USING AN AUTOMATED ROWE CELL FOR CONSTANT RATE OF STRAIN CONSOLIDATION TESTING

The paper describes the automation and calibration of a hydraulic Rowe consolidation cell that tests 151-mm-diameter by 60-mm-high specimens . The associated measurement instrumentation for the cell and specimen preparation procedures are also described. The cell was used to perfo rm a set of one-dimensional constant rate of strain (CRS) tests at two vertical strain rates, 0.1 and 1%/h. The nonlinear CRS theory of Wiss a et al. (1971) is presented, including methods for interpreting test results at higher strain rates. The results from the Rowe cell tests c onducted on resedimented Boston Blue Clay am compared to those from mo re conventional incremental loading (IL) oedometer tests (63.5-mm-diam eter by 23-mm-high specimens). For both the 0.1%/h tests (in which neg ligible excess pore pressure was generated at the undrained specimen b ase) and the 1%/h tests, the compression curves compare well with the baseline IL oedometer test curves. Values of preconsolidation pressure , sigma(p), averaged 94.0 kPa in the Rowe tests and 94.5 kPa in the IL oedometer tests. The compression ratios, CR = Delta epsilon(v)/Delta log sigma'(v), in the virgin compression range were slightly lower in the Rowe cell tests (average 0.156 versus an average CR = 0.173 in the IL oedometer tests), which may be due to different testing conditions (e.g., back pressure in the Rowe cell) or the larger Rowe cell specim en. The coefficient of consolidation and hydraulic conductivity values computed from the Rowe cell tests are essentially identical with rega rd to stress level to the IL oedometer tests. The automated Rowe cell data indicate that the device offers a reliable and potentially rapid method for determining consolidation parameters, including hydraulic c onductivity.