Abstract

Durante la ejecución de obras de ingeniería es común que el suelo que
se desea utilizar no cumpla con los criterios de calidad que la normativa
correspondiente exige para garantizar la estabilidad estructural de la obra.
Para aquellos casos en los que el valor del índice de plasticidad del suelo
excede el máximo permitido, la estabilización química ha demostrado los
mejores resultados. En esta investigación se realizó un análisis comparativo
del rendimiento del óxido de calcio (CaO) o cal viva, y el cloruro de
sodio (NaCl) o sal de mesa, como agentes estabilizadores. Se agregaron
estos agentes químicos en distintas proporciones al suelo en estudio y se
monitorizaron las variaciones del límite líquido, límite plástico y el índice de
plasticidad. Los resultados demostraron, contrario a lo que tradicionalmente
se espera, que para el caso del suelo en estudio el mejor agente estabilizador
es el cloruro de sodio o sal de mesa, debido a que no solo es más efectivo en
disminuir el índice de plasticidad, sino que además es más barato que la cal.

Abstract

Abstract

Abstract

Abstract

Accurately predicting the installation resistance of offshore piles is important for their design and application. The cone penetration test (CPT) is the most widely used in situ sounding tests for pile drivability analysis and capacity prediction. While there are established empirical correlation methods to connect CPT data with pile installation resistance, the underlying mechanisms behind these correlations have yet to be fully understood. This study performs a numerical analysis to reveal such mechanisms and improve the correlations. The pile installation and cone penetration processes are modelled using a large-deformation finite-element method. For all analyses, a smooth cone and a smooth pile are simulated to quantify the relationship of tip resistance between the pile and CPT. The mechanisms of the two analogous penetration processes are visualized and compared through numerical modelling. As the cone advances, it pushes the soil at the cone tip into the far field. During the pile penetration process, soil heaving can be observed with the soil surface inside the pile moving above the mudline. The soil failure is localized at a small zone around the pile tip. The penetration resistances of pile are correlated to CPT data with the aid of numerical modelling and compared to existing CPT-based design guidelines. A discussion on the pile tip resistance correlated with cone tip resistance is included, and the value of the empirical coefficient for tip resistance kp is obtained.

Abstract

This paper is devoted to the experimental and numerical investigation of the effect of temperature on the volumetric behaviour of silty sandy clay. A temperature-controlled oedometer is developed to study thermally induced volume change. In this system, an electrical ring heater is placed around the conventional oedometer cell, which accommodates the sample. A very low temperature increase rate was achieved by the thermal controller unit to ensure reasonable saturation durations. The interpretation of the test is assisted by the performance of a numerical analysis based on a coupled formulation incorporating the relevant THM phenomena. Heating and cooling at constant isotropic stress show that the thermal volumetric behaviour of clay samples depends on various factors, such as recent stress history prior to the heating and cooling test. The performance and analysis of the thermal consolidation tests have significantly enhanced the understanding of the thermal volumetric behaviour of tested clay and have proved the capability of the numerical formulation to provide adequate modelling capacity.