The continuous monitoring of capillary rise via indirect measures aims to predict and generate al... more The continuous monitoring of capillary rise via indirect measures aims to predict and generate alerts regarding the soil mass deformations, transport leachate from landfills to the soil surface, and carry salts that can damage buildings. Through time-lapse monitoring of the electromagnetic wave's electrical potential and speed, it is possible to correlate via petrophysical relations the measures of electrical potential, electrical resistivity, and dielectric permittivity to the volumetric water content and capillary height. For this, four acrylic columns filled with civil construction material were instrumented. Column 1 - silver electrodes to measure the potential difference with a bench multimeter that measures the spontaneous potential generated by water flow. Column 2 - low-cost soil moisture sensors that measured the electrical potential and converted to bits. Column 3 - resistivimeter that measured the voltage and that was later converted to electrical resistivity and, Col...
Rainfall-induced variations in pore water pressures are the most common sources of significant di... more Rainfall-induced variations in pore water pressures are the most common sources of significant disasters like landslides, dams’ failure, and other structural collapses. This study aimed at communicating preliminary results of seasonal monitoring of the Sobradinho landslide, Brasilia, Brazil, using ambient seismic noise. The noise was recorded before, during and after the rainy season with three L4-3A seismometers (2Hz) installed in a triangular array at the landslide mass. These records were processed using horizontal to vertical spectral ratio (HVSR) technique. As it resulted from the performed analyses, two frequency (ubiquitous (2Hz) and iniquitous (>2Hz)) peaks were observed over HVSR curves. The fluctuations in the secondary peak of HVSR curves are possibly related to the saturated soil properties of landslide mass in response to seasonal meteorological conditions. Experiments with a denser observation system are required to validate such a further behavior. The proposed met...
The conventional mathematical model expressed by the advection–dispersion equation has been widel... more The conventional mathematical model expressed by the advection–dispersion equation has been widely used to describe contaminant transport in porous media. However, studies have shown that it fails to simulate early arrival of contaminant, long tailing breakthrough curves and presents a physical scale-dependency of the dispersion coefficient. Recently, advances in fractional calculus allowed the introduction of fractional order derivatives to model several engineering and physical phenomena, including the anomalous dispersion of solute particles. This approach gives birth to the fractional advection–dispersion equation. This work presents new solutions to the fractional transport equation that satisfies the initial condition of constant solute injection in a semi-infinite medium. The new solution is derived based on a similarity approach. Moreover, laboratory column tests were performed in a Brazilian lateritic soil to validate the new solution with experimental data and compare its ...
Internal erosion is the most important failure mechanism of earth and rockfill dams. Since this t... more Internal erosion is the most important failure mechanism of earth and rockfill dams. Since this type of erosion develops internally and silently, methodologies of data acquisition and processing for dam monitoring are crucial to guarantee a safe operation during the lifespan of these structures. In this context, artificial intelligence techniques show up as tools that can simplify the analysis and verification process not of the internal erosion itself, but of the effects that this pathology causes in the response of the dam to external stimuli. Therefore, within the scope of this paper, a methodological framework for monitoring internal erosion in the body of earth and rockfill dams will be proposed. For that, artificial intelligence methods, especially deep neural autoencoders, will be used to treat the acoustic data collected by geophones installed on a dam. The sensor data is processed to identify patterns and anomalies as well as to classify the dam’s structural health status. ...
The pile foundations’ design is commonly based on the soil’s initial in situ condition during fie... more The pile foundations’ design is commonly based on the soil’s initial in situ condition during field investigations or the assumption of its saturated condition. However, for some regions in tropical weather, a significant part of the pile shaft remains above the groundwater table (i.e., unsaturated condition) during the structure’s lifespan. Only considering a constant moisture condition in the soil (unsaturated or saturated) can overestimate or underestimate the pile design. The soil shear strength governs the shaft resistance of a pile and depends on the soil matric suction, which is significant in the unsaturated zone. In this study, an analytical model is proposed to estimate piles’ unsaturated shaft resistance and encourage the use of unsaturated soil mechanics in engineering practice. The mathematical equation involves well-known parameters from unsaturated soil mechanics theory and simulates the pile shaft resistance variation with its length and time, considering a unidimens...
