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PWP Tester - A simplified cyclic shear test for pore water pressure evolution in granular soils
The build-up of excess pore water pressure (PWP) usually takes place in loose, saturated, coarse-grained soils when subjected to external shear loading (monotonic or cyclic) under prevented water drainage. When the amount of the excess PWP reaches the value of the total stress, the grain structure collapses and the shear strength and stiffness of the soil disappear - the soil behaves as a liquid. Such soil phenomenon is commonly referred to as soil liquefaction. Experimental laboratory testing of the excess PWP build-up in coarse-grained soils is almost restricted to sophisticated undrained cyclic triaxial and simple shear tests. A novel experimental method, the PWP Tester, enabling a simple and fast testing of the excess PWP accumulation in coarse-grained soils has been designed and presented in this thesis. The evolution of the excess PWP during cycling shearing of a cylindrical sand specimen in undrained conditions is measured during the test, and parameters characterising this evolution are determined. Besides an extensive repeatability study, the influence of several soil state variables, e.g. soil density, consolidation pressure, or loading amplitude on the accumulation of the excess PWP was tested. It was shown that the generation of the excess PWP decreased with rising density and consolidation stress, while increasing loading amplitude resulted in faster excess PWP build-up, which confirmed the plausibility of the experimental method. A comparison with the results of undrained cyclic triaxial tests in the case of eight different sands demonstrated a good agreement between both experimental methods, which further corroborated the suitability of the proposed test for a fast investigation of the excess PWP build-up in coarse-grained soils. Specimens prepared according to the proposed procedure in the PWP Tester are pluviated with a funnel under water. The extraction of the sand fabric from the µCT images acquired after the underwater deposition of different sands demonstrated a similar geometrical fabric ...
PWP Tester - A simplified cyclic shear test for pore water pressure evolution in granular soils
The build-up of excess pore water pressure (PWP) usually takes place in loose, saturated, coarse-grained soils when subjected to external shear loading (monotonic or cyclic) under prevented water drainage. When the amount of the excess PWP reaches the value of the total stress, the grain structure collapses and the shear strength and stiffness of the soil disappear - the soil behaves as a liquid. Such soil phenomenon is commonly referred to as soil liquefaction. Experimental laboratory testing of the excess PWP build-up in coarse-grained soils is almost restricted to sophisticated undrained cyclic triaxial and simple shear tests. A novel experimental method, the PWP Tester, enabling a simple and fast testing of the excess PWP accumulation in coarse-grained soils has been designed and presented in this thesis. The evolution of the excess PWP during cycling shearing of a cylindrical sand specimen in undrained conditions is measured during the test, and parameters characterising this evolution are determined. Besides an extensive repeatability study, the influence of several soil state variables, e.g. soil density, consolidation pressure, or loading amplitude on the accumulation of the excess PWP was tested. It was shown that the generation of the excess PWP decreased with rising density and consolidation stress, while increasing loading amplitude resulted in faster excess PWP build-up, which confirmed the plausibility of the experimental method. A comparison with the results of undrained cyclic triaxial tests in the case of eight different sands demonstrated a good agreement between both experimental methods, which further corroborated the suitability of the proposed test for a fast investigation of the excess PWP build-up in coarse-grained soils. Specimens prepared according to the proposed procedure in the PWP Tester are pluviated with a funnel under water. The extraction of the sand fabric from the µCT images acquired after the underwater deposition of different sands demonstrated a similar geometrical fabric ...
PWP Tester - A simplified cyclic shear test for pore water pressure evolution in granular soils
2024-06-10
Theses
Electronic Resource
English
PWP Tester - A simplified cyclic shear test for pore water pressure evolution in granular soils
| TIBKAT | 2024
Density-Dependent Pore Water Pressure Evolution in a Simplified Cyclic Shear Test
| Springer Verlag | 2023
Threshold Shear Strain for Cyclic Pore-Water Pressure in Cohesive Soils
| British Library Online Contents | 2006
Threshold Shear Strain for Cyclic Pore-Water Pressure in Cohesive Soils
| Online Contents | 2006