摘要
通过对铁路隧道整体式衬砌试件进行地质雷达非接触式检测模拟试验,研究不同检测距离(地质雷达天线底面距衬砌试件表面的距离)对地质雷达扫描图图像质量及检测精度的影响。试验结果表明:(1)在检测距离为10,20 cm的条件下,采用400 MHz地耦屏蔽天线能够对隧道整体式衬砌进行地质雷达非接触式检测。(2)随着检测距离增大,所获得的地质雷达扫描图图像质量降低,需对地质雷达反射波采取数字滤波、调整增益系数等处理措施才能够达到满意的效果;地质雷达图像质量与仪器设备有一定关系,在实际工程中,检测前应先通过试验验证合理的检测距离。(3)在地质雷达扫描图中,可识别试验设计方案中预设的各种工况类型,而且衬砌背后回填不密实、空洞等的位置和范围都与天线密贴衬砌情况基本一致,满足地质雷达扫描图定性解释的要求。(4)衬砌厚度检测结果的误差随检测距离的加大而增大,但是除极少数测点误差较大外,其他测点的误差范围是接近天线密贴衬砌情况的,能够保证衬砌厚度检测值的准确性;通过对非接触式检测结果进行修正,可使其达到接触式检测的效果;衬砌背后回填不密实层和空洞厚度检测值的误差范围与天线密贴衬砌的情况一致。本文研究成果将对开发车载地质雷达检测系统,以及实际工程中地质雷达非接触式检测技术的应用具有一定的实用价值。
The simulation test for the integral lining specimens of railway tunnel by means of non-contact ground penetrating radar（GPR） detection is performed.The influences of different detection distances（the distance from the bottom of GPR antenna to the lining specimen surface） on the image quality and detection accuracy of GPR scans are studied.The test results show that：（1） The non-contact GPR detection on the integral lining can be performed by means of 400 MHz ground-coupled antenna with 10 or 20 cm detection distance.（2） With the increasing detection distance,the image quality of GPR scans decreases,and satisfactory images can be obtained if some measures such as using digital filtering and adjusting gain coefficient on GPR back wave are adopted.GPR image quality and equipment have particular concern,so the appropriate detection distance should be chosen through experiments before detecting in actual projects.（3） In the GPR scans,a variety of preset work conditions can be identified in the experimental design.The location and range of uncompacted backfill,cavity behind the lining,etc.are similar to those obtained when the antenna closes up to the lining specimen surface;and GPR scans can be interpreted qualitatively.（4） The deviation of test results of lining thickness increases with the increasing detection distance.However,apart from a few measuring points having larger deviation,the deviation range of other measuring points is similar to that obtained when the antenna closes up to the lining specimen surface,which can ensure the accuracy of lining thickness.The non-contact detection values after amendment can be consistent with the contact detection values.The deviation ranges of uncompacted backfill and cavity thicknesses behind the lining agree with those when the antenna closes up to the lining specimen surface.The study will be practical value for the development of the vehicle-system GPR detection and the application of non-contact GPR detection technology in actual project.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2011年第9期1761-1771,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
铁道部科技研究开发计划项目(2008G017-A)
关键词
隧道工程
地质雷达
衬砌
非接触式检测
模拟试验
tunnelling engineering
ground penetrating radar（GPR）
lining
non-contact detection
simulation test
