基于电阻率的混凝土裂缝测量方法

基于四探针电阻率测量技术,依据试验测得的混凝土表观电阻率变化确定裂缝位置.在考虑到干燥环境、潮湿环境和输入电流方向对裂缝导电能力影响的前提下,采用数值模拟技术探讨了表观电阻率随裂缝深度的变化规律,并将实际裂缝简化为等效裂缝,进而提出裂缝等效电路和等效电阻的方法,研究了表观电阻率与裂缝密实度的关系.结果表明,依据电阻率测量方法可以准确地找出裂缝位置,裂缝深度和密实度与表观电阻率变化有较好的相关性;在干燥环境下,输入电流方向垂直于裂缝时表观电阻率随着裂缝深度或裂缝等效电阻率的增加而增大,输入电流方向平行于裂缝时表观电阻率随裂缝深度或裂缝等效电阻率的增加而减小;在潮湿环境下,输入电流方向垂直于裂缝时表观电阻率不随裂缝深度或裂缝等效电阻率的变化而改变,输入电流方向平行于裂缝时表观电阻率随裂缝深度或裂缝等效电阻率的增加而减小.

Concrete crack measurement by electrical resistivity

The location of the crack can be found by the change of the apparent resistivity,based on four-probe electrical resistivity measuring technique.Considering the influence of the environment and the direction of electrical current on the conductive capacity of crack,the change of apparent resistivity with crack depth was obtained by numerical simulation method.Crack equivalent circuit and resistance method is proposed to study the relationship between the apparent resistivity and the crack bridge density, by simplifying the actual crack into equivalent one.The results indicate that the location of the crack can be precisely found by electrical resistivity measuring technique,and there is a preferable correlation between the change of the apparent resistivity and the crack's depth and bridge density.In dry environment,when the direction of electrical current is perpendicular to the crack,the apparent resistivity value increases with the increase of crack depth or crack equivalent resistivity,when the direction of electrical current is parallel to the crack,the apparent resistivity value decreases with the increase of crack depth or crack equivalent resistivity.In moist environment,when the direction of electrical current is perpendicular to the crack,the apparent resistivity value doesn't change with crack depth or crack equivalent resistivity,when the direction of electrical current is parallel to the crack,the apparent resistivity value decreases with the increase of crack depth or crack equivalent resistivity.