Homework 3 (pdf) - Geotechnical Earthquake Engineering

(d) The deep, dense gravelly sands are underlain by additional Old Bay Clays (CH/CL). These
are even older, and so are even stiffer and stronger. Treat these as an extension of the Old
Bay Clay unit from above the gravelly sands. Again, remember that we also have V s data,
but that SASW does not work well in the “shadow” just below a stiffer layer (e.g. the
gravelly sands), and that we are very deep for SASW!
(e) Our site investigations (both borings and testing, as well as SASW) provided essentially no
useful, quantitive data regarding the weathered shale and the harder, more intact sandstone
“bedrock” underlying the deep clays. Refer to Figures 1 and 2. Dickenson assigned Vs =
730 m/sec to the weathered shale, and treated the sandstone as an elastic halfspace with Vs =
1,220 m/sec. Do these values seem reasonable? Now, feel free to choose your own.
4. Finally, prepare a full proposed site profile, divided into sub-layers, for your response
analyses. Show the proposed profile of V s vs. depth, and provide figures showing your
proposed relationships for G/Gmax vs. γ and B vs. γ for each soil and/or “rock” unit,
including the base “rock”.