Comportamento mecânico de um solo cimentado

Abstract

For many years the chemical processes mediated by soil biology were ignored in relation to their effects on the geomechanical behavior of soils. However, during the second half of the twentieth century, pioneering studies have recognized the critical role of biochemistry in soil behavior, proving that soil macro-structural behavior depends directly on phenomena and processes that manifest themselves on a micro scale. In the biogeotechnical environment, the precipitation produced by microbial reactions has been the focus of the research that involves the improvement of soil properties. The process known as MICP (microbially induced calcite precipitation) refers to the formation of calcium carbonate due to the presence of microorganisms and their metabolic activities. In this context, the aim is to investigate in a laboratory scale, if the biocementation changes the mechanical behavior of a sandy soil, with respect to its stress-strain response, shear strength and stiffness, for different levels of cementation and confining stresses. After molding and application of the cementation solution, the biocides were submitted to conventional drainage triaxial compression tests, in order to investigate the mechanical behavior. The method used to obtain different levels of cementation, using different solution volumes to perform the biocementation, did not seem satisfactory, since it was not possible to clearly identify the difference in mechanical behavior with the different volumes adopted. In the triaxial tests, it was possible to observe an increase in the initial stiffness of the biocemented specimens in relation to the test specimens without cementation. In addition, a fragile behavior was observed in the rupture of the biocemented samples with a significant drop of post-rupture deviation voltage.