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Geotechnical classification of Ivory Coast soils (In French)
70A investigated. A liquefaction prediction method based on the CPT has been developed. A simplified chart showing variation in normalised critical qc value with depth for different earthquake magnitudes, maximum surface accelerations, and groundwater levels is presented. The method was evaluated using field data. 892155 Sorptivity and conductivity measurement: note Parlange, J Y; Haverkamp, R; Rose, C W; Phillips, I Soil Sci V145, N5, May 1988, P385-388 The in situ measurement of sorptivity with infiltrometers using the fallinghead method is fundamental in soil physics. The theory underlying the method is re-examined, showing small but significant corrections have to be made to previous results. The new theory is used to analyse experimental observations of infiltration into a sandy soil. The results are accurate enough to demonstrate the dependence of sorptivity and conductivity on density variations of about 5%.
In Situ Stress Measurement of in situ stress 892159 Determination of horizontal geostatic stress in clay with selfbored pressuremeter Jefferies, M G Can Geotech J V25, N3, Aug 1988, P559-573 Computer aided modelling is used to show that horizontal geostatic stress in clay may be determined from self boring pressuremeter data interpreted using an extended version of Gibson-Anderson theory which includes unloading. A closed form solution for the complete SBP test in clay is developed. It is shown that the value of horizontal geostatic stress derived is insensitive to disturbance during self boring and deficiencies in the elastic-plastic characterisation of clay strength. The method is illustrated using existing data for Beaufort Shelf clay.
Identification and classification 892156 Using the effective contact angle and water drop penetration time for classification of water repellancy in dune soils. Short communication Wessel, A T Earth Surf Process Land VI3. N6. Sept 1988. P555-561 Sandy soils arc often water repellent, and this may lead to surface runoff and erosion of slopes. Water repellancy can be classified by the contact angle, which is hard to measure, or by water drop penetration time, which is simpler to determine, more directly related to erosion hazard, and allows a more flexible classification scheme. Experimental measurements show close correlation for the two classification parameters for dune soils from the Netherlands coast. 892157 Expert systems for classification of rock masses Qing Zhang; Yuan-bin Mo; Shen-feng Tian Key Questions in Rock Mechanics: Proc 29th US Symposium, Minneapolis, 13-15 June 1988 P283-288. Publ Rotterdam: A A Balkema, 1988 A prototype expert system to run on IBM compatible PCs is described. The classification system of Gu (1976), which emphasises macro discontinuities, and in which all parameters are qualitative is used. Six main parameters were inducted from Gu's classification: effect of regional tectonic deformation; rock property; average thickness; development of the structural plane: extension of the structural plane; and compressive strength. Reasoning in the presence of uncertainty using fuzzy set theory, and control strategy are discussed.
892160 Effect of borehole deviation on breakout orientations Mastin, L J Geophys Res V93. NB8, Aug 1988, P9187-9195 For vertical wellbores in regions of vertical principal stress, breakout tends to appear in the direction of least horizontal principal stress. An elastic solution for stress at the borehole wall is used to analyse rotation of borehole breakout orientation as the borehole deviates from the direction of the vertical principal stress. Calculated orientations depend on the type of faulting regime in which the well was drilled, borehole deviation from vertical, angle between horizontal projection of the borehole axis and direction of least horizontal principal stresses, and relative values of the principal stresses. Breakout orientation may be used to infer stress direction. 892161 Bolmen project: rock stress measurements using hydraulic fracturing and overcoring techniques Bjarnason, B; Leijon, B; Stephansson, O Tunnlg Underground Space Technol V3, N3, 1988. P305-316 Stress measurements were made at two locations along the Bolmen tunnel, Sweden, using both overcoring and hydraulic fracturing techniques. The work was intended to determine far field stress in the region, stress state close to the tunnel, and any anomalies associated with the Staverhult Line. Because of the small stress magnitudes and difficulties associated with the relatively fractured rock mass, considerable experimental uncertainty was attached to the results. It was not possible to determine principal stress directions from the data.
892158 Geotechnical classification of Ivory Coast soils (In French) Cougny. G Proc Ninth Regional Conference for Africa on Soil Mechanics and Foundation Engineering, Lagos, Sept 1987 VI, P81-90. Publ Rotterdam: A A Balkema, 1987
892162 Hydraulic fracturing stress measurements at two sites in Leicestershire, United Kingdom Stewart, I; Monaghan, B G Proc CARE 88 (Conference on Applied Rock Engineering), Newcastle, 6-8 January 1988 P221-233. Publ London: IMM, 1988
Both deposited and residual soils occur in Ivory Coast. Traditional classification systems, developed largely for deposited soils, are inadequate for residual soils, so the LBTP-1986 system has been developed. This classification, based on both genetic and geotechnical identification using traditional laboratory tests, is outlined.
