Technological progress is reflected in all industries. Obsolete project manuals in the construction industry are being replaced by digitized automated controls that monitor the project in real-time. One of the main trends is the introduction of technologies based on data analytics. Effective use of technology to collect and analyse data is key to improving a building's planning and management across its life cycle. Building information models, which process digital content related to the entire life cycle of a building, are becoming an effective tool. The main goal of the paper is to design and identify the structure of the developed database, which, based on the acquired knowledge, contains graphical models that have selected non-graphical information.
This paper explores the impact of balconies on the energy demand required for cooling in the arid climate zone of the city of Adrar, in Algeria. For the purpose to assess several situations of the balconies, we have chosen a parametric method based on a campaign of thermal simulations. The open and eliminated balcony type were selected and characterized by four parameters: the balcony to room ratio, the orientation, the window type, and the balcony position. A set of 100 simulations was selected randomly based on the Monte-Carlo probability technique. The final sample was corrected based on Cook’s distance which gave 85 simulations as a final sample size. A generalized regression model was performed to identify the impact of each parameter. The accuracy of the model is above 97% and the sensitivity analysis shows that the most important factor is the balcony to room ratio which could reduce the energy demand up to 26% followed by the window type (24%), the orientation (8%) and the balcony position (5%). This conclusion stresses the idea of considering the balcony as a passive solution to reduce the cooling energy demand.
The treatment and stabilization of soils make it possible to recycle materials on construction sites in preparation for the installation of a final covering or the construction of a road network. In road geotechnics, various materials such as lime, cement, and pozzolans were used as additions to stabilize clay soils. In recent years, bio-polymers and bacteria are of increasing interest to researchers in the field of stabilization and improvement of the physico-mechanical and chemical characteristics of clay soils. Currently, in place of traditional clay treatment techniques and to minimize environmental problems, natural fibrous waste is being used increasingly and spectacularly. Several studies on biotechnological engineering applications already exist, such as the use of vegetation, algae, bacteria, enzymes, and biopolymers. The northern Algerian region where the urban tissue does not stop expanding contains significant potential in terms of wheat straw, which represents a very present agricultural waste. So, there is a local interest in the sustainable development of several regions known to produce wheat. This study is interested in investigating the effect of wheat straw on the stabilization of swelling clay soil. In order to improve the physico-mechanical characteristics of clay soils, a series of laboratory tests (Atterberg limit, Proctor test, direct shear test, Oedometer test, and unconfident compressive strength test) were carried out on reconstituted clay soil with defined initial properties through numerous analyses (e.g., XRD and XRF) and then treated with different vegetable fiber content. The results indicate that there is an improvement in the compressibility characteristics of the treated soil, a remarkable decrease in the swelling index and the compressibility index respectively with increasing percentages of wheat straw.
The negative impact of the production and use of building materials on the environment has become evident, so in recent decades, to find more sustainable, eco-friendly, and low-cost materials, the last research tends to reconsider the use of natural fibers and traditional building materials. This paper aims to develop a bio-composite based on the southern Algerian region's local materials consisting mainly of plaster and waste from date palm trees. Many properties were examined experimentally through previous research of our team (physical, mechanical, and microstructure characteristics) [1, 2] to characterize these materials. Several samples of bio-composite of plaster configurations with short length (20mm) and eight-weight ratios (0.5% - 4%) of palm fibers were prepared for mechanical, thermal, and physical characterizations. In addition, tested all previous properties on the specimens after 28 days of curing in normal conditions. The results show a clear improvement in the bio-composites mechanical performance (an increase in the bending strength with achieving compressive strength) and their thermal properties, which have been well developed (density, thermal conductivity, and specific heat capacity). To enhance the resistance of palm fibers to chemical degradation in the plaster's alkaline environment and improve the adhesion between them, these fibers were treated with a NaOH solution of 1% concentration. The plaster's composites reinforced with date palm fibers can be qualified as eco-friendly and thermal insulation building materials.
