Abstract：Based on the basic theory of temperature tracer method and combined with the temperature distribution characteristic of core rock-fill dam，the gradient method and heat pulse method were compared，which can verify the disadvantage of gradient method to monitoring the concentrated leakage of core rock-fill dams. So heat pulse method based on FBG(fiber Bragg grating) sensing system was proposed for concentrated leakage monitoring in core rock-fill dam. The mathematic model of conjugated heat transfer among porous media-heat source-FBG was proposed as a theoretical basis for this method. At first，the relationship among temperature rise，seepage velocity，and heating power was obtained by numeral simulation with ADINA software. Then numerical simulation for concentrated leakage in core rock-fill dam was executed to obtain the seepage velocity distribution of every monitoring section. According to the fitting formula among temperature rise，seepage velocity，and heating power， the numerical simulation for concentrated leakage monitoring was carried out by converting the seepage velocity distribution to temperature rise distribution. The results show that the new method can be applied to exactly locating the leakage position. The smaller the distance between sensing system and downstream face of core is，the better the monitoring effect is. The higher the concentrated leakage intensity is，the more obvious the difference of temperature rise is.
