《Journal of Hydrologic Engineering》杂志刊登“粗砂砾的瞬态气动入渗试验”

作者：A. I. Judge,D. W. Ostendorf,D. J. DeGroot,V. A. Zlotnik

刊物：《Journal of Hydrologic Engineering》，2013年3月13日印刷

摘要：本文提出了使用一种新渗透仪来做室内渗透试验的方法，其中所用的材料是渗透系数从0.1到1m/s之间变化的砾石。并将一个小直径立管连接到一个大圆筒，其持有的粗粒试件浸泡在水中。对立管中的自由水面上释放了气动压力，使得立管中的水面产生缺少阻尼的震荡反应，这也类似于监测井中的原位微水试验响应。对装有和不装有试样的渗透仪的试验测量渗透系数，为了校准渗透仪和试样的渗透系数，用一个封闭的模型来分析测量得到的震荡水头数据。所校准的立管中压力水头值的平均模型误差大约是初始位移2cm的5%左右。通过考虑重复试验、不同试件长度的试验以及不同时间间隔的试验对渗透系数进行校准，验证了利用一个试验即可反映渗透性的渗透系数。均匀的大理石有已知的比表面积，由于Kozeny-Carman 方程提供了在大理石测量值5%以内的渗透系数的值，且其考虑实验材料的比表面积，可以用来与上述试验进行比较。通过对于每个试样进行了不同的试验，结果表明，大部分渗透系数与平均值相差均的10%以内，渗透系数大于1m/s时与平均值相差在10%到20%之间。

A Pneumatic Permeameter for Transient Tests on Coarse Gravel

Authors: A. I. Judge,D. W. Ostendorf,D. J. DeGroot,V. A. Zlotnik

Journal: Journal of Hydrologic Engineering, Published: 13 March 2013

Abstract: A new permeameter is proposed for performing laboratory hydraulic conductivity tests on gravels with hydraulic conductivity values ranging from 0.1 to 1 m/s. A small diameter riser is connected to a large diameter cylinder, which holds the coarse-grained specimen saturated in a water bath. The release of pneumatic pressure applied to the free surface in the riser induces an underdamped oscillatory response of the water level in the riser, similar to an underdamped in situ slug test response in monitoring wells. A closed form model used to analyze the measured oscillatory hydraulic head data to calibrate the minor losses in the permeameter and the hydraulic conductivity of the specimen by performing tests without and with a specimen. The average model error of calibrated pressure head values in the riser for the tests considered is on the order of 5% of the initial displacement of about 2 cm. The hydraulic conductivity values are calibrated considering replicate tests, tests of different specimen lengths, and different time periods within a test to verify that the results reflect the hydraulic conductivity of the specimen alone. The Kozeny-Carman equation which considers the specific surface area of the tested material gave a hydraulic conductivity value within 5% of the measured value for the marbles, which is a good comparison because the uniform marbles have a known specific surface area. For all the various tests performed on each specimen, most of the hydraulic conductivity values were within 10% of the average, while the specimens with hydraulic conductivity greater than 1 m/s were within 10 to 20% of the average.

原文链接：http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29HE.1943-5584.0000813