The key design strategies that reduce the energy demand of buildings are not present in most thermal codes in many countries. Therefore, modeling techniques offer an alternative to combine the architects' modus operandi with the energy efficiency in the early stages of architectural design and with higher speed and precision. However, a review of the scientific literature using modeling techniques shows that most researchers use a relatively large sample of thermal simulations. This paper proposes a simplified method based on the linear regression modeling technique and considers a relatively smaller sample of thermal simulations. A total of 6 key building design strategies were identified, related to the urban context, building envelope, and shape factor. A simulation protocol containing 60 possible combinations was designed by random selection. In the present study, the Pleiades software was used to estimate the annual energy demand for heating and cooling for a typical dwelling in a humid climate zone. A parametric study and sensitivity analysis to identify the most efficient parameters was performed in SPSS 21. The resulting model predicts the annual energy demand with an accuracy of 93.7%, a root mean square error (RMSE) of 5.88, and a scatter index (SI) of 8.59%. The models performed could efficiently and quickly assist architects while designing the buildings in the architectural practice.
The construction and loading of deep foundations (piles) of high-rise buildings causes a considerable effect in terms of stresses and deformation and requires assessing their impact on the response of adjacent tunnels to deformations, particularly for pile foundations, which are often constructed in locations very close to existing tunnels. The execution process for piles structures generates displacements, stresses, and forces, which are transferred through the piles’ soil surrounding a nearby existing tunnel. The research presented in this paper has led to a significantly improved understanding of pile-tunnel interaction problem. It is crucial for the analysis of the impact of the pile construction on an existing tunnel. The treated topic appears in a setting of an urban environment, where we construct numerous profound foundations, sometimes in contact or adjacent to a. In this paper, the response of the existing tunnel under constructed pile process is studied. Numerical modeling was carried out using Plaxis3D software in which the Mohr-Coulomb Model (MC) has been used for modeling, while the piles/ tunnels are modeled as a linear elastic material. Furthermore, a parametric study is conducted, and its cases are investigated. The displacements and the stresses generated on the tunnel lining decreases with the increase in relative distance between pile and tunnel (spacing), the location/length of the pile from the tunnel, the pile diameter, the number of piles. We have also identified two geometrical parameters of the tunnel: shape section and thickness lining which play a prominent role in the interaction between an existing tunnel and a new pile to excavate.
Publicado en línea: 30 Dec 2021 Páginas: 105 - 114
Resumen
Abstract
The realization of engineering structures in compressible sites, requires in-depth geotechnical reconnaissance, as well as a study of the mechanical behavior of the soil, in order to adapt suitable soil improvement solutions. This is the case with the Annaba viaduct in Algeria, where it was found during the site survey that the soil is poor and very compressible. The foundations in these soils eventually pose the problem of their low bearing capacity and significant settlement. This, therefore, leads to the choice of reinforcement techniques. Among the many methods of improving soils, we have selected the stone column technique. The object of our article is to study the behavior of these columns, in terms of settlement and, through the loading tests on real site, we have found out that the intermediate columns are stiffer and more confined than the bank columns and the percentage reduction in settlements of these two types is important. Then, this experimental study is validated by the Plaxis 2D software, where the configurations are studied to find the best model that approximates the real behavior of the reinforced soil.
Publicado en línea: 30 Dec 2021 Páginas: 115 - 132
Resumen
Abstract
Perlite, a natural glassy volcanic rock could be used as supplementary cementitious material to reduce environmental pollution and the consumption of precious natural resources in the concrete industries. The aim of this work is to assess natural perlite used as 50% aggregates substitution by volume (sand or gravel) and as 10%, 15%, 20% cement substitution in self-compacting concrete. Workability characteristics and mechanical properties were analysed. Results showed that replacing 50% of natural aggregates with 50% of perlite aggregates or substituting cement with 10% of perlite powder generated the best workability characteristics and improved compressive, flexural strength, and elastic modulus of concrete at 28 days. Moreover, the results were combined to develop correlations that prove to be good between mechanical properties of self-compacting. Using perlite as aggregates offers a new source of supply and saves natural aggregates. Also, perlite used as cement substitution helps to reduce PC consumption, cost, and CO2 emission.