RESUMO A implementação da Política Nacional de Resíduos Sólidos (Lei nº 12.305, de 2 de agosto de... more RESUMO A implementação da Política Nacional de Resíduos Sólidos (Lei nº 12.305, de 2 de agosto de 2010) foi um marco para a disposição final e o tratamento de resíduos sólidos no país. A contaminação decorrente da negligência na disposição dos resíduos sólidos urbanos atinge sistemas naturais vitais para a existência humana. Torna-se, portanto, fundamental compreender os mecanismos que estão envolvidos no transporte de contaminantes e os dispositivos geotécnicos para mitigar e/ou remediar os impactos. Neste trabalho, é apresentada a utilização de modelagens matemáticas aplicadas aos resultados dos experimentos realizado por Ritter, em 1998, para determinar o transporte dos principais íons inorgânicos, encontrados no lixiviado do aterro Jardim Gramacho (K+, Cl-, Na+ e NH4 +), por difusão química e sorção. O Aterro de Resíduos Urbanos de Jardim Gramacho está localizado em Duque de Caxias, no estado do Rio de Janeiro, e operou por mais de 30 anos, de 1978 a 2012. Para a compreensão dos...
Water flow in porous media is one of many phenomena in nature that can demonstrate both simple an... more Water flow in porous media is one of many phenomena in nature that can demonstrate both simple and complex behaviors. A soil–water retention curve (SWRC) is needed to characterize this flow properly. This curve relates the soil water content and the matric potential (or porepressure), being fundamental for simulating unsaturated soil behaviors. This article proposes a new model based on simple assumptions regarding the saturated and unsaturated branches of soil–water retention curves. Despite its simplicity, the modeling capability of the proposed SWRC is shown for two types of soil. This new SWRC is obtained as a logistic function after solving an ordinary differential equation (ODE). This ODE can also be solved numerically using the Finite Difference Method (FDM), which indicates that the discrete version of the SWRC can be represented as the logistic map for specific parameters. On the other hand, this discrete representation is known to encompass chaotic and fractal behaviors. T...
The occurrence of extreme events of precipitation is commonly responsible for inducing surface ma... more The occurrence of extreme events of precipitation is commonly responsible for inducing surface mass movements in slopes. Landslides are due to the soil-atmosphere interactions. The main inducer of failure in unsaturated slopes is the infiltration, which triggers the reduction of suction, favoring the decrease of stability. Thus, this paper presents the implementation of analytical models to evaluate the probability of transient failure of slopes under unsaturated conditions for a local scale when subjected to antecedent precipitation. In this sense, the model proposed involves an analytical solution to Richards equation for unsaturated flow under transient conditions, capable of analyzing the soil behavior in the infiltration process. Therefore, these analytical models and the geotechnical parameters taken from the case study of a landslide that occurred in Nova Friburgo (Brazil) allowed the simulation of the infiltration process using the precipitation data corresponding to the day...
Finding explicit solutions to the partial differential equations governing the infiltration pheno... more Finding explicit solutions to the partial differential equations governing the infiltration phenomenon tend to be a challenging issue. On account of such complexity, researchers have proposed algebraic equations to model this phenomenon. This paper deals with the solution of the general three-parameter infiltration equation, which is an implicit equation corresponding to the interpolation between the Green-Ampt and Talsma-Parlange infiltration models. By means of the Householders method, the cumulative infiltration is obtained by a rapidly converging iterative procedure. The results are further manipulated in order to obtain the infiltration rate explicitly. The effect of variables involved on the solution is also discussed. A case study is included to demonstrate the use of the proposed algorithm. The formulas proposed provide easy-to-use equations which enable calculations on the fly while considering practical applications.
Environmental degradation and global warming have become a considerable issue in recent years. Th... more Environmental degradation and global warming have become a considerable issue in recent years. The use of more environmentally friendly materials in geotechnical engineering is of preeminent importance. The steel slag aggregate has become an alternative to conventional natural aggregates in road paving works. Therefore, this research aims to evaluate the applicability of the steel slag aggregate as an aggregate for pavement supporting courses (base and subbases). The present research deals with the use of mixtures of steel aggregate and lateritic soil obtained at the site (BR 381/MG) were the subject of the study is located. The experimental program for geotechnical laboratory tests was defined, including the physical and mechanical characterization of the steel slag aggregate, lateritic soil, and three mixtures of these components: 70% steel slag aggregate +30% lateritic soil (M7030), 80% steel slag aggregate +20% lateritic soil (M8020), and 90% steel slag aggregate +10% lateritic soil (M9010). The results of the tests showed that the steel slag aggregate provides satisfactory characteristics to be used as paving material, as long as the expansion of the steel slag aggregate is restrained. The three mixtures of steel slag aggregate and soil, presented satisfactory performance, showing texture compliance, controlled expansion, and high values of California Bearing Ratio (CBR). Therefore, verifying that the steel slag aggregate mixtures can be applied as a base material for road pavements.
