时间域电磁法对墙体钢筋分辨能力研究

Resolution Study of Detecting Rebar of Reinforced Wall by Time Domain Electromagnetic Method

为有效探测钢筋混凝土中的钢筋数量、间距,提出了采用时间域电磁法进行钢筋数量、间距检测的方式.通过物理模型实验对比了同点装置、偶极装置和大定源装置3种装置的探测效果,结果表明,时间域电磁法可有效探测出保护层厚度为5 cm、直径为0.8 cm的钢筋的间距和数量,其中同点装置具有最高的分辨能力和抗干扰能力,偶极装置的探测效果次之,但对下排钢筋探测效果不明显,而大定源装置由于发射线圈较大,受周围环境的影响最大,探测效果最差.

In order to effectively detect the number and interval of concrete rebar,a Time Domain Electromagnetic Method(TDEM),which is widely used in geophysical prospecting,is proposed to detect the number and spacing of rebars.Through physical model experiment and result processing analysis,the detection effects of the same point device,dipole device and large fixed source device are compared.The results show that the time domain electromagnetic method can effectively detect the spacing and quantity of rebars with a protective layer thickness of 5 cm and a diameter of 0.8 cm,among which the same point device has the highest resolution and anti-interference ability,and the dipole device has the second detection effect,while the detection effect on the lower row of steel bars is not obvious.The large constant source device is most affected by the surrounding environment and has the worst detection effect due to its large transmitting coil.