Publicado en línea: 30 Dec 2021 Páginas: 133 - 140
Resumen
Abstract
Materials in pavement construction are used due to their material properties. Asphalt mixtures, which are today most used during building pavement construction, have a significant place. Asphalt mixtures are classified as viscoelastic materials due to their material properties. This article focuses on the time delay of the stress behind the strain, which is a specific property for viscoelastic materials. It is particularly focused on one type of asphalt mixture, which is used in the binder course and in the upper base layer. The selected asphalt mixture was tested on a four-bending machine and the samples had a beam shape. The sample was tested at four temperatures and seven frequencies. In the discussion, the article focuses on the comparison of the time delay of the stress Δt behind the strain during the change of temperature and frequency. It is clear from the results that the selected asphalt mixture is significantly affected by the change in temperature as well as the change in frequency. The conclusion is devoted to a summary of the acquired knowledge and observation, which is focused on examples in practice.
Publicado en línea: 30 Dec 2021 Páginas: 141 - 152
Resumen
Abstract
This research was carried out on the state of degradation of the historic core of Annaba city, Algeria. This degradation is caused by multiple factors, the most important of which is the absence of shared responsibility of public actors. The number of collapses multiplied which became a source for the creation of large office buildings with modernist tendencies, but without any architectural identity. The real estate park in downtown Annaba brings together urban entities according to various principles and logics of composition, structuring the urban image of the city of Annaba. The objective of this study is to build a complete catalogue summarizing the structures and fundamental characteristics of old buildings. Initially, this study defines all the notions linked to urban morphology and the typologies of housing. Secondly, an architectural study will be carried out on the “income house”, which represents the basic unit for the development of this historic nucleus. The typological analysis was applied to 44 buildings from the 19th and early 20th centuries located on the boulevard named “Revolution Square” in order to identify a set of common and specific criteria for the classification of “house income”.
Publicado en línea: 30 Dec 2021 Páginas: 153 - 162
Resumen
Abstract
The main goal of Project Info Water is to raise awareness about water management and water resources in the Slovak republic. The target groups of the project are kindergarten students, primary school students, citizens of the affected area, and the government. The project contains four groups of activities – informal, media, online, and presentation activities. Informal activities include thematic brochures with a brief description of the topics Water of Eastern Slovakia, Household water, Flood, Flood protection, Water structures of Eastern Slovakia, Water in the landscape. The presentation activities include the description of webinars, the media, and social activities include print advertisement and access to social media fun pages.
Publicado en línea: 30 Dec 2021 Páginas: 163 - 174
Resumen
Abstract
The mineralogy of fine soils such as clays has always posed problems and remains an uncontrollable phenomenon in the presence of water and causes destructible damage throughout the world. In order to minimize the cost of implementation, it is necessary to find practical and less expensive solutions to ensure the stabilization of these soils by the valorisation of local waste available in nature. This article concerns an experimental study on the treatment of reconstituted soil by the addition of paper ash of different proportions on a set of standardized tests, the preliminary results show that the paper ash to the clay soil improves its swelling potential, its plasticity, its compaction characteristics, and its shear strength parameters.
Publicado en línea: 30 Dec 2021 Páginas: 175 - 187
Resumen
Abstract
In the geotechnical engineering field, shallow foundations are frequently needed to ensure good fieldwork stability. They are also intended to permanently and uniformly transmit all load pressure on the seating floor. However, numerous mechanical constraints, such as bearing capacity of foundations, durability, stability, design of shallow foundations, lead, unfortunately, to a serious realization challenge. Finding an adequate solution presents the main goal and effort of both scholars and professionals. Indeed, the corresponding drawback is observed through the high number of reported damages that occurred in the structure of foundations and the punching failure.
The failure mechanisms of shallow foundations, verified in full size or on scale models, show “sliding surfaces” and rigid (solid) blocks, which can be described with the kinematic method of rigid solids.
The main objective of this study is the application of the kinematic method of rigid solids in the study of the stability of shallow foundations with respect to punching, the purpose of which is to determine the bearing capacity factors Nc, Nγ, and the passive earth pressure coefficient Kp of foundations. In this context, two mechanical models have been proposed with 5 and 7 rigid solids, and a program developed via the MathCAD environment is applied to check the validity of the two previous models. The kinematic method of rigid solids gives results very close and comparable with that of Caquot/Kerisel for the factors of the bearing capacity and passive earth pressure coefficient - the ratio Kp - according to the five- and seven-solid model.
