【作者】 赵斌；

【导师】 仲志成；

【作者基本信息】 吉林大学 ， 工程硕士（专业学位）， 2017， 硕士

【摘要】 地应力是地球内部岩体属性的重要参数,是监测地震、山体滑坡以及火山活动的重要依据之一。为了实现对地下岩层空间应力大小与方向的有效监测,基于光纤光栅传感技术与平面应力状态测量原理,本文设计并研制出一种监测地下空间应力大小与方向的光纤光栅三维地应力传感器。地应力传感器采用各向异性碳纤维层积复合材料作为载体对光纤光栅进行封装,并将其做成应变传感单元;针对钻孔监测需求,三维地应力传感器整体结构采用圆柱形结构设计,九个应变传感单元组成三组应变花,每组应变花分别放置于一个圆柱形监测探头上。三个探头以一定的空间角度与机械结构组装成一体,形成了对地下空间应力大小与方向监测的光纤光栅三维地应力传感器。地应力传感器中的每个探头分别监测空间中的一个正交平面内的应力状态,将三个正交平面内的最大主应力进行力学矢量合成,最终得到空间中最大主应力的大小与方向。本文以光纤光栅传感理论与应变花测量平面应力状态原理为基础,将两种理论知识相互结合并推导出最大主应变与波长变化之间的关系,给出光纤传感技术应用于地应力测量的理论基础。对应变传感单元进行室内温度标定实验与应力加载实验,温度标定实验结果:在24.1~55℃范围内的温度系数平均值为57.3pm/℃;应力加载实验结果:在0~60Mpa量程内的应力灵敏度为58pm/MPa,应力分辨率为0.172MPa;线性拟合系数为0.99986。将三维地应力传感器埋置于水泥体中并进行应力加载实验,传感器应力加载实验结果:S1、S2探头的测量应力大小平均相对误差分别为16.31%、24.36%,方向误差的平均值分别为1.89°、2.52°;S3探头的绝对误差为0.0068MPa。实际加载应力与传感器测量的应力空间角度误差平均值为1.24°。更多还原

【Abstract】 Underground rock stress is an important parameter of rock mass properties in the earth,and it is one of the important basis for monitoring earthquake,landslide and volcanic activity.In order to realize the effective monitoring of the magnitude and direction of the spatial stress of the underground rock formation,a three-dimensional geostationary force sensor for monitoring the size and direction of underground space is designed and developed based on the principle of fiber grating sensing and plane stress state measurement.The stress sensor using an anisotropic layered composite material of carbon fiber as the carrier fiber grating package and make the strain sensing unit.According to the requirements of drilling monitoring,the whole structure of 3D inductive stress sensor adopts cylindrical structure design,and nine strain sensing units are composed of three sets of strain flowers.Each strain flowers is placed on a cylindrical monitoring probe.The three probes are assembled into a mechanical structure with a certain spatial angle and form a 3-dimensional geo-stress sensor for fiber gratings that monitor the magnitude and direction of the underground space.Each probe in the geo-stress sensor monitors the stress state in an orthogonal plane in the space,and synthesizes the maximum principal stress in the three orthogonal planes,and finally obtains the size and direction of the maximum principal stress in the space.The paper is based on the principle of fiber grating sensing and the principle of plane stress state measurement.The relationship between the maximum principal strain and the wavelength change is deduced by combining two theories,and the theoretical basis of the application of the optical fiber sensing technology to the geo-stress measurement is given.The indoor temperature calibration experiment and the stress loading experiment were carried out for the strain sensor unit,Temperature calibration test results: the average temperature coefficient in the range of 24.1 to 55°C is 57.3 pm/°C;Stress loading experiment results: The stress sensitivity in the range of 0 ~ 60 Mpa is 58 pm/MPa and the stress resolution is 0.172MPa;The linear fitting coefficient is 0.99986.The three-dimensional geo-stress sensor was embedded in the cement body and subjected to stress loading experiments.Sensor stress loading experimental results: the average relative error of the measured stress of S1 and S2 is 16.31% and 24.36%,respectively,and the average of the direction error is 1.89 °,2.52 °;the S3 probe of the absolute error of 0.0068 MPa.The mean value of the stress space angle error measured by the actual loading stress and the sensor is 1.24 °.更多还原