Comportamento drenado e não drenado de sedimentos eólicos artificialmente cimentados

Abstract

Artificial cementation using Portland cement is a long-established soil improvement technique. Also, artificially cemented soils are employed in the study of the bonding effects on geomaterials behavior. Understanding the influence of cementation, especially regarding to the mechanical behavior of cemented soils, ensures safety and efficiency for engineering projects that involves this class of soils. Thus, this study aims to evaluate the mechanical behavior of an aeolian sand molded with different values of void ratios and cement contents, intending to analyze the influence of these variables on compressive, tensile and shear strength of the material. Additionally, there were evaluated the effects of the initial void ratio and cement content on the ultimate state of the soil, reached after major deformations during triaxial tests. Therefore, a Critical State Theory based approach was applied. There were carried out unconfined compression and splitting tensile tests. CID and CIU triaxial tests results from previous studies, carried out with samples from the same material, were analyzed as well. Experimental results from triaxial tests were compared with methods for the assessment of failure envelopes, especially developed for cemented soils. Overall, the results show that the cement content and the initial void ration of the samples are firmly correlated with their behavior, with includes the ultimate state. The increase of the cement content and the decrease of the void ratio rises the strength and the stiffness of the specimens, while reduces their ductility. In most cases, the assessment method proposed by Mitchell (1981), with a friction angle equal to 40°, resulted in a better fit when compared to failure envelopes determined from experimental data. Regarding the ultimate state, it was show that the value of 𝑀 is related to the cement content, while 𝛤 and 𝜆 are controlled by the initial void ratio.