Publicado en línea: 30 Dec 2021 Páginas: 189 - 201
Resumen
Abstract
The work presented in this paper aims to study the durability of mortars, in which part of the sand has been replaced with rubber aggregates from used tires and have undergone a surface treatment with a sodium hydroxide solution (NaOH). The substitution rates studied are 10%, 17.5%, and 25%. The results are compared with ordinary mortar and mortars with untreated rubber aggregates while samples with the same substitution rates were used. To do this, the following properties have been studied: compressive strength, flexural tensile strength, water absorption by capillarity, water absorption by total immersion, water-accessible porosity, water permeability, and resistance to the chemical degradation by sulfuric acid H2SO4.
The results obtained show that the treatment of rubber aggregates by the solution method (NaOH) presented a considerable improvement in mechanical performance (increase in compressive strength and flexural tensile strength) and better durability compared to reference mortar and mortar with untreated rubber granulate.
Publicado en línea: 30 Dec 2021 Páginas: 203 - 217
Resumen
Abstract
The excavation process of tunnels induces stresses and deformation in the surrounding soil. The method of excavation is one of the major problems related to the safety of the operators and the ground stability during the construction of underground works. So, it is necessary to choose an ideal method to minimize the displacements and stresses induced by tunneling.
The main aim of this study is to simulate numerically the effect of different processes of tunneling on ground displacements, the settlements at surface soil and the internal efforts induced in the lining tunnel; in order to select the best process of excavation, which gives us a less effects on displacements generated by tunneling, thus, ensuring the stability and the solidity of the underground constructions. In addition, this study allows us to control and to predict the diverse movements generated by tunneling (displacements, settlements, efforts internes) exclusively for the shallow tunnel nearby to the underground constructions in the urban site. This modeling will be done by employing five different processes for tunnel excavation using the NATM (New Austrian Tunneling Method) method.
The first process, the modeling of the excavation tunnel, is done almost in the same way as in reality; the partial face excavation, with seven slices, made by the excavation. The second process, by partial face excavation, is divided into eleven slices, next, we used the partial face excavation by nine slices, and then in thirteen slices. Finally, the dig is made by full-face excavation.
The paper contributes to the prediction of the response of the soil environment to tunnel excavation using the NATM method and to minimize the diverse movements generated by tunneling. The appropriately chosen methodology confirms that displacements and subsidence are strongly influenced by the tunneling method. The three-dimensional Finite Elements Method using Plaxis3D program has been applied in the numerical simulation. The study resulted in the recommendation of a process that minimizes the effect of excavation on subsidence and ground displacement for a particular Setiha tunnel.
Technological progress is reflected in all industries. Obsolete project manuals in the construction industry are being replaced by digitized automated controls that monitor the project in real-time. One of the main trends is the introduction of technologies based on data analytics. Effective use of technology to collect and analyse data is key to improving a building's planning and management across its life cycle. Building information models, which process digital content related to the entire life cycle of a building, are becoming an effective tool. The main goal of the paper is to design and identify the structure of the developed database, which, based on the acquired knowledge, contains graphical models that have selected non-graphical information.
This paper explores the impact of balconies on the energy demand required for cooling in the arid climate zone of the city of Adrar, in Algeria. For the purpose to assess several situations of the balconies, we have chosen a parametric method based on a campaign of thermal simulations. The open and eliminated balcony type were selected and characterized by four parameters: the balcony to room ratio, the orientation, the window type, and the balcony position. A set of 100 simulations was selected randomly based on the Monte-Carlo probability technique. The final sample was corrected based on Cook’s distance which gave 85 simulations as a final sample size. A generalized regression model was performed to identify the impact of each parameter. The accuracy of the model is above 97% and the sensitivity analysis shows that the most important factor is the balcony to room ratio which could reduce the energy demand up to 26% followed by the window type (24%), the orientation (8%) and the balcony position (5%). This conclusion stresses the idea of considering the balcony as a passive solution to reduce the cooling energy demand.
