Search results for: embankments

Authors: Bencheikh Messaouda, Aidoud Assia, Salima Boukour, Benamara Fatima Zohra, Boukhatem Ghania, Zegueur Chaouki Salah Eddine

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The utilization of waste materials in civil engineering has gained widespread attention in recent years due to their adverse effects on the environment. One such waste material is coffee grounds, a black residue generated daily across the country after coffee brewing. Instead of disposing of it, there is a growing interest in repurposing it for various agricultural and industrial applications. Utilizing coffee grounds in geotechnical engineering, such as in road embankments, presents an opportunity for its valorization. The study aims to contribute to the valorization of coffee grounds by enhancing the physical and mechanical properties of clayey soils through their incorporation at varying weight percentages (3%, 6%, 9%, 12%) as partial replacements in these soils. This not only addresses the issue of coffee ground waste but also makes a tangible contribution to sustainable development. The findings demonstrate that incorporating coffee grounds generally has positive effects on the physical and mechanical properties of clayey soil. However, the extent of these effects depends on factors such as the quantity of coffee grounds added, the particle size of the grounds, and the characteristics of the soil. Additionally, coffee grounds can improve the compression and tensile strength of clayey soil, resulting in increased stability and reduced susceptibility to deformation under external forces.

Keywords: clay soil, coffee grounds, optimizing, improvement, valorization, waste

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Authors: Eleni Maria Pavlopoulou, Vasiliki N. Georgiannou, Filippos C. Chortis

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The response of M31 sand stabilized with colloidal silica (CS) aqueous gel is investigated in the laboratory. CS is introduced in the water regime, forming a hydrosol. The low viscosity hydrosol thickens in a controllable manner to form a stable, non-toxic gel; the gel fills the pore space, retains the pore water, and supports the grain structure. The role of colloidal silica on subsequent sand behavior is examined with the aid of direct shear, triaxial, and normal compression tests. Under the examined loading modes, while the strength of the treated sand is enhanced, its stiffness may reduce, and its compressibility increase. However, in most geotechnical problems, the loading conditions are complex, involving changes in both stress magnitude and direction. Rotation of principal stresses (σ1, σ2, σ3) in varying amounts expressed as angle α, (from α=0° to 90°) in concurrence with increasing shear stress loading is commonly encountered in soil structures such as foundations, embankments, underwater slopes. To assess the influence of anisotropy on the response of sands before and after their stabilization, hollow cylinder tests were performed. The behavior of stabilized sand is compared with the characteristic sand behavior, i.e., a reduction in peak stress ratio associated with a softer stress-strain response with the increasing angle a. The influence of the magnitude of the intermediate principal stress (σ2) on the mechanical response of treated and untreated sand is also examined.

Keywords: anisotropy, colloidal silica, laboratory tests, sands, soil stabilization

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Authors: Feicheng Liu, Weiming Liao, Jianjing Zhang

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A pile-supported embankment with geosynthetic-reinforced mat (PSGR embankment) has been considered as an effective solution to reduce the total and differential settlement of the embankment constructed over soft soil. In this paper, a new simplified method proposed firstly incorporates the load transfer between piles and surrounding soil and the settlement of pile, and also considers arching effect in embankment fill, membrane effect of geosynthetic reinforcement, and subsoil resistance, to evaluate the behavior of PSGR embankment. Subsoil settlement is assumed to consist of two parts:(1) the settlement of subsoil surface between piles equivalent to that of pile caps assuming the geosynthetic reinforcement without deformation yet; (2) the subsoil subsiding along with the geosynthetic deforming, and the deflected geosynthetic being considered as centenary. The force equilibrium, including loads acting on the upper surface of geosynthetic, subsoil resistance, as well as the stress-strain relationship of the geosynthetic reinforcement at the edge of pile cap, is established, thus the expression of subsoil resistance is deduced, and subsequently the tension of geosynthetic and stress concentration ratio between piles can be calculated. The proposed method is validated through observed data from three field tests and also compared with other eight analytical solutions available in the literature. In addition, a sensitive analysis is provided to demonstrate the influence of with/without considering pile-soil interaction for evaluating the performance of PSGR embankment.

