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Application of coupled stress-flow analysis to the field problem
2.6A investigated: the phreatic surface should be accurately established; and consolidated undrained triaxial tests with pore pressure measurement should be undertaken, sufficiently slowly to permit pore pressure equalisation. 872252 Failure of rock slope at Powrie Brae, Dundee. Technical note Reid, W M Proc Symposium on Failures in Earthworks, London, 6-7 Atarch 1985 P454-457. Publ London." Thomas Telford, 1985 A large planar rock slip occurred during the realignment of the A929 road in Scotland. The rock mass. micaceous siltstones and sandstones, had an angle of friction for rock to rock contact of 24 deg, but the presence of thin clay layers on some bedding planes led to a water pressure initiated failure along a bedding plane at 13 deg to the horizontal. The most economical l`orm of remedial work proved to be the installation of shear dowels perpendicular to the bedding plane. 872253 Application of coupled stress-flow analysis to the field problem Ohtsu, H; Kamemura, K Proc 5th International Conference on Numerical Afethods in Geomechanics, Nagoya. 1-5 April 1985 VI, P597-604. Publ Rotterdam: A. A. Balkema, 1985 The applicability of coupled stress-flow analysis for problems taking into account groundwater flow is referred to, and the following are discussed: (1) boundary conditions of excavated surfaces in these circumstances; (2) mechanism of progressive failure in the stability problems of a large slope proposed by Bjerrum et al; and (3) interpretation of in situ pore pressure data measured around a shaft in tertiary mudstone.
Earth retaining structures See also: 872177 872254 Performance of a deep cofferdam around a collapsed tunnel in glacial clays Goldsworthy, M H Ground Engng V19, N7, Oct 1986. P14-18 A sheet pile cofferdam has been excavated to over 20m below ground level in order to reinstate a collapsed canal tunnel. The ground at the site is firm clayey till becoming stiff with depth, with horizons of stiff lacustrine clay. During excavation, strut loads were monitored using vibrating wire gauges and displacements of the ground adjacent to the sheet piles were observed using an inclinometer. The loads developed in the lower supports during the later stages of the excavation were considerably less than those which would be calculated using the traditional approaches. It is suggested that consideration of the horizontal stress field existing prior to excavation leads to an explanation of the bottom strut observations. 872255 Solution of the problem of a passive wall in sand described by the critical state model, by use of the method of stress characteristics (In French) Hovan, J M; Graham, J Rev Fr Geotech N36, 1986. P5-16 The two dimensional problem of a retaining wall against sand has been studied by the method of stress characteristics. The sand is described by the critical state model, which takes account of local stress variation in the failure zone, placement density and compressibility of the sand, and the transition of the sand from softening to hardening as stress increases. ~
Results suggest a log-linear relation between earth pressure and wall height, dependent on the properties of the sand. Results are compared with available published work. 872256 Effects of vertical wall movements on lateral earth pressure Moore, P J; Choong, Y T Trans lnst Engrs Australia Civ Engng VCE28, N3, July 1986, P250-255 Pressure cells set into the back of the wall were used to record the earth pressure developed/'or a moving wall, for which the dominant movement was vertical. Dry sand was the backfill material. Lateral pressure increased following upward wall movement and decreased following downward movement. A small lateral movement component, towards the backfill on the upstroke, was evident. Magnitudes of peak lateral pressure were dependent on the magnitude of upward wall movement and number of cycles of movement. The variation in peak pressure with movement was related to the development of wall friction. Approximate agreement was obtained between calculated and observed performance. 872257 Instrumentation for deep excavation of high-rise buildings Chen, H M; Chung, S T Proc 8th Southeast Asian Geotechnical Conference, Kuala Lumpur, Malaysia, 11-15 March 1985 VI, P2/66-75. Publ Kuala Lumpur: Organising Committee, 1986 In Taipei, Taiwan, basement excavation in soft ground, mainly silty clay and loose silty sand, with a high water table, has led to damage to neighbouring infrastructure. Three case studies where braced diaphragm walls were used and the excavations were monitored are described. Instrumentation included inclinometers, piezometers, heave stakes, settlement points, load cells and strut strain gauges. The field monitoring data are presented and performance of the retaining structures discussed.
Construction methods 872258 Advanced surface mining technology - the Warren Centre project overview Atkinson, T Aust J Coal Min Technol Res NI2, 1986, P29-37 As Australian reserves of fiat dip, shallow depth, surface mineable coal become depleted, it will be necessary to exploit deposits in more complex geological settings, with deeper overburden, steeper dip, greater groundwater problems, increased geotechnical difficulties, and possibly less competent materials. An in-depth study is being made of the surface mining industry, to examine future needs in terms of existing systems and anticipated innovative systems. These ideas are considered in realistic geological settings. Areas where research and development are essential are identified.