The treatment and stabilization of soils make it possible to recycle materials on construction sites in preparation for the installation of a final covering or the construction of a road network. In road geotechnics, various materials such as lime, cement, and pozzolans were used as additions to stabilize clay soils. In recent years, bio-polymers and bacteria are of increasing interest to researchers in the field of stabilization and improvement of the physico-mechanical and chemical characteristics of clay soils. Currently, in place of traditional clay treatment techniques and to minimize environmental problems, natural fibrous waste is being used increasingly and spectacularly. Several studies on biotechnological engineering applications already exist, such as the use of vegetation, algae, bacteria, enzymes, and biopolymers. The northern Algerian region where the urban tissue does not stop expanding contains significant potential in terms of wheat straw, which represents a very present agricultural waste. So, there is a local interest in the sustainable development of several regions known to produce wheat. This study is interested in investigating the effect of wheat straw on the stabilization of swelling clay soil. In order to improve the physico-mechanical characteristics of clay soils, a series of laboratory tests (Atterberg limit, Proctor test, direct shear test, Oedometer test, and unconfident compressive strength test) were carried out on reconstituted clay soil with defined initial properties through numerous analyses (e.g., XRD and XRF) and then treated with different vegetable fiber content. The results indicate that there is an improvement in the compressibility characteristics of the treated soil, a remarkable decrease in the swelling index and the compressibility index respectively with increasing percentages of wheat straw.
The negative impact of the production and use of building materials on the environment has become evident, so in recent decades, to find more sustainable, eco-friendly, and low-cost materials, the last research tends to reconsider the use of natural fibers and traditional building materials. This paper aims to develop a bio-composite based on the southern Algerian region's local materials consisting mainly of plaster and waste from date palm trees. Many properties were examined experimentally through previous research of our team (physical, mechanical, and microstructure characteristics) [1, 2] to characterize these materials. Several samples of bio-composite of plaster configurations with short length (20mm) and eight-weight ratios (0.5% - 4%) of palm fibers were prepared for mechanical, thermal, and physical characterizations. In addition, tested all previous properties on the specimens after 28 days of curing in normal conditions. The results show a clear improvement in the bio-composites mechanical performance (an increase in the bending strength with achieving compressive strength) and their thermal properties, which have been well developed (density, thermal conductivity, and specific heat capacity). To enhance the resistance of palm fibers to chemical degradation in the plaster's alkaline environment and improve the adhesion between them, these fibers were treated with a NaOH solution of 1% concentration. The plaster's composites reinforced with date palm fibers can be qualified as eco-friendly and thermal insulation building materials.
The key design strategies that reduce the energy demand of buildings are not present in most thermal codes in many countries. Therefore, modeling techniques offer an alternative to combine the architects' modus operandi with the energy efficiency in the early stages of architectural design and with higher speed and precision. However, a review of the scientific literature using modeling techniques shows that most researchers use a relatively large sample of thermal simulations. This paper proposes a simplified method based on the linear regression modeling technique and considers a relatively smaller sample of thermal simulations. A total of 6 key building design strategies were identified, related to the urban context, building envelope, and shape factor. A simulation protocol containing 60 possible combinations was designed by random selection. In the present study, the Pleiades software was used to estimate the annual energy demand for heating and cooling for a typical dwelling in a humid climate zone. A parametric study and sensitivity analysis to identify the most efficient parameters was performed in SPSS 21. The resulting model predicts the annual energy demand with an accuracy of 93.7%, a root mean square error (RMSE) of 5.88, and a scatter index (SI) of 8.59%. The models performed could efficiently and quickly assist architects while designing the buildings in the architectural practice.
The construction and loading of deep foundations (piles) of high-rise buildings causes a considerable effect in terms of stresses and deformation and requires assessing their impact on the response of adjacent tunnels to deformations, particularly for pile foundations, which are often constructed in locations very close to existing tunnels. The execution process for piles structures generates displacements, stresses, and forces, which are transferred through the piles’ soil surrounding a nearby existing tunnel. The research presented in this paper has led to a significantly improved understanding of pile-tunnel interaction problem. It is crucial for the analysis of the impact of the pile construction on an existing tunnel. The treated topic appears in a setting of an urban environment, where we construct numerous profound foundations, sometimes in contact or adjacent to a. In this paper, the response of the existing tunnel under constructed pile process is studied. Numerical modeling was carried out using Plaxis3D software in which the Mohr-Coulomb Model (MC) has been used for modeling, while the piles/ tunnels are modeled as a linear elastic material. Furthermore, a parametric study is conducted, and its cases are investigated. The displacements and the stresses generated on the tunnel lining decreases with the increase in relative distance between pile and tunnel (spacing), the location/length of the pile from the tunnel, the pile diameter, the number of piles. We have also identified two geometrical parameters of the tunnel: shape section and thickness lining which play a prominent role in the interaction between an existing tunnel and a new pile to excavate.
