13 February 1973 at 5.15 p.m.
Geotechnical problems of deep excavation.
By M. J. Tomlinson
The paper described the various problems encountered in deep excavations for foundations, access shafts and ship building docks. These problems included the stability of slopes in soil and rock, erosion of slopes due to inflow of ground water, boiling and heave of the base of excavations, and the inward yielding of the supported sides of excavations. Methods of estimating the required slopes of excavations for short-term stability were discussed, and an account was given of methods of ground water control. The method included well-pointing, bored well installations, grouted barriers, diaphragm walls and sheet piling with examples of the various methods. The inward yielding of the sides of deep excavations were discussed in relation to methods of support by timbering, sheet piling and diaphragm wall construction in various soil and rock conditions. Comparisons were given of yielding of strutted and anchored support systems. The paper was illustrated by case histories of shaft excavations for the foundations of high buildings and nuclear power stations, the stability of excavated slopes for the Harland & Wolff ship building dock at Belfast, ground water control in dock construction on various projects in the United Kingdom and some recent basement excavations.
21 March 1973 at 5.30 p.m.
Joint Meeting with the British Geotechnical Society
Geological and geotechnical problems of engineering works in progress.
Geological Aspects of Hydro-Power Developments in Colombia.
By R. E. Goodman
A current evaluation of potential power development