【作者】 王静；

【导师】 隋青美；

【作者基本信息】 山东大学 ， 检测技术与自动化装置， 2011， 博士

【摘要】 随着我国现代化建设和可持续发展战略的实施,在交通、水利水电与矿山等领域正在或即将修建大量的隧道(洞)等地下工程,随着重大交通与水电工程向西部山区转移以及矿山采掘深度的增加,地下工程施工中所遭遇的水文地质条件日益复杂,突涌水、塌方等高风险地质灾害呈现上升趋势,造成了严重的人员伤亡与经济损失。在目前地下工程地质灾害监测技术相对落后的情况下,地质灾害的实时监测与预测已经成为亟待解决和突破的关键科技难题。光纤光栅传感技术的不断发展为解决该难题提供了可行的途径,但目前光纤光栅传感器种类少,传感系统功能简单、测量参数单一,且传感器信号提取及分析技术落后,不能有效剔除啁啾效应的影响,尚不能满足地下工程地质灾害实时监测与预测的需要。针对上述问题,本文以光纤Bragg光栅(fiber Bragg grating,简称FBG)传感理论与技术研究为突破口,以重大地下工程地质灾害模型试验为依托,在深入分析光纤光栅本征参数与应变分布对反射光谱特性影响的基础上,提出了基于光谱中心波长位置约束的光栅光谱重构理论及其改进遗传算法优化方法,实现了光纤光栅啁啾效应的快速准确识别与剔除,提出了传感器数值仿真优化设计方法,研制了高灵敏度渗压传感器、新型应变传感器、靶式流速传感器、微型位移传感器与多点位移传感器；构建了大容量、多参数光纤光栅实时监测网络,相关研究成果已在不同地下工程地质灾害模型试验中得到成功应用。本文的主要研究工作如下：(1)针对光纤光栅光谱特性同时受多个参数影响这一基础问题,基于光纤光栅传输矩阵理论及应变传感模型,开发了光纤光栅光谱仿真程序,揭示了光纤光栅本征参数及应变分布对反射光谱特性的影响规律,尤其是沿光栅的应变分布对光栅反射谱中心波长、反射率及带宽等因素的影响,通过两端固定压杆调谐光纤光栅试验,获得了光纤光栅在非均匀应变条件下的光栅反射谱,验证了光纤光栅数值分析的有效性,为光纤光栅参数重构与传感器研究奠定了理论基础。(2)针对以往光纤光栅参数重构尤其是应变分布重构效果差且收敛速度慢的难题,提出了基于中心波长位置约束的光纤光栅参数重构理论及其改进的遗传算法优化方法,解决了以往光纤光栅参数重构中未考虑中心波长相对位置而导致重构效果差的难题,显著改善了重构的非唯一性和置信度,开发了光栅本征参数与应变重构程序,系统的开展了光纤光栅参数重构数值试验,结合两端固定压杆调谐光纤光栅试验,验证了该重构方法的有效性、适用性和可操作性,形成了种光纤光栅参数精确重构方法。(3)针对光纤光栅传感器设计方法落后的现状,基于有限元数值分析方法,提出了光纤光栅传感器优化设计方法,构建了光纤光栅重构理论与标定试验相结合的光纤传感器优化设计平台。针对目前光纤传感器种类少、与周围介质匹配性差的难题,突破了光纤光栅传感技术用于渗压、流速等传感测量的技术瓶颈,采用基于有限元理论的光纤光栅传感器优化设计方法,研制了高灵敏度光纤光栅渗压传感器与靶式光纤光栅流速传感器,同时基于被测物体基体材料研制了与周围介质匹配性能好的光纤光栅应变传感器,开发了微型光纤光栅位移传感器与多点位移传感器,构建了适用于地下工程地质灾害实时监测与信息识别的新型传感器体系。(4)针对目前光纤传感系统简单、测量参数单一的难题,基于波分复用与空分复用理论,构建了多参数、大容量光纤光栅传感系统,并采用Labview与C++Builder开发了地下工程灾害实时监视与在线分析软件,实现了多元数据的同步采集与实时显示。(5)针对地下工程灾害监测中传感器灵敏度低、防水性能差的缺陷,将光纤光栅传感系统用于工程灾害关键物理参数的实时监测中。针对典型的地质灾害,开展了煤矿突涌水模型试验、隧道围岩稳定性模型试验与分区破裂模型试验等大型模型试验,揭示了温度、应变、位移、渗压、流速等参数对岩体的破坏过程尤其是灾害发生前兆信息的响应特征,建立了地下工程地质灾害前兆判别标准,形成了基于光纤传感技术的地下工程灾害实时监测与预测系统,对解决地下工程地质灾害的实时监测与预测难题具有重要的理论意义和工程价值。更多还原

