基于地基干涉雷达的火灾下门式钢刚架三维变形监测研究

Research on three-dimensional deformation monitoring of steel portal frames under fire based on ground-based interferometric radar

建筑火灾倒塌严重威胁人员的生命安全,地基干涉雷达可用于火灾下门式钢刚架微变形监测预警,但雷达仅能获取目标视线方向的形变,难以满足预警模型多维度数据需求,需对建筑结构目标三维变形监测进行研究。本文在论述微波信号模型的基础上,提出一种基于分布式目标成像信息的雷达等效相位中心估算方法,实现目标三维变换矩阵迭代优化,进而开展缩尺双跨门式钢刚架火灾试验,获取局部坐标系下结构目标三维变形分量,并与传统拉线式位移计监测结果进行对比。试验结果表明:多台地基干涉雷达组合监测可在真实火场下有效获取结构目标的三维变形分量,监测结果符合既有门式钢刚架结构的受火变形规律,可为火灾下建筑倒塌预警提供有效数据支持。

The collapse of building fires poses a serious threat to the safety of personnel.Research has shown that ground interference radar can be used for micro deformation monitoring and early warning of portal steel frames under fires.However,due to the fact that radar can only obtain deformation in the direction of the target line of sight,it is difficult to meet the multi-dimensional data requirements of early warning models.Therefore,it is urgent to study the three-dimensional deformation monitoring of building structural targets.On the basis of discussing the microwave signal model of the system,this article proposes a radar equivalent phase center estimation method based on distributed target imaging information,which achieves iterative optimization of the target's three-dimensional transformation matrix.Then,a scaled double span steel frame fire test is carried out to obtain the three-dimensional deformation component of the structural target under local coordinate system,and the monitoring results are compared with those of traditional wire displacement meters.The experimental results show that the combination monitoring of multiple ground-based interferometric radars can effectively obtain the three-dimensional deformation components of structural targets in real fire scenarios.The monitoring results conform to the deformation laws of existing portal steel frame structures under fire,and can provide effective data support for building collapse warning under fire.