基于霍尔和磁阻效应的地下位移三维测量方法

发布时间：2018-07-10 17:16

本文选题：地下位移 + 三维测量　；参考：《中国计量学院》2013年硕士论文

【摘要】：摘要：滑坡灾害发生频繁、危害巨大。滑坡监测的各项内容中，地下位移的监测能直观地反映地下土体的变形情况，是滑坡监测的重点和难点。对可能发生滑坡的区域进行地下位移实时在线测量，能起到及时的预警作用。国内外对于坡体深部位移的监测，主要利用埋设在地质钻孔中的测斜仪、多点位移计和TDR同轴电缆。三种主流测量方法都不能测量出地下位移的三维变化。鉴于此，笔者提出一种基于霍尔和磁阻效应的地下位移三维测量方法。分析滑坡发生时的地质变化情况，，选取常见的旋转型滑坡、平移型滑坡和块体滑移作为测量对象。基于滑动体的局部地质构造不变性以及三维位移轮廓模型，提出测量方案：将多个圆柱形测量单元沿着共同的中轴线串接后埋入待测土体，通过测量所有相邻单元间的相对位移来实现整个地下土体位移的测量。将霍尔传感器阵列、磁钢、磁阻传感器以及屏蔽层安装在圆柱形测量单元之中，并建立三维系统坐标系。对于测量单元A中的霍尔传感器阵列与测量单元B中的磁钢，地下土体的变形会改变两者之间的相对位置。只要得到磁钢在变形前后的三维坐标，通过几何运算就能得出相对位移的大小。搭建实验平台，逐步改变霍尔传感器与磁钢间的相对位置以标定传感器。采用标定的数据，根据圆柱形磁钢的磁场分布并结合MATLAB分析得出磁感应强度（霍尔电压）等值线，进而构建等值面模型。基于等值面模型，设计采用三个呈等边三角形分布的霍尔传感器组成传感器阵列。对于空间中的一个磁钢，每一个霍尔传感器对应一个特定的霍尔电压及等值曲面。三个等值曲面相交于一点，该点的三维坐标由相应的算法得出。磁阻传感器对地磁的测量结合磁钢三维坐标的测量，可完成相邻测量单元之间相对位移的方向测量。相对位移的测量范围可由一个三维空间中的柱体表示。该柱体是三个圆柱体相交的公共部分，其大小基于霍尔传感器标定的空间范围。实验结果表明：磁钢三维坐标的测量误差保持在±5%以内，地磁测量的误差在±2%以内，相邻单元间的相对位移测量满足实际要求。
[Abstract]:Abstract: landslide disasters occur frequently and cause great harm. Among the contents of landslide monitoring, the monitoring of underground displacement can directly reflect the deformation of underground soil, which is the key and difficult point of landslide monitoring. Real-time online measurement of underground displacement in areas where landslides may occur can play a timely and early warning role. For the monitoring of deep displacement of slope body at home and abroad, the inclinometer, multipoint displacement meter and TDR coaxial cable are mainly used. None of the three main methods can measure the three-dimensional variation of underground displacement. In view of this, a 3D measurement method of underground displacement based on Hall and magnetoresistive effect is proposed. Based on the analysis of the geological changes during the occurrence of the landslide, the common rotating landslide, the translational landslide and the block slip are selected as the measuring objects. Based on the local geological structure invariance of the sliding body and the 3D displacement profile model, the measurement scheme is put forward: multiple cylindrical measuring units are connected in series along the common central axis and buried into the soil under test. The displacement of the whole underground soil is measured by measuring the relative displacement of all adjacent elements. Hall sensor array, magnetosteel, magnetoresistive sensor and shielding layer are installed in cylindrical measurement unit, and 3D coordinate system is established. For Hall sensor array in measurement unit A and magnetic steel in measurement unit B, the deformation of underground soil will change the relative position between them. As long as the three-dimensional coordinates of the magnetic steel before and after deformation are obtained, the relative displacement can be obtained by geometric calculation. The relative position between Hall sensor and magnetic steel is changed step by step to calibrate the sensor. According to the magnetic field distribution of cylindrical magnetic steel and MATLAB analysis, the magnetic induction intensity (Hall voltage) isoline is obtained by using the calibrated data, and the isosurface model is constructed. Based on the isosurface model, three Hall sensors with equilateral triangle distribution are used to form the sensor array. For a magnetic steel in space, each Hall sensor corresponds to a specific Hall voltage and equivalent surface. The three equivalent surfaces intersect at one point, and the three dimensional coordinates of this point are obtained by the corresponding algorithm. The measurement of geomagnetism by magnetoresistive sensor combined with the measurement of 3D coordinate of magnetic steel can accomplish the direction measurement of relative displacement between adjacent measuring units. The measurement range of relative displacement can be expressed by a cylinder in a three-dimensional space. The cylinder is a common part of the intersection of three cylinders, and its size is based on the spatial range calibrated by Hall sensors. The experimental results show that the measurement error of 3D coordinate of magnetic steel is kept within 卤5%, and the error of geomagnetic measurement is less than 卤2%. The relative displacement measurement between adjacent elements meets the practical requirements.
【学位授予单位】：中国计量学院
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P642.22;P227

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