Bragg光栅传感器研究采场上覆关键层运移过程中的内部应变。以某煤矿30101综采工作面为对象，实验室模拟工作面上覆岩层变形的过程，在3 m平面模型上使用4个光纤Bragg光栅传感器，制作了3 000 mm×1 340 mm×200 mm的相似材料模型，几何相似比1∶100，同时在关键层的位置布置2条全站仪测线。实验表明，光纤光栅传感器监测出了关键层的初次垮落、周期性垮落过程，关键层初次破断时光纤光栅传感器波长漂移量曲线呈尖峰状，周期性破断时光纤光栅传感器波长漂移量曲线呈高原状，有一个持续的时间。30101工作面顶板初次垮落及周期来压步距分别在48.5~51.7 m与10.4~20.8 m，实验与现场矿压观测结果基本一致。实验实现了上覆关键层所受载荷的实时监测，载荷变化符合指数余弦函数规律。

Monitoring movement laws of overlying key strata for coal mining in similar model

Based on the traditional rock pressure theory，the fiber Bragg grating sensors were used to study the internal strain caused by the overburden key strata movement.This study was conducted for the fully mechanized working face 30101 of a coal mine in China.The deformation of the overburden key strata during mining was simulated in the laboratory with 3 m plane stress physical model.The model size was 3 000 mm×1 340 mm×200 mm with a geometric similarity ratio of 1∶100.Four fiber Bragg grating sensors and two total station survey lines were installed in the model for the overburden strata movement monitoring.The results of the study show that the fiber Bragg grating sensors successfully detect the initial weighting and the periodic weighting of the key strata.A sharp peaked wavelength shift curve of fiber Bragg grating sensor indicates the initial weighting of the key strata，and the wavelength shift curve with a peak that is maintained for a short time indicated the periodic weightings.The initial weighting and the periodic weighting distance of the roof strata of the fully mechanized working face 30101 are 48.5-51.7 m and 10.4-20.7 m，respectively.The experimental results agreed well with the in-situ measurements.This study，successfully monitored the load on the overburden key strata in real time，which are proved to be in accord with exponential cosine function.