为了解决沉井施工监控中内部地形探测这一难题,在分析了探测作业环境特点基础上,提出了封闭环境下深水沉井的探测方法,利用三维多波束实时声呐系统在瓯江北口大桥成功采集到沉井内部地形数据。采用GIS技术构建了沉井内部地形三维场景数据,结合测绳探测数据和现阶段沉井取土方案,验证了探测的井底地形高程精度满足施工要求,论证了数据对井底地表形态特征的表达是可信的,表明提出的探测方法是可行的。在分析探测数据过程中发现:结合探测数据图像颜色的明暗和空间几何形态特征,能辨识出不同的取土分区和分布特征,通过GIS技术对取土分区及地形高程进行可视化分析,可以为沉井施工确定取土方式、位置和范围提供辅助数据。

To tackle the difficulty of topographic detection inside caisson during construction monitoring, we put forward a detection method for deep-water caisson in closed environment based on analyzing the operation environment. The interior topographic data of caisson was successfully captured by 3D multi-beam real time sonar system in the Oujiang Beikou Bridge. The 3D scene data of caisson’s interior topography were constructed by GIS technology. Moreover, according to rope survey data and soil excavation scheme, the accuracy of the detected topographic elevation is verified to meet the construction requirements, and the expression of surface morphology is proved credible, which indicate that the proposed method is feasible. By analyzing the detection data we found that different soil excavation zones can be identified by the brightness and shade of the detection data image with the spatial geometric morphological characteristics. Visual analysis of soil excavation zones and topographic elevation in the assistance of GIS technology will provide auxiliary data for determining the approach, position, and range of soil excavation for caisson construction.