71A 892163 Self-boring pressuremeter testing in London clay O'Brien, A S; Newman, R L
Proc 24th Annual Conference of the Engineering Group of the Geological Society, Field Testing in Engineering Geology, Sunderland, 4-8 Sept 1988 P37-69. Publ Sunderland: Sunderland Polytechnic, 1988 Self-boring pressuremeter tests were performed in London clay 13m and 120m from a tunnel. In analysis of the data, the effects of disturbance and strain arm characteristics were considered. Instrument characteristics were shown to significantly affect the data, so several approaches were used to determine in situ lateral total stress: inspection methods, ratio of shear modulus to mean effective stress, and curve fitting methods. Pressuremeter test data clearly show that construction of the tunnel has reduced the in situ lateral total stress. Profiles of earth pressure coefficient at rest were also determined. 892164 In situ lateral stress assessment in London clay with the self boring pressuremeter Corke, D J
Proe 24th Annual Conference of the Engineering Group of the Geological Society, Field Testing in Engineering Geology, Sunderland, 4-8 Sept 1988 P71-85. Publ Sunderland. Sunderland Polytechnic, 1988
injection, cone penetration, and laboratory tests carried out. Factors relevant to tunnelling were evaluated. Mixed face conditions of weathered tuff, boulders or layers or masses of basalt, sands, sediments, and coral reef remnants were found over one third of the length. Results indicate that accurate prediction requires high quality site investigation.
Remote sensing and photographic techniques 892167 Remote sensing of vegetation - a promising exploration tool Hodcroft, A J T; Moore, J M
Min Mag Oct 1988, P274-279 Vegetation is commonly affected by changes in underlying rock type or metals and hydrocarbons in the soil. Canopy texture and spectral alterations can be detected by modern sensitive remote sensing devices. Symptoms in the non-visible spectrum are described, and available systems for their detection, aerial photography, radar imaging, and Landsat multispectral scanning, are illustrated. Practical aspects of such remote sensing are examined.
Structural and geotechnical mapping See also: 892128
Results from pressuremeter tests on 4 London clay sites are presented. To check consistency, the normalised parameters, shear strength/limit pressure and in situ total lateral stress/limit pressure, were determined,and found to be generally consistent. Reasons for measured lateral pressures being higher than those expected from published information are discussed.
892168 Seismic microzoning on soil liquefaction potential based on geomorphological land classification Kotoda, K; Wakamatsu, K; Midorikawa, S
892165 Some recent in-situ stress testing experience on strong clays and weak rocks in Britain Stevenson, M C; Martin, J H; Squire, P O Proc 24th Annual Conference of the Engineering Group of the
A hazard zoning procedure is described. For each geomorphological unit, critical peak ground velocity (cpgv) for liquefaction has been evaluated using data from about 250 sites during 19 earthquakes. Cpgvs at sites with the same geomorphological units are very close. Combining land classification and isoseismal data representing distribution of peak ground velocity, seismic microzoning for liquefaction can be easily achieved.
Geological Society, Field Testing in Engineering Geology, Sunderland, 4-8 Sept 1988 P87-106. Publ Sunderland." Sunderland Polytechnic, 1988 Pressuremeter testing was carried out at 2 sites in hard clays and weak mudstones. Self boring pressuremeter tests were mainly used, but high pressure dilatometers were necessary below 20m. The effect of geological conditions on stress history is considered. The tests permit classification of ground conditions into ranges related to geological stress history, giving a guide to mean magnitude and variability of in situ stress for civil engineering design.
Site Investigation and Field Observation
Soils Found V28, N2, June 1988, P127-143
892169 Discontinuity mapping - a comparison between line and area mapping Mathis, J I
Proc 6th International Conference on Rock Mechanics, Montreal, 30 Aug-lO Sept 1987 V2, P l l I I - I I I 4 . Publ Rotterdam: A A Balkema, 1987 Time and access for discontinuity mapping is often limited for underground excavations. Conventional scanline mapping is time consuming. Mapping of various tunnels for the Forsmark repository, Sweden, in granitic and gneissic rocks, was undertaken using scanline and cell mapping, where joint sets in a 4mx4m window on a tunnel wall were mapped. Data reduction techniques are described, and joint length and joint set orientations illustrated. The area (cell) technique is seen to be viable.
See also: 892319 892166 Tunnelling investigation in a highly complex marine-volcanic sequence, Honolulu, Hawaii, U.S.A. Kwong, J K P; Mahar, J W; Cording, E J
Proc Tunnelling '88, London, 18-21 April 1988 P159-173. Publ London: IMM, 1988 Multiphase investigations along the 1.6km alignment of a tunnel is described. 41 borings and 2 large observation shafts were made, 39 piezometers installed, and field permeability, grout
892170 Alternative approach to the modelling of deformed stratiform and stratabound deposits Sides, E J
Proc APCOM 87, Johannesburg, 19-23 Oct 1987 V2, P187198. Publ Johannesburg: SAIMM, 1987 Folded stratiform and stratabound deposits are problematical for orebody modelling and reserve estimation because of difficulties in transforming samples and blocks into their correct relative positions prior to deformation. An approach is taken
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