Keywords: pile-supported embankment, geosynthetic, analytical solution, soil arching effect, the settlement of pile, sensitive analysis

Procedia PDF Downloads 133

Authors: Ahmad Idris, O.A. Uche, Ado Y Abdulfatah

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Lateritic soils are found in abundance and are the most common types of soils used in construction of roads and embankments in Nigeria. Strength properties of the soils depend on the amount of compaction applied and the amount of water available in the soil at the time of compaction. In this study, the influence of the compactive effort and that of the amount of water in the soil in the determination of the shear strength properties of lateritic soil was investigated. Lateritic soil sample was collected from an existing borrow pit in Kano, Nigeria and its basic characteristics were determined and the soil was classified according to AASHTO classification method. The soil was then compacted under various compactive efforts and at wide range of moisture contents. The maximum dry density (MDD) and optimum moisture content (OMC) at each compactive effort was determined. Unconfined undrained triaxial test was carried out to determine the shear strength properties of the soil under various conditions of moisture and energy. Preliminary results obtained indicated that the soil is an A-7-5 soil. The final results obtained shows that as the compaction energy is increased, both the cohesion and friction angle increased irrespective of the moisture content used in the compaction. However, when the amount of water in the soil was increased and compaction effort kept constant, only the cohesion of the soil increases while the friction angle shows no any pattern of variation. It was also found that the highest values for cohesion and friction angle were obtained when the soil was compacted at the highest energy and at OMC.

Keywords: laterite, OMC, compaction energy, moisture content

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Authors: Ayad Salih Sabbar, Amin Chegenizadeh, Hamid Nikraz

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Investigation of liquefaction susceptibility of materials that have been used in embankments, slopes, dams, and foundations is very essential. Many catastrophic geo-hazards such as flow slides, declination of foundations, and damage to earth structure are associated with static liquefaction that may occur during abrupt shearing of these materials. Many artificial backfill materials are mixtures of sand with fines and other composition. In order to provide some clarifications and evaluations on the role of fines in static liquefaction behaviour of sand sandy soils, the effect of fines on the liquefaction susceptibility of sand was experimentally examined in the present work over a range of fines content, relative density, and initial confining pressure. The results of an experimental study on various sand-fines mixtures are presented. Undrained static triaxial compression tests were conducted on saturated Perth sand containing 5% bentonite at three different relative densities (10, 50, and 90%), and saturated Perth sand containing both 5% bentonite and slag (2%, 4%, and 6%) at single relative density 10%. Undrained static triaxial tests were performed at three different initial confining pressures (100, 150, and 200 kPa). The brittleness index was used to quantify the liquefaction potential of sand-bentonite-slag mixtures. The results demonstrated that the liquefaction susceptibility of sand-5% bentonite mixture was more than liquefaction susceptibility of clean sandy soil. However, liquefaction potential decreased when both of two fines (bentonite and slag) were used. Liquefaction susceptibility of all mixtures decreased with increasing relative density and initial confining pressure.  

Keywords: liquefaction, bentonite, slag, brittleness index

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Authors: Inci Develioglu, Hasan Firat Pulat

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Sustainable development is one of the most important topics in today's world, and it is also an important research topic for geoenvironmental engineering. Dredging process is performed to expand the river and port channel, flood control and accessing harbors. Every year large amount of sediment are dredged for these purposes. Dredged marine soils can be reused as filling materials, road and foundation embankments, construction materials and wildlife habitat developments. In this study, geotechnical engineering properties and compressibility behavior of dredged soil obtained from the Izmir Bay were investigated. The samples with four different organic matter contents were obtained and particle size distributions, consistency limits, pH and specific gravity tests were performed. The consolidation tests were conducted to examine organic matter content (OMC) effects on compressibility behavior of dredged soil. This study has shown that the OMC has an important effect on the engineering properties of dredged soils. The liquid and plastic limits increased with increasing OMC. The lowest specific gravity belonged to sample which has the maximum OMC. The specific gravity values ranged between 2.76 and 2.52. The maximum void ratio difference belongs to sample with the highest OMC (De_11% = 0.38)_. As the organic matter content of the samples increases, the change in the void ratio has also increased. The compression index increases with increasing OMC.

