基于近景摄影测量的高精度基坑变形监测技术研究

Research on high precision deformation monitoring technology of foundation pit based on close-range photogrammetry

目前深基坑支护变形监测工作越来越重要,传统基坑支护外观变形监测仪器主要采用水准仪、全站仪等设备,效率及自动化程度低。近景摄影测量技术具有非接触、成本低、三维立体等特点,其变形监测精度不高,从而制约了其进一步的推广和使用。文章针对近景摄影测量问题,结合基坑支护变形特点,提出基于二维图像的近景摄影基坑支护变形监测方法,从相机检校、摄影标志设计、光照条件、拍摄参数设置和数据处理系统误差分析等方面进行分析与研究。实验结果表明,在相机镜头焦距为50 mm,摄影距离为20 m的情况下,摄影监测变形误差小于0.1 mm。该研究结果为进一步推广使用近景摄影测量技术提供了借鉴与参考。

At present,the deformation monitoring of deep foundation pit support is becoming more and more important.The traditional appearance deformation monitoring instruments of foundation pit support mainly use level,total station and other equipment,with low efficiency and automation.Close-range photogrammetry technology has the characteristics of non-contact,low cost and three-dimensional property,but its deformation monitoring accuracy is not high,which restricts its further promotion and use.Aiming at the problem of close-range photogrammetry and combined with the characteristics of foundation pit support deformation,this paper puts forward a deformation monitoring method of foundation pit support based on close-range photogrammetry with two-dimensional images,and conducts analysis from the aspects of camera checking,photography logo design,lighting conditions,photographing parameters setting and error analysis of data processing system.The results indicate that,the error of deformation monitoring is less than 0.1 mm with a distance of 20 m and a focal length of 50 mm.This result can provide reference for the application of close-range photogrammetry in the foundation pit support deformation monitoring.