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Undrained strength characteristics of normally consolidated aged clay
85A
843037 Sensitivity of a very hard Plioceue marl Kotzias, P C; Stamatopoulos, A C J Geotech Engng Dir ASCE VI09, NGT12, Dec 1983, P1526-1533
843042 Effect of disturbance due to insertion on vane shear strength of normally consolidated cohesive soils Kimura, T; Saitoh, K Soils Found I,'23, N2, June 1983, P113-124
Marls of a very high initial strength with a relatively low dry density are sandwiched between late Pliocene lignites in the extended lacustrine deposits of Ptolemais, Greece. When they are extracted as waste and carried by conveyor belt to tailings dumps, they liquefy and end up with a slurry-like consistency. The initial high strength is believed to be due to a honeycomb structure strengthened with calcareous bonds between fine calcite grains. During vibration in the transportation phase the grains are dissociated resulting in a non-thixotropic and friable material.
Laboratory vane tests were carried out on a clay and an artificial mixture of clay and sand with plasticity indexes of 50 and 20 respectively. Pore pressure measurements were attempted during insertion and rotation of the vane using two small transducers embedded in samples and one transducer connected to porous tips at the vane blade. It was concluded that: (l) high pore pressure is developed by insertion of the vane, (2) the pore pressure change during the vane rotation is small, (3) the vane shear strength observed is approximately equal to the unconfined compression strength, (4) the ratio of vane shear strength to the vertical consolidation pressure increases with the increase of elapsed time and (5) the ratio ofshear strength to vertical consolidation pressure agreed well with the ratio observed in consolidated and unconsolidated triaxial tests.
843038 Strength tests on coal samples from Gottwaid Colliery (In Polish) Piechota, S Przegl Corn V39, NIO, Oct 1983, P402-407 The results of tests on 1.5cu m samples taken from the solid under natural conditions are presented and compared with results from samples taken from the in situ samples. It is shown that these results agree well with those from similar tests carried out in other countries.
843039 Shear behaviors of sand and clay under three-dimensional stress condition Nakai, T; Matsuoka, H Soils Found I"23, N2, June 1983, P26-42 A stress-strain model under shear is proposed by extending the concept of the Spatial Mobilised Plane (SMP). The validity of the model and the failure criterion based on the SMP are confirmed using the results of triaxial compression, triaxial extension and true triaxial tests on sand and clay. All the soil parameters of this model can be easily determined using conventional triaxial compression tests.
843040 Stability analysis with the simple and the advanced phi----0 method for a failed dike Kishida, T; Hanzawa, H; Nakanowatari, M Soils Found I,'23, N2, June 1983, P69-82 A rock-bund type dyke for land reclamation which had been constructed on highly plastic marine clay failed on completion. Four Dutch cone tests were carried out to determine the failure plane and in situ vane tests and undisturbed sampling in boreholes 100m from the dyke were carried out to obtain the undrained strength of the clay. For determining the undrained strength for the stability analysis, the simple phi = 0 method was represented by use of unconfined compression and in situ vane tests and for the advanced p h i = 0 method, the SHANSEP method and Bjerrum's method were used.
843041 Evaluation of laboratory testing techniques in soil mechanics Saada, A S; Fries, G; Ker, C C Soils Found V23, N2, June 1983, P98-112 Triaxial tests, simple shear tests and hollow cylinder tests were applied to clay and sand soils. Monotonic and cyclic loading were used. It was concluded that the use of the simple shear test to simulate the conditions prevailing during landslides or earthquakes leads to erroneous results when compared to the thin hollow cylinder. For both static and dynamic tests, triaxial tests are better than simple shear tests and the thin hollow cylinder is the most reliable for laboratory soil studies related to strength and stability in both static and earthquake situations.
843O43 Three case studies for short term stability of soft clay deposits Hanzawa, H Soils Found V23, N2, June 1983, P140-154 The results of stability analyses for three structures constructed on normally consolidated clays at or near failure are discussed: (1) the Fao Steel Jetty, Arabian Gulf, (2) the Khor A1-Zubair Embankment, Arabian Gulf and (3) the Daikoku-Cho Dyke, Tokyo Bay, Japan. The undrained strength characteristics of the clays found at the three sites are described and the results of stability analyses obtained using strength values determined by various methods are presented and compared with the field behaviour and actual plane of the structures.
843044 Effect of reconsolidation on undrained strength of normally consolidated cohesive soils Kimura, T; Saitoh, K; Nishihara, S Soils Found V23, N3, Sept 1983, P27-38 The effect of reconsoiidation was studied by conducting K consolidated undrained triaxial tests on specimens subjected to disturbance by extrusion and trimming. Three types of cohesive soil were used, a Kawasaki clay and two artificial mixtures of Kawasaki clay and Toyoura sand. Pore pressures were monitored throughout the tests by an embedded transducer and it was concluded that: (l) soils with lower plasticity indices were more susceptible to disturbance, (2) as reconsolidation pressure increases undrained strength increases and (3) reconsolidation under pressure four times the reconsolidation pressure eliminates the disturbance due to stress release and sample preparation.
843045 Undrained strength characteristics of normally consolidated aged clay Hanzawa, H Soils Found V23, N3, Sept 1983, P39-49 A concept is presented for evaluating the properties of clay subjected to the ageing effect and its undrained strength is discussed in terms of both total and effective stresses. The stress strain behaviour and coefficient of earth pressure at rest are also considered and it is demonstrated that these characteristics of such a clay are different from those of overconsolidated clay formed by release of overburden.