One of the main goals of Science is to model nature’s behavior by means of mathematical equations... more One of the main goals of Science is to model nature’s behavior by means of mathematical equations. Such equations tend to ratify some of the basic notions one has about a given phenomena. Conservation of mass, continuity of fluids and equilibrium of phases are some of these “intrinsic” properties which are related to the physical interpretation of a given phenomenon. This way, while considering tailings deposition, the latter must satisfy field equations regarding conservation of the solid phase besides continuity and equilibrium of the liquid phase. In the present paper, a rigorous mathematical approach to the modeling of the main characteristics of tailings is presented. In short, an analytical solution deduced by means of Laplace transform is compared to numerical solutions based on finite differences method, Lax-Wendroff method and the Cubically Interpolated Pseudo-particle (CIP) method. It is shown that CIP method overcomes the problem of spurious numerical dissipation induced by the other numerical methods analyzed. Also, a study of case is done and the numerical solution closely matches the observed experimental data. KeywordsTailings, Hydraullic Deposition, Finite Difference Method, Lax-Wendroff Method, Cubically Interpolated Pseudo-particle.
Implicit equations play a crucial role in Engineering. Based on this importance, several techniqu... more Implicit equations play a crucial role in Engineering. Based on this importance, several techniques have been applied to solve this particular class of equations. When it comes to practical applications, in general, iterative procedures are taken into account. On the other hand, with the improvement of computers, other numerical methods have been developed to provide a more straightforward methodology of solution. Analytical exact approaches seem to have been continuously neglected due to the difficulty inherent in their application; notwithstanding, they are indispensable to validate numerical routines. Lagrange-s Inversion Theorem is a simple mathematical tool which has proved to be widely applicable to engineering problems. In short, it provides the solution to implicit equations by means of an infinite series. To show the validity of this method, the tree-parameter infiltration equation is, for the first time, analytically and exactly solved. After manipulating these series, clo...
The continuous monitoring of capillary rise via indirect measures aims to predict and generate al... more The continuous monitoring of capillary rise via indirect measures aims to predict and generate alerts regarding the soil mass deformations, transport leachate from landfills to the soil surface, and carry salts that can damage buildings. Through time-lapse monitoring of the electromagnetic wave's electrical potential and speed, it is possible to correlate via petrophysical relations the measures of electrical potential, electrical resistivity, and dielectric permittivity to the volumetric water content and capillary height. For this, four acrylic columns filled with civil construction material were instrumented. Column 1 - silver electrodes to measure the potential difference with a bench multimeter that measures the spontaneous potential generated by water flow. Column 2 - low-cost soil moisture sensors that measured the electrical potential and converted to bits. Column 3 - resistivimeter that measured the voltage and that was later converted to electrical resistivity and, Col...
Rainfall-induced variations in pore water pressures are the most common sources of significant di... more Rainfall-induced variations in pore water pressures are the most common sources of significant disasters like landslides, dams’ failure, and other structural collapses. This study aimed at communicating preliminary results of seasonal monitoring of the Sobradinho landslide, Brasilia, Brazil, using ambient seismic noise. The noise was recorded before, during and after the rainy season with three L4-3A seismometers (2Hz) installed in a triangular array at the landslide mass. These records were processed using horizontal to vertical spectral ratio (HVSR) technique. As it resulted from the performed analyses, two frequency (ubiquitous (2Hz) and iniquitous (>2Hz)) peaks were observed over HVSR curves. The fluctuations in the secondary peak of HVSR curves are possibly related to the saturated soil properties of landslide mass in response to seasonal meteorological conditions. Experiments with a denser observation system are required to validate such a further behavior. The proposed met...
The conventional mathematical model expressed by the advection–dispersion equation has been widel... more The conventional mathematical model expressed by the advection–dispersion equation has been widely used to describe contaminant transport in porous media. However, studies have shown that it fails to simulate early arrival of contaminant, long tailing breakthrough curves and presents a physical scale-dependency of the dispersion coefficient. Recently, advances in fractional calculus allowed the introduction of fractional order derivatives to model several engineering and physical phenomena, including the anomalous dispersion of solute particles. This approach gives birth to the fractional advection–dispersion equation. This work presents new solutions to the fractional transport equation that satisfies the initial condition of constant solute injection in a semi-infinite medium. The new solution is derived based on a similarity approach. Moreover, laboratory column tests were performed in a Brazilian lateritic soil to validate the new solution with experimental data and compare its ...
