EN Bromhead, MSc, DIC, BSc, CEng, MICE. This paper was first published in GE’s July 1979 edition.
The hitherto expensive and time-consuming nature of ring shear tests to determine the residual strength of soils has prevented the test from becoming a routine procedure in commercial laboratories. This has had the result that the ideal “three-pronged attack” on landslip problems by
(a) back analysis,
(b) ring shear tests on representative strata, and
(c) direct shear tests on actual slip surfaces,
is rarely fully developed. Since a number of studies have shown that the ring shear tests may possibly provide the lower bound strengths in any investigation, this omission is of concern.
However, ring shear testing cannot become a routine procedure outside the research laboratory until a simple, robust, inexpensive apparatus which has a fairly large potential through-put of tests in the working week is developed. This Paper describes such a device, which has recently been built and evaluated at the Schoal of Civil Engineering, Kingston Polytechnic and which in its fully developed form is now available commercially.