Influence of dynamic loads 872259 Simplified seismic analysis of rigid base liquid storage tanks under vertical excitation with soil-structure interaction Haroun, M A; Abdel-Hafiz, E A Soil Dynam Earthq Engng ~ , N4, Oct 1986, P217-225 A simplified method has been developed for the evaluation of the dynamic response of an elastic tank on a rigid base, subjected to vertical excitation, which takes into account shell-
1986 Pergamon Journals Ltd. Reproduction not permitted
Earth retaining structures See also: 872177 872254 Performance of a deep cofferdam around a collapsed tunnel in glacial clays Goldsworthy, M H Ground Engng V19, N7, Oct 1986. P14-18 A sheet pile cofferdam has been excavated to over 20m below ground level in order to reinstate a collapsed canal tunnel. The ground at the site is firm clayey till becoming stiff with depth, with horizons of stiff lacustrine clay. During excavation, strut loads were monitored using vibrating wire gauges and displacements of the ground adjacent to the sheet piles were observed using an inclinometer. The loads developed in the lower supports during the later stages of the excavation were considerably less than those which would be calculated using the traditional approaches. It is suggested that consideration of the horizontal stress field existing prior to excavation leads to an explanation of the bottom strut observations. 872255 Solution of the problem of a passive wall in sand described by the critical state model, by use of the method of stress characteristics (In French) Hovan, J M; Graham, J Rev Fr Geotech N36, 1986. P5-16 The two dimensional problem of a retaining wall against sand has been studied by the method of stress characteristics. The sand is described by the critical state model, which takes account of local stress variation in the failure zone, placement density and compressibility of the sand, and the transition of the sand from softening to hardening as stress increases. ~
Results suggest a log-linear relation between earth pressure and wall height, dependent on the properties of the sand. Results are compared with available published work. 872256 Effects of vertical wall movements on lateral earth pressure Moore, P J; Choong, Y T Trans lnst Engrs Australia Civ Engng VCE28, N3, July 1986, P250-255 Pressure cells set into the back of the wall were used to record the earth pressure developed/'or a moving wall, for which the dominant movement was vertical. Dry sand was the backfill material. Lateral pressure increased following upward wall movement and decreased following downward movement. A small lateral movement component, towards the backfill on the upstroke, was evident. Magnitudes of peak lateral pressure were dependent on the magnitude of upward wall movement and number of cycles of movement. The variation in peak pressure with movement was related to the development of wall friction. Approximate agreement was obtained between calculated and observed performance. 872257 Instrumentation for deep excavation of high-rise buildings Chen, H M; Chung, S T Proc 8th Southeast Asian Geotechnical Conference, Kuala Lumpur, Malaysia, 11-15 March 1985 VI, P2/66-75. Publ Kuala Lumpur: Organising Committee, 1986 In Taipei, Taiwan, basement excavation in soft ground, mainly silty clay and loose silty sand, with a high water table, has led to damage to neighbouring infrastructure. Three case studies where braced diaphragm walls were used and the excavations were monitored are described. Instrumentation included inclinometers, piezometers, heave stakes, settlement points, load cells and strut strain gauges. The field monitoring data are presented and performance of the retaining structures discussed.
Construction methods 872258 Advanced surface mining technology - the Warren Centre project overview Atkinson, T Aust J Coal Min Technol Res NI2, 1986, P29-37 As Australian reserves of fiat dip, shallow depth, surface mineable coal become depleted, it will be necessary to exploit deposits in more complex geological settings, with deeper overburden, steeper dip, greater groundwater problems, increased geotechnical difficulties, and possibly less competent materials. An in-depth study is being made of the surface mining industry, to examine future needs in terms of existing systems and anticipated innovative systems. These ideas are considered in realistic geological settings. Areas where research and development are essential are identified.
Influence of dynamic loads 872259 Simplified seismic analysis of rigid base liquid storage tanks under vertical excitation with soil-structure interaction Haroun, M A; Abdel-Hafiz, E A Soil Dynam Earthq Engng ~ , N4, Oct 1986, P217-225 A simplified method has been developed for the evaluation of the dynamic response of an elastic tank on a rigid base, subjected to vertical excitation, which takes into account shell-
1986 Pergamon Journals Ltd. Reproduction not permitted