采场覆岩离层的分布式光纤检测实验研究

发布时间：2018-02-07 16:24

本文关键词： 离层相似材料模拟实验分布式光纤变形检测 BOTDA 光纤光栅传感　出处：《西安科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：煤层开挖之后将会造成上覆岩层的运动甚至破断,并在上覆岩层中可能形成采动离层,离层是覆岩运动的一种存在形式。采场覆岩运移过程中的离层产生和发育规律的研究和注浆充填减沉、离层水害防治以及矿井瓦斯类灾害防治等现场问题直接相关,所以对采空区上方地层中离层的产生条件、扩展规律以及在上覆岩层中的分布情况进行研究就十分必要。传统的离层检测方式一般为地质雷达探测、钻孔窥视探测和地震技术探测等方式。针对光纤传感装置能够通过埋入被测对象从而可以对被测结构的内部变形状态以及受力状态进行监测的优势,提出将分布式光纤变形检测这一全新的测试方法用于采动覆岩离层发育规律的研究中。本文对覆岩离层产生的机理、覆岩离层形成的力学结构、光纤光栅传感检测机理和分布式光纤变形检测机理做了介绍。设计了尺寸为长2000mm、宽200mm、高1150mm的相似材料物理模型,并在其中分别布置了百分表位移计、光纤光栅传感器和φ0.9mm紧套单模光纤,用来检测模型中的覆岩离层发育,并通过定位实验确定了分布式光纤和模型的对应位置关系。对覆岩运动破断规律、岩层下沉量和分布式光纤检测结果进行了总结分析,并将分布式光纤检测结果分别与光纤光栅测试结果、岩层下沉量百分表测试结果进行了对比分析。研究表明,BOTDA分布式光纤变形检测技术能够很好的对模型中的覆岩离层进行检测,较好的体现出了离层的产生位置和发育规律。不同推进距离下中心频移的分布曲线中出现频移阶跃的光纤节点是产生覆岩离层的可疑位置。在工作面推进过程中,在传感光纤沿线上某点所受到的拉力处于逐渐增大的阶段,此点位下方岩层可能产生离层。
[Abstract]:After the coal seam is excavated, it will cause the movement or even break of the overlying strata, and may form the mining separation layer in the overlying strata. Separation layer is an existing form of overlying rock movement. The formation and development of separation layer in the process of overburden movement in stope is directly related to the field problems, such as grouting filling and reducing subsidence, prevention and control of water hazard and prevention of mine gas disaster, etc. Therefore, it is necessary to study the formation conditions, the spreading rules and the distribution in the overlying strata of the strata above the goaf. In view of the advantages of optical fiber sensing device which can be used to monitor the internal deformation state and the stress state of the tested structure by embedding the object under test. In this paper, a new method of distributed optical fiber deformation detection is proposed for the study of the development law of overlying strata. In this paper, the mechanism of the formation of overlying strata and the mechanical structure of the strata are discussed. The detection mechanism of fiber grating sensor and the principle of distributed fiber deformation detection are introduced. A physical model of similar material is designed, which is 2000mm in length, 200mm in width and 1150mm in height, in which the displacement meter of percentile is arranged separately. The fiber Bragg grating sensor and 蠁 0.9mm compact single-mode fiber are used to detect the development of the overburden layer in the model, and the corresponding position relationship between the distributed fiber and the model is determined by the localization experiment. The breaking rule of the overburden motion is obtained. The results of rock subsidence and distributed fiber detection are summarized and analyzed, and the results of distributed fiber detection are compared with those of fiber Bragg grating (FBG). The results of the rock subsidence percent meter are compared and analyzed. The results show that BOTDA distributed optical fiber deformation detection technology can detect the overburden layer in the model well. The location and development law of the separation layer are well reflected. The fiber node with frequency shift step in the distribution curve of center frequency shift under different propulsion distance is the suspicious position to produce the overburden rock separation layer, and in the process of working face advance, there is no doubt that the fiber node with frequency shift step in the distribution curve of center frequency shift under different propulsion distance is the suspicious position. The tensile force at a certain point along the sensing fiber is gradually increasing, and the rock layer below this point may be separated.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD326

【相似文献】