Discussion

Mr M. Bolton opened the questions at the end of the first session by addressing a question to Dr R. Jewell. Earlier, in his talk Dr Jewell had stated that well-established earth pressure coefficients, such as those of Caquot et al (1973), could be used directly in the context of steep slopes by taking the wall roughness, 8w, to be (90 - p), where was the angle of the slope, but for slope angles less than p < (90 — <|>) Dr Jewell had had to perform his own analyses. In Dr Jewell's analyses the gross effect of the reinforcement layers had been represented by a single horizontal force applied externally to the front face. Mr Bolton questioned the correctness in such analyses of applying a force to a surface at an inclination in excess of the angle of friction. Mr Bolton, addressing Mr Greenwood, also questioned the suitability of building slopes with non-wrap-around facing, at slope angles in excess of <)>', in view of potential local instability at the front face. He also requested a definition from any of the speakers as to what constituted a 'steep slope'.