Internal erosion is the most important failure mechanism of earth and rockfill dams. Since this t... more Internal erosion is the most important failure mechanism of earth and rockfill dams. Since this type of erosion develops internally and silently, methodologies of data acquisition and processing for dam monitoring are crucial to guarantee a safe operation during the lifespan of these structures. In this context, artificial intelligence techniques show up as tools that can simplify the analysis and verification process not of the internal erosion itself, but of the effects that this pathology causes in the response of the dam to external stimuli. Therefore, within the scope of this paper, a methodological framework for monitoring internal erosion in the body of earth and rockfill dams will be proposed. For that, artificial intelligence methods, especially deep neural autoencoders, will be used to treat the acoustic data collected by geophones installed on a dam. The sensor data is processed to identify patterns and anomalies as well as to classify the dam’s structural health status. ...
The pile foundations’ design is commonly based on the soil’s initial in situ condition during fie... more The pile foundations’ design is commonly based on the soil’s initial in situ condition during field investigations or the assumption of its saturated condition. However, for some regions in tropical weather, a significant part of the pile shaft remains above the groundwater table (i.e., unsaturated condition) during the structure’s lifespan. Only considering a constant moisture condition in the soil (unsaturated or saturated) can overestimate or underestimate the pile design. The soil shear strength governs the shaft resistance of a pile and depends on the soil matric suction, which is significant in the unsaturated zone. In this study, an analytical model is proposed to estimate piles’ unsaturated shaft resistance and encourage the use of unsaturated soil mechanics in engineering practice. The mathematical equation involves well-known parameters from unsaturated soil mechanics theory and simulates the pile shaft resistance variation with its length and time, considering a unidimens...
RESUMO A implementação da Política Nacional de Resíduos Sólidos (Lei nº 12.305, de 2 de agosto de... more RESUMO A implementação da Política Nacional de Resíduos Sólidos (Lei nº 12.305, de 2 de agosto de 2010) foi um marco para a disposição final e o tratamento de resíduos sólidos no país. A contaminação decorrente da negligência na disposição dos resíduos sólidos urbanos atinge sistemas naturais vitais para a existência humana. Torna-se, portanto, fundamental compreender os mecanismos que estão envolvidos no transporte de contaminantes e os dispositivos geotécnicos para mitigar e/ou remediar os impactos. Neste trabalho, é apresentada a utilização de modelagens matemáticas aplicadas aos resultados dos experimentos realizado por Ritter, em 1998, para determinar o transporte dos principais íons inorgânicos, encontrados no lixiviado do aterro Jardim Gramacho (K+, Cl-, Na+ e NH4 +), por difusão química e sorção. O Aterro de Resíduos Urbanos de Jardim Gramacho está localizado em Duque de Caxias, no estado do Rio de Janeiro, e operou por mais de 30 anos, de 1978 a 2012. Para a compreensão dos...
Water flow in porous media is one of many phenomena in nature that can demonstrate both simple an... more Water flow in porous media is one of many phenomena in nature that can demonstrate both simple and complex behaviors. A soil–water retention curve (SWRC) is needed to characterize this flow properly. This curve relates the soil water content and the matric potential (or porepressure), being fundamental for simulating unsaturated soil behaviors. This article proposes a new model based on simple assumptions regarding the saturated and unsaturated branches of soil–water retention curves. Despite its simplicity, the modeling capability of the proposed SWRC is shown for two types of soil. This new SWRC is obtained as a logistic function after solving an ordinary differential equation (ODE). This ODE can also be solved numerically using the Finite Difference Method (FDM), which indicates that the discrete version of the SWRC can be represented as the logistic map for specific parameters. On the other hand, this discrete representation is known to encompass chaotic and fractal behaviors. T...
