采场覆岩变形分布式光纤监测岩体-光纤耦合性分析  

Theoretical analysis of the mechanical coupling between rock and optical fiber for distributed sensing of overlying strata deformation

作　　者：柴敬[1,2] 欧阳一博 张丁丁[1,2] 雷武林[1] CHAI Jing;OUYANG Yibo;ZHANG Dingding;LEI Wulin(College of Energy Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China;Xi'an University of Science and Technology,Ministry of Education of the Western Mining and Mine Disaster Prevention and Control of Key Laboratory,Xi'an 710054,China)

机构地区：[1]西安科技大学能源学院,陕西西安710054 [2]西安科技大学教育部西部矿井开采与灾害防治重点实验室,陕西西安710054

出　　处：《采矿与岩层控制工程学报》2020年第3期69-78,共10页Journal of Mining and Strata Control Engineering

基　　金：国家自然科学基金资助项目(51174280,51804244);陕西省教育厅科学研究计划资助项目(16JK1488)。

摘　　要：岩体与光纤之间的耦合性是决定分布式光纤感测岩体变形准确性的关键因素。通过岩层变形光纤响应特性的力学分析,结合运动学方法,提出了光纤-岩体的耦合性判据,并建立了岩层变形光纤监测模型。通过水平埋设在物理相似模型内部的传感光纤,监测不同开挖状态下关键层的结构性变形,并借助数字图像相关技术(DIC)对关键层挠度分布进行实时跟踪监测,综合分析覆岩变形特征及演化规律,并将2者监测结果进行对比分析。结果表明:当岩层变形较小时,岩体-光纤耦合性系数在0.9~1.0内,光纤应变计算的岩层挠度与DIC测量的实际岩层挠度基本一致,最大相对误差为8.9%;当岩层变形较大时,岩体-光纤耦合性系数呈断层式直线下降,直至岩层发生破断,裂缝处岩体-光纤发生脱离,光纤-岩体接触度与光纤-岩层耦合系数k值均为0;通过光纤监测数据反演,获得采动覆岩的变形范围及特征,从而反映出光纤沿线岩层移动变形的位置及程度。研究成果为分布式光纤传感技术应用于模型及现场覆岩变形监测提供了参考。The mechanical coupling between rock and fiber is the key factor to determine the accuracy of rock deformation sensing by distributed fiber.Based on the mechanical analysis of the response characteristics of fiber deformation in rock strata and the method of kinematics,the coupling criterion between fiber and rock strata is put forward,and the monitoring model of fiber deformation in rock strata is established.Through the sensor fiber embedded in the physical similarity model horizontally,the structural deformation of key layers under different excavation conditions is monitored,and the deflection distribution of key layers is tracked and monitored in real time with the help of digital image related technology.The deformation characteristics and evolution rules of overlying rocks are analyzed comprehensively,and the monitoring results of the two are compared and evaluated.The results show that when the rock deformation is relatively small,the rock-fiber coupling coefficient is within the range of 0.9~1.0,and the rock deflection calculated by fiber strain is consistent with the actual rock deflection measured by DIC,with the maximum relative error of 8.9%.When the rock deformation is large,the rock-fiber coupling coefficient drops linearly in a fault-type manner,until the rock fracture occurs and the rock-fiber is detached at the crack,and both the fiber-rock contact degree and the fiber-rock coupling coefficient k-value are 0.However,the strain curve measured by the horizontal optical fiber can be used to invert the deformation range and characteristics of mining overburden,reflecting the location and size of strata movement deformation along the fiber,as well as the size of strata affected by mining.The research results provide a solid theoretical basis for the application of distributed optical fiber sensing technology in the model and the field overburden deformation monitoring.

关 键 词：覆岩变形 分布式光纤 耦合性 模型试验 

分 类 号：TD325[矿业工程—矿井建设]