(Solved): 6.C. 1 Since laboratory or field experiments are generally expensive and time con- suming, geotechni ...
6.C. 1 Since laboratory or field experiments are generally expensive and time con- suming, geotechnical engineers often have to rely on empirical relationships to predict design parameters. Section 6.6 presents such relationships for pre- dicting optimum moisture content and maximum dry unit weight. Let us use some of these equations and compare our results with known experimental data. The following table presents the results from laboratory compaction tests conducted on a wide range of fine-grained soils using various compactive efforts
(E). Based on the soil data given in the table, determine the optimum moisture content and maximum dry unit weight using the empirical relation- ships presented in Section 6.6. a. Use the Osman et al. (2008) method [Eqs. (6.15) through (6.18)]. b. Use the Gurtug and Sridharan (2004) method [Eqs. (6.13) and (6.14)]. c. Use the Matteo et al. (2009) method [Eqs. (6.19) and (6.20)]. d. Plot the calculated
w_(opt )against the experimental
w_(opt ), and the calcu- lated
\gamma _(d(max))with the experimental
\gamma _(d(max)). Draw a
45\deg line of equality on each plot. e. Comment on the predictive capabilities of various methods. What can you say about the inherent nature of empirical models? Note:
^(a)Tschebotarioff (1951)
^(b)Modified Proctor test
^()S Standard Proctor test
^(d)Standard Proctor mold and hammer; drop: 305 mm ; layers: 3; blows/layer: 15
^(e )Modified Proctor mold and hammer; drop: 457 mm ; layers: 5; blows/layer: 26
^(f)Modified Proctor mold; standard Proctor hammer; drop: 305 mm ; layers: 3; blows/layer: 25