Keywords: compressibility, consolidation, geotechnical properties, organic matter content, dredged soil

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Authors: Robert G. Nini

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Soil consolidation is one of the biggest problem facing engineers. The consolidation process has an important role in settlement analysis for the embankments and footings resting on clayey soils. The settlement amount is related to the compression and the swelling indexes of the soil. Because the predominant upper soil layer in Lebanon is consisting mainly of clay, this layer is a real challenge for structural and highway engineering. To determine the effect of load and drainage on the engineering consolidation characteristics of Lebanese soil, a full experimental and synthesis study was conducted on different soil samples collected from many locations. This study consists of two parts. During the first part which is an experimental one, the Proctor test and the consolidation test were performed on the collected soil samples. After it, the identifications soil tests as hydrometer, specific gravity and Atterberg limits are done. The consolidation test which is the main test in this research is done by loading the soil for some days then an unloading cycle was applied. It takes two weeks to complete a typical consolidation test. Because of these reasons, during the second part of our research which is based on the analysis of the experiments results, some correlations were found between the main consolidation parameters as compression and swelling indexes with the other soil parameters easy to calculate. The results show that the compression and swelling indexes of Lebanese clays may be roughly estimated using a model involving one or two variables in the form of the natural void ratio and the Atterberg limits. These correlations have increasing importance for site engineers, and the proposed model also seems to be applicable to a wide range of clays worldwide.

Keywords: atterberg limits, clay, compression and swelling indexes, settlement, soil consolidation

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Authors: Mumtaz Ahmed Sohag, Ishaq Ahmed Sohag

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Kebbi State, located in the Nort-West of Nigeria, is rich in water resources as the major rivers viz. Niger and Rima irrigate a vast majority of land. Besides, there is significant amount of groundwater, which farmers use for agriculture purpose. The groundwater is also a major source of agricultural and domestic water as wells are installed in almost all parts of the region. Although Kebbi State is rich in water, however, there are some pertinent issues which are hampering its agricultural productivity. The low lands (locally called Fadama), has spread out to a vast area. It is inundated every year during the rainy season which lasts from June to September every year. The farmers grow rice during the rainy season when water is standing. They cannot do further agricultural activity for almost two months due to high standing water. This has resulted in widespread waterlogging problem. Besides, the impact of climate change is resulting in rapid variation in river/stream flows. The information about water bodies regarding the availability of water for agricultural and other uses and the behavior of rivers at different flows is seldom available. Furthermore, sediment load (suspended and bedload) is not measured due to which land erosion cannot be countered effectively. This study, carried out in seven different irrigation regions of Kebbi state, found that diversion structures need to be constructed at some strategic locations for the supply of surface water to the farmers. The water table needs to be lowered through an effective drainage system. The monitoring of water bodies is crucial for sound data to help efficient regulation and management of water. Construction of embankments is necessary to control frequent floods in the rivers of Niger and Rima. Furthermore, farmers need capacity and awareness for participatory irrigation management.

Keywords: water bodies, floods, agriculture, waterlogging

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Authors: Elena Mugarza, Stephanie Glendinning, Ross Stirling, Colin Davies

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The effects of climate change and increased rainfall events on UK-based infrastructure are observable, with an increasing number being reported on in the national press. The fatal derailment at Stonehaven in 2020 prompted a wider review of Network Rail-owned earthworks assets. The event was indicated by the Rail Accident Investigation Branch (RAIB) to be caused by mis-installed drainage on the adjacent cutting. The slope failure on Snake Pass (public highway A57) was reportedly caused by significant water ingress following numerous storm events and resulted in the road’s closure for several months. This problem is only projected to continue with greater intensity and more prolonged rainfall events forecasted in the future. Subsequently, this project is designed to evaluate effective drainage trench design within infrastructure embankments, considering the capillary barrier phenomenon that may govern their deterioration and resultant failure. Theoretically, the differential between grain sizes of the embankment clays and gravels, customarily used in drainage trenches, would have a limiting effect on infiltration. As such, it is anticipated that the inclusion of an additional material with an intermediate grain size should improve the hydraulic conductivity across the drainage boundary. Multiple drainage designs will be studied using instrumentation within the drain and surrounding clays. Data from the real-world installation at the BIONICS embankment will be collected and compared with laboratory and Finite Element (FE) simulations. This research aims to reduce the risk of infrastructure slope failures by improving the resilience of earthwork drainage and lessening the consequential impact on transportation networks.

