nowadays acoustic emission (ae) testing based on the kaiser effect (ke) is increasingly used to estimate the in-situ stress in laboratories. in this work, this effect is assessed on cylindrical specimens in numerical simulations of the cyclic loadings including loading, unloading, and re-loading cycles using a 3d code called the particle flow code (pfc) based upon the distinct element method. t...

shear modulus and damping ratio are important input parameters in dynamic analysis. a series of resonant column tests was carried out on pure clays and sand-clay mixtures prepared at different densities to investigate the effects of aggregate content, confining stress, void ratio and clay plasticity on the maximum shear modulus and minimum damping ratio. test results revealed an increase in the...

The fracture mechanics examines the development and expansion of cracks in solids and how they affect the deformation of materials. The stress intensity factors at the tip of the crack and the critical stress intensity factors or fracture toughness of materials are considered in the relevant criteria. There are three main modes of applying forces to a crack including the tensile mode, shear mod...

Nowadays acoustic emission (AE) testing based on the Kaiser Effect (KE) is increasingly used to estimate the in-situ stress in laboratories. In this work, this effect is assessed on cylindrical specimens in numerical simulations of the cyclic loadings including loading, unloading, and re-loading cycles using a 3D code called the particle flow code (PFC) based upon the distinct element method. T...

to investigate the saturation induced collapse deformation behavior of rockfill material, a set of large-scale triaxial tests were conducted in saturated and dry-saturated conditions. specimens were tested under various confining pressures. for dry-saturated tests, specimens were sheared in various stress levels. results of all dry saturated tests indicate a sudden reduction in the specimen vol...

the deformation and stiffness characteristics of a cemented gravely sand was investigated using triaxial equipment. the triaxial tests were conducted in both dry and saturated undrained conditions. artificially cemented samples are prepared using gypsum plaster as the cementing agent. the plaster was mixed with the base soil at the weight percentages of 1.5, 3, 4.5 and 6. the applied confining ...

In order to investigate the mechanical properties of lime mudstone, conventional triaxial compression tests under different confining pressures (0, 5, 15 and 20 MPa) are performed on lime mudstone samples. The test results show that, from the overall perspective of variation law, the axial peak stress, axial peak strain and elastic modulus of lime mudstone tend to gradually increase with increa...

Fracture aperture change under stress has long been considered as one of primary causes of stress sensitivity of fractured gas reservoirs. However, little is known about the evolution of the morphology of fracture apertures on flow property in loading and unloading cycles. This paper reports a stress sensitivity experiment on carbonate core plugs in which Computed Tomography (CT) technology is ...

Representative dynamic properties of municipal solid waste (MSW) are required to perform reliable seismic analyses of MSW landfills. A comprehensive large-scale cyclic triaxial laboratory testing program was performed on MSW retrieved from a landfill in the San Francisco Bay area to evaluate the small-strain shear modulus, and strain-dependent normalized shear modulus reduction and material dam...