The occurrence of extreme events of precipitation is commonly responsible for inducing surface ma... more The occurrence of extreme events of precipitation is commonly responsible for inducing surface mass movements in slopes. Landslides are due to the soil-atmosphere interactions. The main inducer of failure in unsaturated slopes is the infiltration, which triggers the reduction of suction, favoring the decrease of stability. Thus, this paper presents the implementation of analytical models to evaluate the probability of transient failure of slopes under unsaturated conditions for a local scale when subjected to antecedent precipitation. In this sense, the model proposed involves an analytical solution to Richards equation for unsaturated flow under transient conditions, capable of analyzing the soil behavior in the infiltration process. Therefore, these analytical models and the geotechnical parameters taken from the case study of a landslide that occurred in Nova Friburgo (Brazil) allowed the simulation of the infiltration process using the precipitation data corresponding to the day...
Finding explicit solutions to the partial differential equations governing the infiltration pheno... more Finding explicit solutions to the partial differential equations governing the infiltration phenomenon tend to be a challenging issue. On account of such complexity, researchers have proposed algebraic equations to model this phenomenon. This paper deals with the solution of the general three-parameter infiltration equation, which is an implicit equation corresponding to the interpolation between the Green-Ampt and Talsma-Parlange infiltration models. By means of the Householders method, the cumulative infiltration is obtained by a rapidly converging iterative procedure. The results are further manipulated in order to obtain the infiltration rate explicitly. The effect of variables involved on the solution is also discussed. A case study is included to demonstrate the use of the proposed algorithm. The formulas proposed provide easy-to-use equations which enable calculations on the fly while considering practical applications.
Environmental degradation and global warming have become a considerable issue in recent years. Th... more Environmental degradation and global warming have become a considerable issue in recent years. The use of more environmentally friendly materials in geotechnical engineering is of preeminent importance. The steel slag aggregate has become an alternative to conventional natural aggregates in road paving works. Therefore, this research aims to evaluate the applicability of the steel slag aggregate as an aggregate for pavement supporting courses (base and subbases). The present research deals with the use of mixtures of steel aggregate and lateritic soil obtained at the site (BR 381/MG) were the subject of the study is located. The experimental program for geotechnical laboratory tests was defined, including the physical and mechanical characterization of the steel slag aggregate, lateritic soil, and three mixtures of these components: 70% steel slag aggregate +30% lateritic soil (M7030), 80% steel slag aggregate +20% lateritic soil (M8020), and 90% steel slag aggregate +10% lateritic soil (M9010). The results of the tests showed that the steel slag aggregate provides satisfactory characteristics to be used as paving material, as long as the expansion of the steel slag aggregate is restrained. The three mixtures of steel slag aggregate and soil, presented satisfactory performance, showing texture compliance, controlled expansion, and high values of California Bearing Ratio (CBR). Therefore, verifying that the steel slag aggregate mixtures can be applied as a base material for road pavements.
One of the main goals of Science is to model nature’s behavior by means of mathematical equations... more One of the main goals of Science is to model nature’s behavior by means of mathematical equations. Such equations tend to ratify some of the basic notions one has about a given phenomena. Conservation of mass, continuity of fluids and equilibrium of phases are some of these “intrinsic” properties which are related to the physical interpretation of a given phenomenon. This way, while considering tailings deposition, the latter must satisfy field equations regarding conservation of the solid phase besides continuity and equilibrium of the liquid phase. In the present paper, a rigorous mathematical approach to the modeling of the main characteristics of tailings is presented. In short, an analytical solution deduced by means of Laplace transform is compared to numerical solutions based on finite differences method, Lax-Wendroff method and the Cubically Interpolated Pseudo-particle (CIP) method. It is shown that CIP method overcomes the problem of spurious numerical dissipation induced by the other numerical methods analyzed. Also, a study of case is done and the numerical solution closely matches the observed experimental data. KeywordsTailings, Hydraullic Deposition, Finite Difference Method, Lax-Wendroff Method, Cubically Interpolated Pseudo-particle.
Implicit equations play a crucial role in Engineering. Based on this importance, several techniqu... more Implicit equations play a crucial role in Engineering. Based on this importance, several techniques have been applied to solve this particular class of equations. When it comes to practical applications, in general, iterative procedures are taken into account. On the other hand, with the improvement of computers, other numerical methods have been developed to provide a more straightforward methodology of solution. Analytical exact approaches seem to have been continuously neglected due to the difficulty inherent in their application; notwithstanding, they are indispensable to validate numerical routines. Lagrange-s Inversion Theorem is a simple mathematical tool which has proved to be widely applicable to engineering problems. In short, it provides the solution to implicit equations by means of an infinite series. To show the validity of this method, the tree-parameter infiltration equation is, for the first time, analytically and exactly solved. After manipulating these series, clo...
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