【作者】 陈池；

【导师】 周宜红；

【作者基本信息】 武汉大学 ， 水工结构工程， 2013， 博士

【摘要】 面板堆石坝的面板表面变形和滑坡体地下深部变形位移监测是其稳定性评价的重要手段,已经在大坝、岩体稳定性预测预报中得到大量应用。但是精度高、稳定性好的形监测技术远远跟不上国家经济建设发展,尤其是随着我国近些年来对水利工程投资的大幅度上升,实时、准确地监测坝体、边坡变形等稳定问题显得十分重要。为适应大坝工程监测的需求,选择近年来发展起来的光纤传感监测技术,结合面板堆石坝和边坡监测工程实践,针对目前监测技术的不足,开展基于缠绕的分布式光纤传感技术研究。首先分析了分布式光纤传感变形监测方法的特点,其次建立了缠绕式光纤应变传感器的物理模型,基于光纤传感器监测机理,分析该分布式光纤位移—光损关系,再次提出了一种基于缠绕的分布式光纤应变传感测量装置,开展了该分布式光纤传感器性能试验研究,最后将分布式光纤传感器监测系统应用于工程实际。通过对以上内容的研究,主要取得了以下的成果：1)建立了缠绕式光纤应变传感器的物理模型,研究了基于螺旋的分布式光纤传感器监测机理,探索了岩层间距变化、不同岩层倾角对位移—光损耗的关系的影响规律。结果表明：宜采用波长1550nm和1310nm的组合光源监测系统,既能使系统有较小的初始感知位移,又能使系统有较大的测量范围；分布式光纤光损耗的主要影响因素除滑动位移量外,还与岩层间距(夹层厚度)、岩层滑移角度、入射光波长以及光纤类型有关。采用空心橡胶棒,可增长测试路径,扩大位移量程,进一步提高事件点的定位精度。2)提出了一种基于缠绕的分布式光纤应变传感测量装置,分析了橡胶管直径、螺旋间距对传感器灵敏度的影响规律。结果表明：在光纤光损耗和变形位移曲线的有效区域内,光纤的变形位移与光损耗基本呈线性关系,在变形位移一定的条件下,直径越大的橡胶管,光纤感知位移变化的灵敏度就越低；螺旋间距越大的光纤,感知位移变化的灵敏度也越低,采用直径为40mmm、螺旋间距为15mm的橡胶管的光纤传感器既能保证有较高灵敏度又能保证有较大的动态测量范围。3)将分布式光纤埋设在堆石坝面板,监测其变形,给出了相应监测方法,即首先通过混凝土面板堆石坝有限元分析计算,分析出堆石坝面板位移变形最大区域,最后确定光纤传感器的埋设位置和优化光纤布控方式,可大量节省光纤埋设数量,降低成本。4)将基于缠绕的分布式光纤传感器植入黄草坪深部岩体内,与侧斜监测结果对比,结果表明,基于缠绕的分布式光纤传感器与传统测斜仪所反应的位移变形实测数据一致性良好,所研制的传感器性能优越、灵敏度高,稳定可靠。更多还原

【Abstract】 It is an important means to evaluate the stability of the panel surface of concrete face rock fill dam through monitoring Deformation and landslide deep body underground displacement, which has been widely used in stability prediction of the dam and the rock mass. But the shape measurement technology for high accuracy, good stability is far behind the development of national economy, especially in the part of the water conservancy project investment increased significantly in recent years, so real-time, accurate monitoring of dam, slope deformation stability problem is very importantIn order to meet the demand of dam monitoring, fiber optic sensing technology has been developed in recent years, combined with the concrete face rockfill dam and slope monitoring engineering practice, in view of the current shortage of monitoring techniques, to carry out research on distributed optical fiber sensing technology based on winding. Firstly, the characteristic of deformation monitoring method of distributed optical fiber sensor was analyzed, then a physical model of winding fiber optic strain sensor was established. Based on fiber optic sensor monitoring mechanism, the relation of distributed optical fiber displacement and optical loss was analyzed. again a kind of distributed optical fiber strain sensor is put forward. An experimental study was conducted on the performance of optical fiber sensors distributed. finally the monitoring system of distributed optical fiber sensor was applied to practical engineering. Based on the above studies, the following main results are made:(1) A physical model of winding fiber optic strain sensor was established. the monitoring mechanism was studied for the spiral optical fiber sensor. the effect of different strata and strata dip angle on displacement optical loss were explored. The results show that:the combined light source monitoring system at1550nm and1310nm, can make the system initial sensing displacement smaller, also can make the system wide measurement range; the main factors affecting the distributed fiber optical loss in addition to sliding displacement, and spacing (rock interlayer thickness), rock slip angle the wavelength of the incident light, and fiber type. The use of hollow rubber rod, can increase the test path, enlarge the displacement range, and further improve the positioning accuracy of event points. (2) a kind of distributed optical fiber strain sensing measurement device were put forward. the effect of rubber tube diameter, coil pitch on the sensitivity of the sensor were researched. The results show that:in the optical fiber loss and effective regional deformation displacement curve, displacement and the optical loss of linear relationship between deformation and displacement, in certain conditions, the greater the diameter of the rubber tube, the lower is the optical fiber sensing displacement sensitivity; the more fiber coil pitch more, the lower is the perceived displacement sensitivity, the diameter of40mm, spiral spacing for rubber tube optical fiber sensor15mm can guarantee the high sensitivity and can guarantee the dynamic range is larger.(3) The distributed optical fiber were embedded in the concrete face rock fill dam to monitor the deformation. Firstly, through the finite element analysis and calculation of concrete face rock fill dam, the maximum area of the rock fill dam displacement were analyzed. Finally the position of the embedded optical fiber sensors and fiber arrangement optimization method were determined, which can save a large number of embedded optical fiber, reduce costs.(4) The distributed optical fiber sensor based winding were implanted in deep rock mass of yellow lawn, and compared with the oblique monitoring results. The results show that:the displacement reaction of distributed optical fiber sensor and the traditional inclinometer deformation data consistency was good at sensor performance. The distributed optical fiber sensor based winding is high sensitivity, stable and reliable.更多还原