Seismic soil pressure of cohesive backfill

Followed the derivation of the well known M-O method, a set of calculation formulas for seismic active and passive Soil pressure of cohesive backfill on retaining structure are cleared up and derived in this paper. The formulas take the cohesion of the backfill, a uniformly distributed load on the ground surface of the backfill and the gradient of the surface into account. For practical purpose, two sets of simplified formulas are also presented. In the simplification process, the gamma + c pattern is adopted and the advantages of the M-O procedure are preserved partly, while the manner of Seed-Whitman's simplification is referred in the simplified process. In order to illustrate the applicability and reliability of the simplified formulas, the result of the first set of simplified formulas is compared with those results from some currently used formulas, the result of the second set of simplified formulas with those from the formula in the Chinese Code of Earthquake Resistant Design for Water Transport Engineering from real examples.