The realization of engineering structures in compressible sites, requires in-depth geotechnical reconnaissance, as well as a study of the mechanical behavior of the soil, in order to adapt suitable soil improvement solutions. This is the case with the Annaba viaduct in Algeria, where it was found during the site survey that the soil is poor and very compressible. The foundations in these soils eventually pose the problem of their low bearing capacity and significant settlement. This, therefore, leads to the choice of reinforcement techniques. Among the many methods of improving soils, we have selected the stone column technique. The object of our article is to study the behavior of these columns, in terms of settlement and, through the loading tests on real site, we have found out that the intermediate columns are stiffer and more confined than the bank columns and the percentage reduction in settlements of these two types is important. Then, this experimental study is validated by the Plaxis 2D software, where the configurations are studied to find the best model that approximates the real behavior of the reinforced soil.
Perlite, a natural glassy volcanic rock could be used as supplementary cementitious material to reduce environmental pollution and the consumption of precious natural resources in the concrete industries. The aim of this work is to assess natural perlite used as 50% aggregates substitution by volume (sand or gravel) and as 10%, 15%, 20% cement substitution in self-compacting concrete. Workability characteristics and mechanical properties were analysed. Results showed that replacing 50% of natural aggregates with 50% of perlite aggregates or substituting cement with 10% of perlite powder generated the best workability characteristics and improved compressive, flexural strength, and elastic modulus of concrete at 28 days. Moreover, the results were combined to develop correlations that prove to be good between mechanical properties of self-compacting. Using perlite as aggregates offers a new source of supply and saves natural aggregates. Also, perlite used as cement substitution helps to reduce PC consumption, cost, and CO2 emission.
Materials in pavement construction are used due to their material properties. Asphalt mixtures, which are today most used during building pavement construction, have a significant place. Asphalt mixtures are classified as viscoelastic materials due to their material properties. This article focuses on the time delay of the stress behind the strain, which is a specific property for viscoelastic materials. It is particularly focused on one type of asphalt mixture, which is used in the binder course and in the upper base layer. The selected asphalt mixture was tested on a four-bending machine and the samples had a beam shape. The sample was tested at four temperatures and seven frequencies. In the discussion, the article focuses on the comparison of the time delay of the stress Δt behind the strain during the change of temperature and frequency. It is clear from the results that the selected asphalt mixture is significantly affected by the change in temperature as well as the change in frequency. The conclusion is devoted to a summary of the acquired knowledge and observation, which is focused on examples in practice.
This research was carried out on the state of degradation of the historic core of Annaba city, Algeria. This degradation is caused by multiple factors, the most important of which is the absence of shared responsibility of public actors. The number of collapses multiplied which became a source for the creation of large office buildings with modernist tendencies, but without any architectural identity. The real estate park in downtown Annaba brings together urban entities according to various principles and logics of composition, structuring the urban image of the city of Annaba. The objective of this study is to build a complete catalogue summarizing the structures and fundamental characteristics of old buildings. Initially, this study defines all the notions linked to urban morphology and the typologies of housing. Secondly, an architectural study will be carried out on the “income house”, which represents the basic unit for the development of this historic nucleus. The typological analysis was applied to 44 buildings from the 19th and early 20th centuries located on the boulevard named “Revolution Square” in order to identify a set of common and specific criteria for the classification of “house income”.
The main goal of Project Info Water is to raise awareness about water management and water resources in the Slovak republic. The target groups of the project are kindergarten students, primary school students, citizens of the affected area, and the government. The project contains four groups of activities – informal, media, online, and presentation activities. Informal activities include thematic brochures with a brief description of the topics Water of Eastern Slovakia, Household water, Flood, Flood protection, Water structures of Eastern Slovakia, Water in the landscape. The presentation activities include the description of webinars, the media, and social activities include print advertisement and access to social media fun pages.
