UPDATE 2014-01-14: The attached .zip file now contains a Mathcad Prime 3.0 worksheet (.mcdx) and—for those of you who are still using earlier verisions of Mathcad—an Adobe Acrobat printout (.pdf) of the worksheet so can see how it is put together.
The purpose of this worksheet is to take the lateral earth pressures provided in a typical geotechnical report and calculate several related soil parameters, some of which may not be provided in the report. This worksheet is based on the Rankine Theory of lateral earth pressure.
I originally created this worksheet to check the data in a geotechnical report I had received because the reported passive pressure was quite a bit less than I was used to seeing. This was back when Mathcad 5.0 was the latest and greatest. When I calculated the unit weight of soil using the active and passive pressures, it was considerably less than the reported value. Working backwards, I then calculated the passive pressure using the active pressure and the unit weight of soil. What I found was a simple typo in the geotechnical report: the passive pressure should have been reported as 350 pcf, not 250 pcf. The values used in this worksheet are the corrected values from that old geotechnial report.