基于智能磁性石块埋入的边坡深部变形失稳监测模型

针对边坡深部变形失稳监测存在服役环境恶劣、传感器布设困难等问题,提出基于智能磁性石块的边坡变形失稳监测方法,研制智能磁性石块及全张量磁场梯度传感器,发展基于智能磁性石块的边坡变形监测的简化磁测算法,通过智能磁性石块的位移变化反演边坡失稳过程。采用铝合金模型槽、分离式千斤顶和力传感器建立滑坡模拟系统,通过推移加载方法模拟边坡滑动。试验结果表明,当推力为2 500 N时,通过菲林软尺测得的6个特征点的水平位移与推力的曲线关系发生突变,当推力在2 500至3 100 N时,6个特征点的水平位移增加幅度迅速提高,发生失稳破坏。当推力为2 500 N时,智能磁性石块至参考点的距离、智能磁性石块的水平位移与推力的曲线关系存在拐点,此后智能磁性石块至参考点的距离、智能磁性石块的水平位移均大幅度变化。智能磁性石块至参考点的相对距离、智能磁性石块的位移等均可反映边坡变形演化并可进行失稳评价,且与菲林软尺传统的监测结果趋势基本一致。可为磁测在边坡深部变形监测的进一步研究和应用提供参考。

Monitoring model of slope internal deformation and instability based on smart magnetic rock

Abstract: There exist a number of slope deformation monitoring methods, but as for most of methods, only the surface deformation can be used to measure slope, while in the practical engineering the slope internal deformation is very important to determine the sliding surface of a slope. Although the slope internal deformation can be monitored by means of few technologies, it is very difficult to arrange and maintain these sensors. Also, the existing slope internal deformation sensors are easily influenced by extreme harsh environment, and the arrangement of equipment is not convenient for the internal deformation monitoring. In this study, slope deformation monitoring system was combined with smart magnetic rock and full tensor magnetic gradiometer. Accordingly, the simplified algorithm of magnetic survey was given for slope deformation monitoring method based on the magnetic gradient tensor and magnetic dipole, and consequently, the three dimensional positions of smart magnetic rock can be obtained in real time. Through the displacement change of smart magnetic rock in the deep internal position of slope, the sliding process and instability of slope can be evaluated. The thrust load was crucial for slope sliding when the slope sliding was the driving force type or caused by the load on the slope top. Therefore, the physical model test by driving force was used as landslide simulation system to verify the slope internal deformation monitoring system by means of smart magnetic rock and full tensor magnetic gradiometer. The landslide simulation system was established by aluminum alloy model box, separated jack and force sensor, and the sliding of slope was realized by applying driving force at the back of slope. The results showed that when the driving force was 2 500 N, there existed the turning on the curve of driving force versus critical points'' horizontal displacements measured by soft film size. When the driving force was ranged from 2 500 to 3 100 N, six critical points'' horizontal displacements increased drastically with instability failure of slope. With regard to the smart magnetic rock, there also existed the turnings on the curve of the relative distances from smart magnetic rock to reference points and smart magnetic rock''s horizontal displacements versus driving force. And then both the relative distances from smart magnetic rock to reference points and smart magnetic rock''s horizontal displacements changed sharply. It showed that the slope deformation development and slope instability evaluation can be judged by relative distances from smart magnetic rock to reference points and smart magnetic rock''s horizontal displacements, and the results were in accord with the monitoring assessment by soft film size, which can be used as reference in the further study and practical engineering monitoring. It also showed that the simplified algorithm of magnetic survey for three dimensional positions of smart magnetic rock and slope internal monitoring were effective and useful. And it was suggested that the magnetic interaction of smart magnetic rocks should be studied in order that the smart magnetic rock network can be established for slope internal deformation monitoring in the practical engineering.