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Permeability of Grout Seals Surrounding Thermoplastic Well Casing
Author(s) -
Kurt Carl E.,
Johnson Roy C.
Publication year - 1982
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1982.tb02761.x
Subject(s) - grout , permeability (electromagnetism) , casing , materials science , bentonite , composite material , geotechnical engineering , cement , geology , chemistry , petroleum engineering , biochemistry , membrane
An experimental test program was conducted to measure the longitudinal permeability of a grouted thermoplastic water well casing system. A neat cement grout, with and without calcium chloride or bentonite admixtures, was placed in the annulus of a simulated well. Test pressure and specimen configuration was shown to influence the measured coefficient of permeability. A neat grout with a water/cement ratio of 2.0 had a much higher permeability coefficient than the same grout with a water/cement ratio of 0.46. Once the bond line between the grout and casing was broken, the permeability of the system was generally higher than for the initial test. Specimens with a bell coupling included had a slightly higher permeability than specimens with straight pieces of casing. The effect on permeability of the admixtures in the grout was not conclusive. However, the addition of a bentonite slurry to the test water was observed to decrease the permeability coefficient when tested under low pressure. The permeability coefficient of the basic neat grout casing system ranged from 20 – 100 × 10 −5 cm/sec at low test pressure. It was concluded that the casing has an impact on the longitudinal permeability of the system since the coefficients of permeability measured were significantly higher than other published values. However, the coefficients of permeability measured were in the range of soils with low permeability such as silts.