The mineralogy of fine soils such as clays has always posed problems and remains an uncontrollable phenomenon in the presence of water and causes destructible damage throughout the world. In order to minimize the cost of implementation, it is necessary to find practical and less expensive solutions to ensure the stabilization of these soils by the valorisation of local waste available in nature. This article concerns an experimental study on the treatment of reconstituted soil by the addition of paper ash of different proportions on a set of standardized tests, the preliminary results show that the paper ash to the clay soil improves its swelling potential, its plasticity, its compaction characteristics, and its shear strength parameters.
In the geotechnical engineering field, shallow foundations are frequently needed to ensure good fieldwork stability. They are also intended to permanently and uniformly transmit all load pressure on the seating floor. However, numerous mechanical constraints, such as bearing capacity of foundations, durability, stability, design of shallow foundations, lead, unfortunately, to a serious realization challenge. Finding an adequate solution presents the main goal and effort of both scholars and professionals. Indeed, the corresponding drawback is observed through the high number of reported damages that occurred in the structure of foundations and the punching failure.
The failure mechanisms of shallow foundations, verified in full size or on scale models, show “sliding surfaces” and rigid (solid) blocks, which can be described with the kinematic method of rigid solids.
The main objective of this study is the application of the kinematic method of rigid solids in the study of the stability of shallow foundations with respect to punching, the purpose of which is to determine the bearing capacity factors Nc, Nγ, and the passive earth pressure coefficient Kp of foundations. In this context, two mechanical models have been proposed with 5 and 7 rigid solids, and a program developed via the MathCAD environment is applied to check the validity of the two previous models. The kinematic method of rigid solids gives results very close and comparable with that of Caquot/Kerisel for the factors of the bearing capacity and passive earth pressure coefficient - the ratio Kp - according to the five- and seven-solid model.
The work presented in this paper aims to study the durability of mortars, in which part of the sand has been replaced with rubber aggregates from used tires and have undergone a surface treatment with a sodium hydroxide solution (NaOH). The substitution rates studied are 10%, 17.5%, and 25%. The results are compared with ordinary mortar and mortars with untreated rubber aggregates while samples with the same substitution rates were used. To do this, the following properties have been studied: compressive strength, flexural tensile strength, water absorption by capillarity, water absorption by total immersion, water-accessible porosity, water permeability, and resistance to the chemical degradation by sulfuric acid H2SO4.
The results obtained show that the treatment of rubber aggregates by the solution method (NaOH) presented a considerable improvement in mechanical performance (increase in compressive strength and flexural tensile strength) and better durability compared to reference mortar and mortar with untreated rubber granulate.
The excavation process of tunnels induces stresses and deformation in the surrounding soil. The method of excavation is one of the major problems related to the safety of the operators and the ground stability during the construction of underground works. So, it is necessary to choose an ideal method to minimize the displacements and stresses induced by tunneling.
The main aim of this study is to simulate numerically the effect of different processes of tunneling on ground displacements, the settlements at surface soil and the internal efforts induced in the lining tunnel; in order to select the best process of excavation, which gives us a less effects on displacements generated by tunneling, thus, ensuring the stability and the solidity of the underground constructions. In addition, this study allows us to control and to predict the diverse movements generated by tunneling (displacements, settlements, efforts internes) exclusively for the shallow tunnel nearby to the underground constructions in the urban site. This modeling will be done by employing five different processes for tunnel excavation using the NATM (New Austrian Tunneling Method) method.
The first process, the modeling of the excavation tunnel, is done almost in the same way as in reality; the partial face excavation, with seven slices, made by the excavation. The second process, by partial face excavation, is divided into eleven slices, next, we used the partial face excavation by nine slices, and then in thirteen slices. Finally, the dig is made by full-face excavation.
The paper contributes to the prediction of the response of the soil environment to tunnel excavation using the NATM method and to minimize the diverse movements generated by tunneling. The appropriately chosen methodology confirms that displacements and subsidence are strongly influenced by the tunneling method. The three-dimensional Finite Elements Method using Plaxis3D program has been applied in the numerical simulation. The study resulted in the recommendation of a process that minimizes the effect of excavation on subsidence and ground displacement for a particular Setiha tunnel.