Fibre addition and Portland cement treatment are used to amend the adverse characteristics of some fine-grained soils and to enhance their mechanical properties. The present study proposes a single power function that quantifies the effects of the amount of cement and porosity on the unconfined compressive (qu) and split tensile (qt) strength of fibre-reinforced fine-grained soil-cement mixtures. The practical value of the equation is that only one unconfined compression (or split tensile) test of a specimen moulded with a specific fibre type, fibre amount, specific cement amount, porosity, and cured for a given time period is required to estimate the strength of the fibre-cement soil mixture. The equation can be used for a wide range of porosities and cement contents, and for other fibre-reinforced fine-grained soils treated with cement.
Performance and safety of geotechnical structures are affected by uncertainties. Yet, the design of dams is nowadays still made using deterministic methods and design codes. Dam optimization in a deterministic setting may lead to compromised safety margins. In this setting, Reliability-Based Design Optimization (RBDO) appears as an alternative, allowing one to optimize dam performance, but respecting specified reliability constraints. In this paper, we employ an efficient and accurate Single-Loop Approach (SLA) in the RBDO of a concrete dam. Considering dam equilibrium reliability constraints, we find the optimal dam base and optimal placement of drainage galleries, for different dam heights and different target reliability index ( β T). We show how the governing failure mode changes for each optimal solution: for large β T, sliding limit state is the active constraint; for smaller β T values, the eccentricity limit state function is found to be the active constraint for the optimum dam. We also investigate how the importance of random parameters change for each optimum solution: for large β T and failure controlled by sliding, the cohesion and friction angle along dam base interface with foundation rock are the most relevant uncertain parameters for dam equilibrium. For smaller β T with failure controlled by eccentricity, the more relevant uncertain geotechnical parameters are the base length of the dam, the specific weight of concrete, and the coefficient of drainage gallery inefficiency.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.