Citation

Hennes RG, Hawkins SE, McCoy EL. Highw. Res. Board bull. 1959; 216: 17-30.

Copyright

(Copyright © 1959, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

Generally, attempts to increase the factor of safety of an earth slope involve either drainage or excavation. The object of drainage is a lowering of the water table, with an accompanying reduction in the magnitude of favorable forces. In the present paper several graphs are presented which enable the engineer to estimate the amount of drainage necessary to achieve a desired factor of safety. These graphs yield safety factors corresponding to various levels of water table in an earth mass where the failure plane would approximate a swedish arc located in a clay bank underlain by a permeable stratum. An alternative procedure improves stability by unloading the slope. It is shown that flattening the slope is much less effective than benching per unit of excavation. Graphs are presented which plot factor of safety against quantity of excavation for both benching and slope reduction.