The figure on the right shows compression curves from several tests on Boston Blue clay sampled...
The figure on the right shows compression curves from several tests on Boston Blue clay sampled from the same depth. These data don't come from oedometer tests, but are derived instead from another type of test (CRS test) which 1.25 1.20 1.10 1.05 1.00 continuous095 0.90 0.85 0.80 0.75 0.70 0.65 provides a compression curve Based on the data shown, a) Estimate the value of the compression index (slope of the virgin compression line); b) Estimate the value of the recompression index from the unload portion of the Shaded area indicales range of triax results with no radial 100 1000 o've (kPa) curve c) Estimate the corresponding parameters in the strain-log effective stress space: the compression ratio (CR, which your book terms Cce) and the recompression ratio (RR, which your book terms Cre) d) Provide a first "crude estimate of the in situ preconsolidation stress of the soil at the location where the samples used to obtain the curve were obtained. You need not use the Casagrande method (which you will learn in lab). Instead simply estimate by eye e) If the effective stress at the location where the soil was sampled is 75 kPa, what is the OCR of the soil at that location?