【Abstract】 As modernization construction and sustainable development strategy are carried out in China, a large number of tunnels (holes)and other underground engineering are being or are about to be constructed in the transportation, water conservancy and hydropower, mining and other areas. Since the major transportation and hydropower engineering turn to the western mountains and the depth of mining increases, the hydrogeological condition suffered by the underground engineering construction are increasingly complicated. As a result, more and more geological disasters such as sudden water inrush and collapse with high risk occur, which induce to serious casualties and economic losses. However, the technology of monitoring underground engineering geological hazards is relatively backward at present. It has become a key scientific problem to be solved that monitoring and forecasting the geological hazards real-timely. Fiber grating sensing technology provide a feasible approach to solve this problem. Unfortunately, since there are a few kinds of FBG sensors, and the system with simple function can monitor single parameter, in which signals extraction and analysis technology is poor and chirp effects could not be effectively removed, FBG sensing technology can not well satisfied with the needs of real-time monitoring and forecasting underground geological disasters currently.In response to above problems, regarding fiber Bragg grating sensing theory and technology as breakthrough in this dissertation, based on the significant underground engineering geological hazards model test, the influence of FBG intrinsic parameters and strain distribution on the reflective spectral characteristics is analyzed, and FBG parameters reconstruction theory based on central wavelength constraint and optimization method on the basis of improved genetic algorithm are both proposed. Therefore, fast recognition and elimination of FBG chirp effects is realized. The dissertation presents numerical simulation optimization design method of FBG sensors. Consequently, FBG seepage pressure sensors with high sensitivity, new FBG strain sensors, target-type FBG flow velocity sensors, micro FBG displacement sensor and multipoint FBG displacement sensors have been developed. FBG multi-parameter sensing system is also established and the system has been successfully used in the different underground engineering geological hazards model tests. The major research is expressed as followings:(1) According to the basic problem that FBG spectral characteristics is conditioned by multiple parameters, FBG spectral simulation program based on FBG transfer matrix theory and fiber grating strain sensing model has been developed. The influences of FBG intrinsic parameters and strain distribution on the spectral characteristics are disclosed. Especially, the influences of strain distribution on central wavelength, reflectivity, and bandwidth have been revealed. In tuning FBG by two ends fixed compression bar experiment, the reflection spectrums of FBG which is tuned by uneven strain is obtained, and the validity of FBG numerical analysis work is verified. As a result, the research lays a theory foundation for reconstruction of FBG parameters and study on FBG sensors.(2) In response to that traditional FBG parameters reconstruction theory and especial strain distribution reconstruction theory both have poor effect and slow convergence speed, FBG parameters reconstruction theory based on central wavelength constraint and optimization method on the basis of improved genetic algorithm is presented, which solves the difficult problem that the reconstruction theory has poor effect because of neglecting central wavelength and which significantly improves the non uniqueness and the confidence of reconstruction. FBG intrinsic parameters and strain reconstruction program has been developed, and parameters reconstruction numerical simulation experiments are comprehensively carried out. Through tuning FBG by two ends fixed compression bar experiment, the validity, applicability and practicability of the novel reconstructing method have been verified. Consequently, a novel method of accurately reconstructing FBG intrinsic parameters and strain distribution is generated.(3) In the current situation that the design technology of FBG sensor is backward, numerical simulation optimization design technology of FBG sensors based on finite element numerical analysis theory is presented. Optimization design platform for FBG sensors is established based on reconstruction theory and calibration experiments. For there are only a few kinds of FBG sensors which have poor matching ability with ambient medium, technological bottlenecks of measuring seepage pressure and flow velocity using FBG sensing technology are resolved. Based on the optimization design technology of FBG sensors adopting finite element theory, the FBG seepage pressure sensor with high sensitivity and target-type FBG flow velocity sensor are exploited. At the same time, FBG strain sensor based on matrix material of measured object is developed, which has good matching ability with ambient medium. The micro FBG displacement sensors and multipoint FBG displacement sensors are also designed. Ultimately, novel FBG sensor system suitable for monitoring underground engineering geological hazards and identifying information real-timely is constructed.(4) For the problem that FBG sensing system is simple and it can not monitor various parameters, FBG multi-parameter sensing system adopting wavelength division multiplexing and space division multiplexing technology is constructed. The software which can monitor underground engineering disasters real-timely and analysis information on-line is also developed based on Labview and C++Builder. As a result, it realizes synchronous acquisition and real-timely display of multivariate data.(5)According to the defects that the traditional FBG sensors used in underground engineering have low sensitivity and poor waterproof property, the FBG sensing system has been used to real-timely monitor key physical parameters of engineering disasters. Regarding to the typical geological disasters, coal mining water inrush model test, stability of tunnel surrounding rock model test, zonal disintegration model test and other full-scale model test are carried out. It reveals the influence of the parameters such as temperature, strain, displacement and seepage pressure on the damage process of the rock, and the especial response characteristics on the precursory information of hazard. Consequently, judging standard of underground engineering geological disasters precursor information has established, and underground engineering disasters real-timely monitoring and forecasting system based on the fiber grating sensing technology has formed. It has significant theory significance and engineering value to realize real-timely monitoring and forecasting underground engineering disasters.更多还原