Energy dissipation and dynamic behaviour of clay under cyclic loading

Cao, Yadi; Law, KT

doi:10.1139/t92-011

Cited by 22 publications

(5 citation statements)

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“…For cyclic stress levels higher than 0.55, the cumulative hysteretic work for a given value of peak strain or residual pore-water pressure decreases with increasing cyclic stress level. These observations are contrary to previous findings from fast cyclic tests on clay suggesting a unique relationship between cumulative hysteretic work and residual pore-water pressure (Cao and Law 1992). The meas~~red pore-water pressure that is nonuniform and not representative of the average value within the specimen d~~r i n g fast cyclic loading is the Can.…”

Section: Conditions At Cotnpletioil C$ Each Cyclecontrasting

confidence: 95%

Effective stress response of clay to undrained cyclic loading

Zergoun

Vaid²

1994

Can. Geotech. J.

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The effective stress response of a natural marine clay to slow undrained symmetrical cyclic reversal in shear stress is presented. The effects of cyclic principal stress difference amplitude, cyclic principal effective stress ratio amplitude, initial direction of loading, and step increase in cyclic stress level on the clay stress-strain response are studied under stress conditions of the triaxial test. Characteristic behaviour patterns are identified in terms of effective stresses.

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Section: Conditions At Cotnpletioil C$ Each Cyclecontrasting

confidence: 95%

Effective stress response of clay to undrained cyclic loading

Zergoun

Vaid²

1994

Can. Geotech. J.

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“…Studies on metals by Miner, as reported by Cao and Law [2], show that the effect of damage by one cycle of loading is directly proportional to the energy level of the cycle, independent of where in the time history the particular cycle is applied. Studies by these authors [2] also reported that the damage potential to soils under cyclic loading can be described by the energy dissipated by the soil during the loading.…”

Section: Previous Applicationsmentioning

confidence: 93%

“…Studies by these authors [2] also reported that the damage potential to soils under cyclic loading can be described by the energy dissipated by the soil during the loading. Soil deforms under vibrations during which energy is dissipated through hysteretic damping and plastic deformation of the soil.…”

Section: Previous Applicationsmentioning

confidence: 99%

Energy dissipation and the deformation resistance of bituminous mixtures

1999

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A B S T R A C T R i~ S U M I ~The use of energy dissipation has been extended for assessing the resistance to permanent deformation of bituminous mixtures. The method is found beneficial for accurately determining the end of the linear region from the curves of permanent strain versus number of loading cycles, where the strain rate is constant. An analysis procedure based upon a combined technique of strain rate and energy dissipation method is presented. BACKGROUNDDuring the deformation of a viscoelastic material, part of the total energy required to perform the work is dissipated through viscous losses, with the remainder of the deformational energy being stored elastically. Tschoegl [1] states that "the rate of absorbed energy per unit volume of a viscoelastic material during deformation is equal to the stress power, i.e. the rate at which the work is performed" (see equation (1)):where dW/dt is the rate of absorbed energy per unit volume, o(t) is the applied stress as a function of loading time t, and dg/dt is the strain rate. The total work of deformation, which is the mechanical energy absorbed per unit volume of material in the deformation up to time t, can be formulated as:where W(t) is the total work of deformation and u is the number of load applications as a function of the loading time t. The total energy, W(t), is the combination of both the stored (elastic) energy, We(t ) , and the dissipated energy, Wa(t ). How much of the total energy can be stored and how much can be dissipated depend on the type of deformation and on the properties of the material. W(t) = We(t ) + Wd(t ) Differentiation of the above equation results in:dW _ dWe dWdThe rate at which energy is absorbed by the material during the deformation at time t equals the sum of the rates at which energy is stored and dissipated.In Fig. 1, a load is applied at O and reaches its peak load value at A; the load is maintained until B and then is released to allow the corresponding strain to recover from the deformation. Eventually, if there is no permanent deformation, the strain will return to its original position O (plot I), or otherwise it goes to O'(plot II). In the case of reversible deformation (plot I), the energy stored during the deformation is completely released during the recovery. The dissipated energy is the area within the hysteretic loop (OAB), and the storage (ehstic) energy is the area below the recovery curve (OBC). However, the energy stored in the deformation may not be completely released during the recovery, and hence a permanent (plastic) deformation occurs (plot II). In this case, the dissipated energy is the sum of the areas within the hysteretic energy (O'A'B) and the plastic energy sections (OAA'O'), and the storage (elastic) energy is the 1359-5997/99 9 RILEM 2 1 8

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“…Many researchers around the world have determined the SM and DR by performing undrained CT tests on various soils. Undrained and partially drained CT tests on normally consolidated Champlain clay in Rigaud, Quebec, Canada, and found that the clay would undergo wide settlement and serious damage to bearing capacity, or perhaps fail when loaded under cyclic conditions [8,[16][17][18][19][20][21]. While aggregate content and shear strain have a greater influence on DR, it is less affected by the number of cycles.…”

Section: Introductionmentioning

confidence: 99%

Determination of Dynamic Properties of Fine-Grained Soils at High Cyclic Strains

et al. 2023

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Shear modulus (SM) and damping ratio (DR) are significant in seismic design and the performance of geotechnical systems. The evaluation of soil reactions to dynamic loads, such as earthquakes, blasts, train, and traffic vibrations, necessitates the estimation of dynamic SM and DR. The aim of this research is to determine the cyclic parameters of unsaturated soils in and around Peshawar, and how these properties depend upon the varied confining pressures and shear strains. Undisturbed samples were collected using Shelby tubes from five boreholes at different locations along Jamrud Road, Peshawar. The index properties (grain size distribution, plasticity index, and specific gravity) and dynamic properties of these samples were determined. Three samples of 100 mm in height and 50 mm in diameter were obtained from each Shelby tube. After preparing and mounting the sample in the triaxial cell, the sample is first saturated by increasing the cell and back pressures in increments of 50 kPa until the value of Skempton’s pore pressure parameter (B) reaches ≥ 0.96. Samples were consolidated at confining pressures of 150, 200, and 300 kPa, then subjected to cyclic shear strains of 0.2, 1, 2, 2.5, and 5%. Shear stress–strain hysteresis loops were plotted, and the values of SM and DR were calculated for each cycle. Generally, at shear strains of 0.2 and 1%, the slope of the loops is steep, and gradually becomes gentler at higher strains of 2, 2.5, and 5%. It is found that, with an increasing number of cycles, the SM and DR decrease. The SM decreases with increasing shear strain, whereas the DR increases at shear strains of 0.2–1%, then decreases for strains of 2, 2.5, and 5%. The confining pressure has more influence at a shear strain of 0.2–1%, while little effect has been observed at a shear strain of 2.2–5%. The values of SM are higher at higher confining pressures at a given shear strain. The results show higher stress values during the initial cycles because of the greater effective stress that developed in response to shear strain while, with an increase in the number of cycles, the pore water pressure gradually increases, thereby reducing the effective stress and weakening the bonds between soil particles. In dynamics, when the confining pressure increases, particles are closer to contact, so the travel paths of waves increase. The energy loss will increase, so DR will decrease.

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Energy dissipation and dynamic behaviour of clay under cyclic loading

Cited by 22 publications

References 0 publications

Effective stress response of clay to undrained cyclic loading

Effective stress response of clay to undrained cyclic loading

Energy dissipation and the deformation resistance of bituminous mixtures

Determination of Dynamic Properties of Fine-Grained Soils at High Cyclic Strains

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