糯扎渡水电站大坝渗漏的稳态检测研究

Static Detection on Seepage of Nuozhadu Dam

土石体具有较低的热传导特性,温度场分布较均匀。当存在微量渗流且渗流水温与土温不同时,因渗流流动速度缓慢、稳定,土水间有充足的时间和充分的接触空间改变温度场。为监测糯扎渡堆石土坝反滤料区中的渗流情况,利用光纤Bragg光栅传感器在温度变化时波长会发生移位的特性,对不同渗流条件下土石体中正温度系数(PTC)热敏电阻稳定温度场分布进行了试验研究。结果表明,渗流流速与稳定温度的升降有一定的对应规律,可根据温度场信息,建立判识渗流状态的科学依据。

As the low thermal conductivity of earth-rock material, the temperature distribution in earth-rock aggregate is more uniform. When there is micro seepage in earth-rock aggregate and temperature difference between water and earth-rock, the temperature distribution in earth-rock aggregate will change because the slower flow will provide enough contact time and space. For monitoring the seepage in filter material zone of Nuozhadu Core Rockfill Dam, the stable temperature fields of positive temperature coefficient （PTC） thermal resistor in earth-rock under different flow conditions are experimentally studied by using fiber Bragg grating sensors as its wavelength can shift with temperature change. The experiments indicate that the variation of seepage flow velocity is related to the change of stable temperature. Consequently, the seepage state ean be estimated by the information of temperature field.