The equipment and techniques used in measuring in situ stress by means of hydraulic fracture are described. The method is illustrated for 2 boreholes, one in sandstone, the other in siliceous tufts. The principal horizontal stress is determined for each. The influence of local geological evidence of stressrelated events on the in situ stress is discussed.
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1989 Pergamon Press pie. Reproduction not permitted
In Situ Stress Measurement of in situ stress 892159 Determination of horizontal geostatic stress in clay with selfbored pressuremeter Jefferies, M G Can Geotech J V25, N3, Aug 1988, P559-573 Computer aided modelling is used to show that horizontal geostatic stress in clay may be determined from self boring pressuremeter data interpreted using an extended version of Gibson-Anderson theory which includes unloading. A closed form solution for the complete SBP test in clay is developed. It is shown that the value of horizontal geostatic stress derived is insensitive to disturbance during self boring and deficiencies in the elastic-plastic characterisation of clay strength. The method is illustrated using existing data for Beaufort Shelf clay.
Identification and classification 892156 Using the effective contact angle and water drop penetration time for classification of water repellancy in dune soils. Short communication Wessel, A T Earth Surf Process Land VI3. N6. Sept 1988. P555-561 Sandy soils arc often water repellent, and this may lead to surface runoff and erosion of slopes. Water repellancy can be classified by the contact angle, which is hard to measure, or by water drop penetration time, which is simpler to determine, more directly related to erosion hazard, and allows a more flexible classification scheme. Experimental measurements show close correlation for the two classification parameters for dune soils from the Netherlands coast. 892157 Expert systems for classification of rock masses Qing Zhang; Yuan-bin Mo; Shen-feng Tian Key Questions in Rock Mechanics: Proc 29th US Symposium, Minneapolis, 13-15 June 1988 P283-288. Publ Rotterdam: A A Balkema, 1988 A prototype expert system to run on IBM compatible PCs is described. The classification system of Gu (1976), which emphasises macro discontinuities, and in which all parameters are qualitative is used. Six main parameters were inducted from Gu's classification: effect of regional tectonic deformation; rock property; average thickness; development of the structural plane: extension of the structural plane; and compressive strength. Reasoning in the presence of uncertainty using fuzzy set theory, and control strategy are discussed.
892160 Effect of borehole deviation on breakout orientations Mastin, L J Geophys Res V93. NB8, Aug 1988, P9187-9195 For vertical wellbores in regions of vertical principal stress, breakout tends to appear in the direction of least horizontal principal stress. An elastic solution for stress at the borehole wall is used to analyse rotation of borehole breakout orientation as the borehole deviates from the direction of the vertical principal stress. Calculated orientations depend on the type of faulting regime in which the well was drilled, borehole deviation from vertical, angle between horizontal projection of the borehole axis and direction of least horizontal principal stresses, and relative values of the principal stresses. Breakout orientation may be used to infer stress direction. 892161 Bolmen project: rock stress measurements using hydraulic fracturing and overcoring techniques Bjarnason, B; Leijon, B; Stephansson, O Tunnlg Underground Space Technol V3, N3, 1988. P305-316 Stress measurements were made at two locations along the Bolmen tunnel, Sweden, using both overcoring and hydraulic fracturing techniques. The work was intended to determine far field stress in the region, stress state close to the tunnel, and any anomalies associated with the Staverhult Line. Because of the small stress magnitudes and difficulties associated with the relatively fractured rock mass, considerable experimental uncertainty was attached to the results. It was not possible to determine principal stress directions from the data.
892158 Geotechnical classification of Ivory Coast soils (In French) Cougny. G Proc Ninth Regional Conference for Africa on Soil Mechanics and Foundation Engineering, Lagos, Sept 1987 VI, P81-90. Publ Rotterdam: A A Balkema, 1987
892162 Hydraulic fracturing stress measurements at two sites in Leicestershire, United Kingdom Stewart, I; Monaghan, B G Proc CARE 88 (Conference on Applied Rock Engineering), Newcastle, 6-8 January 1988 P221-233. Publ London: IMM, 1988
Both deposited and residual soils occur in Ivory Coast. Traditional classification systems, developed largely for deposited soils, are inadequate for residual soils, so the LBTP-1986 system has been developed. This classification, based on both genetic and geotechnical identification using traditional laboratory tests, is outlined.
The equipment and techniques used in measuring in situ stress by means of hydraulic fracture are described. The method is illustrated for 2 boreholes, one in sandstone, the other in siliceous tufts. The principal horizontal stress is determined for each. The influence of local geological evidence of stressrelated events on the in situ stress is discussed.
(
1989 Pergamon Press pie. Reproduction not permitted