843037 Sensitivity of a very hard Plioceue marl Kotzias, P C; Stamatopoulos, A C J Geotech Engng Dir ASCE VI09, NGT12, Dec 1983, P1526-1533
843042 Effect of disturbance due to insertion on vane shear strength of normally consolidated cohesive soils Kimura, T; Saitoh, K Soils Found I,'23, N2, June 1983, P113-124
Marls of a very high initial strength with a relatively low dry density are sandwiched between late Pliocene lignites in the extended lacustrine deposits of Ptolemais, Greece. When they are extracted as waste and carried by conveyor belt to tailings dumps, they liquefy and end up with a slurry-like consistency. The initial high strength is believed to be due to a honeycomb structure strengthened with calcareous bonds between fine calcite grains. During vibration in the transportation phase the grains are dissociated resulting in a non-thixotropic and friable material.
Laboratory vane tests were carried out on a clay and an artificial mixture of clay and sand with plasticity indexes of 50 and 20 respectively. Pore pressure measurements were attempted during insertion and rotation of the vane using two small transducers embedded in samples and one transducer connected to porous tips at the vane blade. It was concluded that: (l) high pore pressure is developed by insertion of the vane, (2) the pore pressure change during the vane rotation is small, (3) the vane shear strength observed is approximately equal to the unconfined compression strength, (4) the ratio of vane shear strength to the vertical consolidation pressure increases with the increase of elapsed time and (5) the ratio ofshear strength to vertical consolidation pressure agreed well with the ratio observed in consolidated and unconsolidated triaxial tests.
843038 Strength tests on coal samples from Gottwaid Colliery (In Polish) Piechota, S Przegl Corn V39, NIO, Oct 1983, P402-407 The results of tests on 1.5cu m samples taken from the solid under natural conditions are presented and compared with results from samples taken from the in situ samples. It is shown that these results agree well with those from similar tests carried out in other countries.
843039 Shear behaviors of sand and clay under three-dimensional stress condition Nakai, T; Matsuoka, H Soils Found I"23, N2, June 1983, P26-42 A stress-strain model under shear is proposed by extending the concept of the Spatial Mobilised Plane (SMP). The validity of the model and the failure criterion based on the SMP are confirmed using the results of triaxial compression, triaxial extension and true triaxial tests on sand and clay. All the soil parameters of this model can be easily determined using conventional triaxial compression tests.
843040 Stability analysis with the simple and the advanced phi----0 method for a failed dike Kishida, T; Hanzawa, H; Nakanowatari, M Soils Found I,'23, N2, June 1983, P69-82 A rock-bund type dyke for land reclamation which had been constructed on highly plastic marine clay failed on completion. Four Dutch cone tests were carried out to determine the failure plane and in situ vane tests and undisturbed sampling in boreholes 100m from the dyke were carried out to obtain the undrained strength of the clay. For determining the undrained strength for the stability analysis, the simple phi = 0 method was represented by use of unconfined compression and in situ vane tests and for the advanced p h i = 0 method, the SHANSEP method and Bjerrum's method were used.
843041 Evaluation of laboratory testing techniques in soil mechanics Saada, A S; Fries, G; Ker, C C Soils Found V23, N2, June 1983, P98-112 Triaxial tests, simple shear tests and hollow cylinder tests were applied to clay and sand soils. Monotonic and cyclic loading were used. It was concluded that the use of the simple shear test to simulate the conditions prevailing during landslides or earthquakes leads to erroneous results when compared to the thin hollow cylinder. For both static and dynamic tests, triaxial tests are better than simple shear tests and the thin hollow cylinder is the most reliable for laboratory soil studies related to strength and stability in both static and earthquake situations.
843O43 Three case studies for short term stability of soft clay deposits Hanzawa, H Soils Found V23, N2, June 1983, P140-154 The results of stability analyses for three structures constructed on normally consolidated clays at or near failure are discussed: (1) the Fao Steel Jetty, Arabian Gulf, (2) the Khor A1-Zubair Embankment, Arabian Gulf and (3) the Daikoku-Cho Dyke, Tokyo Bay, Japan. The undrained strength characteristics of the clays found at the three sites are described and the results of stability analyses obtained using strength values determined by various methods are presented and compared with the field behaviour and actual plane of the structures.
843044 Effect of reconsolidation on undrained strength of normally consolidated cohesive soils Kimura, T; Saitoh, K; Nishihara, S Soils Found V23, N3, Sept 1983, P27-38 The effect of reconsoiidation was studied by conducting K consolidated undrained triaxial tests on specimens subjected to disturbance by extrusion and trimming. Three types of cohesive soil were used, a Kawasaki clay and two artificial mixtures of Kawasaki clay and Toyoura sand. Pore pressures were monitored throughout the tests by an embedded transducer and it was concluded that: (l) soils with lower plasticity indices were more susceptible to disturbance, (2) as reconsolidation pressure increases undrained strength increases and (3) reconsolidation under pressure four times the reconsolidation pressure eliminates the disturbance due to stress release and sample preparation.
843045 Undrained strength characteristics of normally consolidated aged clay Hanzawa, H Soils Found V23, N3, Sept 1983, P39-49 A concept is presented for evaluating the properties of clay subjected to the ageing effect and its undrained strength is discussed in terms of both total and effective stresses. The stress strain behaviour and coefficient of earth pressure at rest are also considered and it is demonstrated that these characteristics of such a clay are different from those of overconsolidated clay formed by release of overburden.