Keywords: earthworks, slope drainage, transportation slopes, deterioration, capillary barriers, field study

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Authors: Debora C. Mendes, Matthias Eckert, Claudia S. Moço, Helio Martins, Jean-Pierre Gonçalves, Miguel Oliveira, Jose P. Da Silva

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Disposal of construction and demolition waste (C&DW) in embankments in the periphery of cities causes both environmental and social problems. To achieve the management of C&DW, a detailed analysis of the properties of these materials should be done. In this work we report a comparative study of the physical, chemical and environmental properties of natural and C&DW aggregates from 25 different origins. Assays were performed according to European Standards. Analysis of heavy metals and organic compounds, namely polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), were performed. Finally, properties of concrete prepared with C&DW aggregates are reported. Physical analyses of C&DW aggregates indicated lower quality properties than natural aggregates, particularly for concrete preparation and unbound layers of road pavements. Chemical properties showed that most samples (80%) meet the values required by European regulations for concrete and unbound layers of road pavements. Analyses of heavy metals Cd, Cr, Cu, Pb, Ni, Mo and Zn in the C&DW leachates showed levels below the limits established by the Council Decision of 19 December 2002. Identification and quantification of PCBs and PAHs indicated that few samples shows the presence of these compounds. The measured levels of PCBs and PAHs are also below the limits. Other compounds identified in the C&DW leachates include phthalates and diphenylmethanol. The characterized C&DW aggregates show lower quality properties than natural aggregates but most samples showed to be environmentally safe. A continuous monitoring of the presence of heavy metals and organic compounds should be made to trial safe C&DW aggregates. C&DW aggregates provide a good economic and environmental alternative to natural aggregates.

Keywords: concrete preparation, construction and demolition waste, heavy metals, organic pollutants

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Authors: Ehsan Mehryaar, Seyed Armin Motahari Tabari

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Coarse-grained soils are known and commonly used in a wide range of geotechnical projects, including high earth dams or embankments for their high shear strength. The most important engineering property of these soils is friction angle which represents the interlocking between soil particles and can be applied widely in designing and constructing these earth structures. Friction angle and dilative behavior of coarse-grained soils can be estimated from empirical correlations with in-situ testing and physical properties of the soil or measured directly in the laboratory performing direct shear or triaxial tests. Unfortunately, large-scale testing is difficult, challenging, and expensive and is not possible in most soil mechanic laboratories. So, it is common to remove the large particles and do the tests, which cannot be counted as an exact estimation of the parameters and behavior of the original soil. This paper describes a new methodology to simulate particles grading distribution of a well-graded gravel sample to a smaller scale sample as it can be tested in an ordinary direct shear apparatus to estimate the stress-strain behavior, friction angle, and dilative behavior of the original coarse-grained soil considering its confining pressure, and relative density using a machine learning method. A total number of 72 direct shear tests are performed in 6 different sizes, 3 different confining pressures, and 4 different relative densities. Multivariate Adaptive Regression Spline (MARS) technique was used to develop an equation in order to predict shear strength and dilative behavior based on the size distribution of coarse-grained soil particles. Also, an uncertainty analysis was performed in order to examine the reliability of the proposed equation.

Keywords: MARS, coarse-grained soil, shear strength, uncertainty analysis

Procedia PDF Downloads 135

Authors: Masoud Ghaemi, MohammadJafar Hedayati, Faezeh Yousefzadeh, Hoseinali Heydarzadeh

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According to the statistics of the International Committee on Large Dams, internal erosion and piping (scour) are major causes of the destruction of earth-fill dams. If such dams are constructed in narrow valleys, the valley walls will increase the arching of the dam body due to the transfer of vertical and horizontal stresses, so the occurrence of hydraulic fracturing in these embankments is more likely. Roudbar Dam in Lorestan is a clay-core pebble earth-fill dam constructed in a relatively narrow valley in western Iran. Three years after the onset of impoundment, there has been a fall in dam behavior. Evaluation of the dam behavior based on the data recorded on the instruments installed inside the dam body and foundation confirms the occurrence of internal erosion in the lower and adjacent parts of the core on the left support (abutment). The phenomenon of hydraulic fracturing is one of the main causes of the onset of internal erosion in this dam. Accordingly, the main objective of this paper is to evaluate the validity of this hypothesis. To evaluate the validity of this hypothesis, the dam behavior during construction and impoundment has been first simulated with a three-dimensional numerical model. Then, using validated empirical equations, the safety factor of the occurrence of hydraulic fracturing phenomenon upstream of the dam score was calculated. Then, using the artificial neural network, the failure time of the given section was predicted based on the maximum stress trend created. The study results show that steep slopes of valley walls, sudden changes in coefficient, and differences in compressibility properties of dam body materials have caused considerable stress transfer from core to adjacent valley walls, especially at its lower levels. This has resulted in the coefficient of confidence of the occurrence of hydraulic fracturing in each of these areas being close to one in each of the empirical equations used.

