Evaluación de la resistencia residual. Efecto de la velocidad de corte, temperatura e interacción termo-hidro-mecánica (THM)
(English) The study of residual soil strength and its dependence on intrinsic, external, and coupled effects has gained significant scientific interest due to its relevance in geotechnical field. This doctoral thesis experimentally analyzes the shear behavior of soils under residual conditions, focu...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/694105 |
| Acceso en línea: | http://hdl.handle.net/10803/694105 https://dx.doi.org/10.5821/dissertation-2117-426967 |
| Access Level: | acceso embargado |
| Palabra clave: | Resistencia residual de los suelos Procesos termo-hidro-mecánicos acoplados (THM) Velocidad de corte Temperatura Àrees temàtiques de la UPC::Enginyeria civil 624 - Enginyeria civil i de la construcció en general |
| Sumario: | (English) The study of residual soil strength and its dependence on intrinsic, external, and coupled effects has gained significant scientific interest due to its relevance in geotechnical field. This doctoral thesis experimentally analyzes the shear behavior of soils under residual conditions, focusing on the effects of shear rate, temperature, and coupled thermo-hydro-mechanical (THM) processes. To investigate shear rate and temperature effects, 26 tests with progressive shear rate increments and 70 tests under controlled temperature conditions were conducted on various fine-grained soils. A modified Bromhead ring shear apparatus was used to test shear rates from 0.089 mm/min to 45 mm/min and temperatures from 0 °C to 60 °C under normal stresses of 100, 200, and 300 kPa. The results were analyzed using the rate-, state-, and temperature-dependent friction (RSTF) model. Additionally, scanning electron microscopy (SEM) and interferometric imaging were used to examine shear surfaces. For coupled THM effects, 15 rapid shear tests were performed on Canelles clay, a low-permeability material, using a high-speed ring shear prototype developed at UPC. This device was modified to record temperature and pore pressure during shearing. The results were interpreted using a deformation compatibility model, which successfully reproduced observed deformations and pore pressure changes. The results indicate that heating reduces friction, while cooling increases resistance. At a constant temperature (~20 °C) and normal stress (100–300 kPa), increasing the shear rate generally increased resistance, except in Barcelona silty clay (the least plastic soil), where resistance decreased under 100 kPa normal stress. Other influencing factors include normal stress, clay fraction, plasticity index, specific surface area, activity, and smectite fraction. For rapid shear tests on Canelles clay, thermal dilation effects were significant at shear rates above 0.5 km/h. Pore pressure increased by approximately 2 kPa/°C for temperature rises below 20 °C and 5 kPa/°C for rises above 25 °C. If the soil volume had remained constant, frictional heating would have caused even higher pore pressure increases, reducing effective confining stress and shear strength. In conclusion, residual soil strength is influenced by shear rate, temperature, and THM effects, which are critical for understanding soil behavior in stability assessments. |
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