Seminar - Andrew De Ambrosis - Design of shotcrete facing in soil nailed excavations

Wednesday, July 19, 2000, 3 - 4 pm
Civil Engineering Lecture Room 3

Abstract

Ease of construction, flexibility of design and economic competitiveness
have meant that soil nailed excavations have become increasingly accepted
as a feasible means of excavation support. However, despite there being a
large pool of published data describing actual walls constructed and at least
three widely accepted design codes, (Japanese design code (JHPC 1987),
recommendations of Clouterre (FHWA 1993), British standards (BS
8006:1995)), there still remains much to be learned regarding working
stresses within the reinforcement system. In particular, the earth pressures
experienced by the shotcrete facing are largely unquantified.

This talk presents some interesting aspects arising from investigations into
the soil nailed earth retaining technique. Soil nailed support systems are
described in general, and a review made of the existing methods of facing
design. The importance of properly modelling the excavation process is
highlighted, with particular reference to the impact on facing response. In
conclusion, various indicators of possible facing response, which are not
considered by the existing design methods, are identified and their
importance discussed.