Keywords: arching, artificial neural network, FLAC3D, hydraulic fracturing, internal erosion, pore water pressure

Procedia PDF Downloads 153

Authors: Safitri Nur Wulandari, M. Ivan Adi Perdana, Prathisto L. Panuntun Unggul, R. Dary Wira Mahadika

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In road construction on the soft soil, we need a soil improvement method to improve the soil bearing capacity of the land base so that the soil can withstand the traffic loads. Most of the land in Indonesia has a soft soil, where soft soil is a type of clay that has the consistency of very soft to medium stiff, undrained shear strength, Cu <0:25 kg/cm2, or the estimated value of NSPT <5 blows/ft. This study focuses on the analysis of the effect on preloading load (embarkment) to the amount of settlement ratio on the under of embarkment that will impact on the building cracks around of embarkment. The method used in this research is a superposition method for embarkment distribution on 27 locations with undisturbed soil samples at some borehole point in Java and Kalimantan, Indonesia. Then correlating the results of settlement plate monitoring on the field with Asaoka method. The results of settlement plate monitoring taken from an embarkment of Ahmad Yani airport in Semarang on 32 points. Where the value of Cc (index compressible) soil data based on some laboratory test results, while the value of Cc is not tested obtained from empirical formula Ardhana and Mochtar, 1999. From this research, the results of the field monitoring showed almost the same results with an empirical formulation with the standard deviation of 4% where the formulation of the empirical results of this analysis obtained by linear formula. Value empirical linear formula is to determine the effect of compression heap area as high as 4,25 m is 3,1209x + y = 0.0026 for the slope of the embankment 1: 8 for the same analysis with an initial height of embankment on the field. Provided that at the edge of the embankment settlement worth is not equal to 0 but at a quarter of embankment has a settlement ratio average 0.951 and at the edge of embankment has a settlement ratio 0,049. The influence areas around of embankment are approximately 1 meter for slope 1:8 and 7 meters for slope 1:2. So, it can cause the building cracks, to build in sustainable development.

Keywords: building cracks, influence area, settlement plate, soft soil, empirical formula, embankment

Procedia PDF Downloads 317

Authors: Débora C. Mendes, Matthias Eckert, Cláudia S. Moço, Hélio Martins, Jean-Pierre P. Gonçalves, Miguel Oliveira, José P. Da Silva

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Uncontrolled disposal of construction and demolition waste (C & DW) in embankments in the periphery of cities causes both environmental and social problems, namely erosion, deforestation, water contamination and human conflicts. One of the milestones of EU Horizon 2020 Programme is the management of waste as a resource. To achieve this purpose for C & DW, a detailed analysis of the properties of these materials should be done. In this work we report the physical, chemical and environmental properties of C & DW aggregates from 25 different origins. The results are compared with those of common natural aggregates used in construction. Assays were performed according to European Standards. Additional analysis of heavy metals and organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), were performed to evaluate their environmental impact. Finally, properties of concrete prepared with C & DW aggregates are also reported. Physical analyses of C & DW aggregates indicated lower quality properties than natural aggregates, particularly for concrete preparation and unbound layers of road pavements. Chemical properties showed that most samples (80%) meet the values required by European regulations for concrete and unbound layers of road pavements. Analyses of heavy metals Cd, Cr, Cu, Pb, Ni, Mo and Zn in the C&DW leachates showed levels below the limits established by the Council Decision of 19 December 2002. Identification and quantification of PCBs and PAHs indicated that few samples shows the presence of these compounds. The measured levels of PCBs and PAHs are also below the limits. Other compounds identified in the C&DW leachates include phthalates and diphenylmethanol. In conclusion, the characterized C&DW aggregates show lower quality properties than natural aggregates but most samples showed to be environmentally safe. A continuous monitoring of the presence of heavy metals and organic compounds should be made to trial safe C&DW aggregates. C&DW aggregates provide a good economic and environmental alternative to natural aggregates.

