摘要
本文在回顾了我国土坝渗流观测用测压管的基本情况后,计算了测压管的水位滞后时间。发现,通常采用的井式粗管的水位滞后时间并不比点式细管的长,且在多数情况下都是容许忽略不计的。可见,在库水位和管水位过程线上的峰谷不对应主要是由于所测渗流尚未稳定的缘故。对于不稳定渗流浸润线的位置,宜通过试绘瞬态稳定流网图,将图中的位置同由测压管水位(经滞后时间改正)线换算的位置比较吻合时方可获得,文中还举例对瞬态流网图的特性,以及今后如何更好地开展渗水压力观测等问题提出了看法或建议。
A fter a review of the basic situation of earth dam seepage observation in China, it has been found that the time lag of open standpipe piezometeric level of the well-type large-diameter tube usually is not longer than that of the point-type small-diameter tube, and it can be neglected in most cases. Thus, it can be concluded that the inconsistency of peak- valley on water-level duration curves of the reservoir and piezometers results from the unsteadiness of the seepage flow fteld. There fore, the position of a moving phreatic line can only be obtained by means of sketching transient steady flow nets until they coincide with the position of the phreatic line from the calculation of the piezometeric level line that has been corrected for time lag. Same examples are given to show the characteristics of the transient flow net. Finally, some suqqestions are made about the observation of seepage pressure.
出处
《大坝观测与土工测试》
北大核心
1990年第3期10-16,共7页
Dam Observation and Geotechnical Tests
