ASTM D6391-11 (R2020) PDF Download

A cased borehole technique is described in ASTM D6391-11 (R2020) as a way to measure the hydraulic conductivity of porous materials. For evaluating the hydraulic conductivity of fine-grained clayey soils in the low range, between 110-7 m/s and 110-11 m/s, the test method is particularly well suited.

This standard is helpful for monitoring the liquid flow through soil hydraulic barriers, including seepage blankets, canal and reservoir liners, compacted clay barriers in waste containment facilities, and altered soil liners. The thickness of the unit being tested must be at least 600 mm, or 800 mm if the material is underlain by a substance that is much less permeable.

The soil layer being tested must have enough cohesiveness, according to the test technique, for it to remain open while the borehole is being dug. A reasonably significant volume of soil can be used to measure the infiltration rate, which can yield results that are more accurate than those from studies on smaller amounts of soil. When the soil layer being tested has a homogeneous distribution of pore space and hydraulic conductivity with well-defined upper and lower boundary conditions, the data acquired from this test method are most helpful.

According to the standard, temperature variations can cause mistakes in flow measurements, especially in soils with hydraulic conductivities of 5–10 m/s or less. A temperature effect gauge (TEG) is used to take temperature impacts and other environmental disturbances into consideration.

It is crucial to remember that the accuracy of the findings generated by this standard depends on the skill of the individuals conducting the test and the suitability of the facilities and equipment employed. Compliance with ASTM Practice D3740, which assesses elements including staff expertise and equipment appropriateness, does not ensure accurate outcomes.