Keywords: concrete preparation, construction and demolition waste, heavy metals, organic pollutants

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Authors: Marwa Ben Khalifa, Zeineb Ben Salem, Wissem Frikha

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The purpose of the present work is to study the consolidation behavior of highly compressible Tunis soft soil “TSS” by means of prefabricated vertical drains (PVD’s) associated to preloading based on laboratory and field investigations. In the first hand, the field performance of PVD’s on the layer of Tunis soft soil was analysed based on the case study of the construction of embankments of “Radès la Goulette” bridge project. PVD’s Geosynthetics drains types were installed with triangular grid pattern until 10 m depth associated with step-by-step surcharge. The monitoring of the soil settlement during preloading stage for Radès La Goulette Bridge project was provided by an instrumentation composed by various type of tassometer installed in the soil. The distribution of water pressure was monitored through piezocone penetration. In the second hand, a laboratory reduced tests are performed on TSS subjected also to preloading and improved with PVD's Mebradrain 88 (Mb88) type. A specific test apparatus was designed and manufactured to study the consolidation. Two series of consolidation tests were performed on TSS specimens. The first series included consolidation tests for soil improved by one central drain. In thesecond series, a triangular mesh of three geodrains was used. The evolution of degree of consolidation and measured settlements versus time derived from laboratory tests and field data were presented and discussed. The obtained results have shown that PVD’s have considerably accelerated the consolidation of Tunis soft soil by shortening the drainage path. The model with mesh of three drains gives results more comparative to field one. A longer consolidation time is observed for the cell improved by a single central drain. A comparison with theoretical analysis, basically that of Barron (1948) and Carillo (1942), was presented. It’s found that these theories overestimate the degree of consolidation in the presence of PVD.

Keywords: tunis soft soil, prefabricated vertical drains, acceleration of consolidation, dissipation of excess pore water pressures, radès bridge project, barron and carillo’s theories

Procedia PDF Downloads 99

Authors: Tanios Saliba, Jad Wakim, Elie Awwad

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Clayey soils exhibit undesirable problems in civil engineering project: poor bearing soil capacity, shrinkage, cracking, …etc. On the other hand, the increasing production of bottom ash and its disposal in an eco-friendly manner is a matter of concern. Soil stabilization using bottom ash is a new technic in the geo-environmental engineering. It can be used wherever a soft clayey soil is encountered in foundations or road subgrade, instead of using old technics such as cement-soil mixing. This new technology can be used for road embankments and clayey foundations platform (shallow or deep foundations) instead of replacing bad soil or using old technics which aren’t eco-friendly. Moreover, applying this new technic in our geotechnical engineering projects can reduce the disposal of the bottom ash problem which is getting bigger day after day. The research consists of mixing clayey soil with different percentages of bottom ash at different values of water content, and evaluates the mechanical properties of every mix: the percentages of bottom ash are 10% 20% 30% 40% and 50% with values of water content of 25% 35% and 45% of the mix’s weight. Before testing the different mixes, clayey soil’s properties were determined: Atterbeg limits, soil’s cohesion and friction angle and particle size distribution. In order to evaluate the mechanical properties and behavior of every mix, different tests are conducted: -Direct shear test in order to determine the cohesion and internal friction angle of every mix. -Unconfined compressive strength (stress strain curve) to determine mix’s elastic modulus and compressive strength. Soil samples are prepared in accordance with the ASTM standards, and tested at different times, in order to be able to emphasize the influence of the curing period on the variation of the mix’s mechanical properties and characteristics. As of today, the results obtained are very promising: the mix’s cohesion and friction angle vary in function of the bottom ash percentage, water content and curing period: the cohesion increases enormously before decreasing for a long curing period (values of mix’s cohesion are larger than intact soil’s cohesion) while internal friction angle keeps on increasing even when the curing period is 28 days (the tests largest curing period), which give us a better soil behavior: less cracks and better soil bearing capacity.

Keywords: bottom ash, Clayey soil, mechanical properties, tests

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Authors: Nayara Torres B. Acioli, José Fernando T. Jucá

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The uncontrolled emission of gases in urban residues' embankment located near urban areas is a social and environmental problem, common in Brazilian cities. Several environmental impacts in the local and global scope may be generated by atmospheric air contamination by the biogas resulted from the decomposition of solid urban materials. In Brazil, the cities of small size figure mostly with 90% of all cities, with the population smaller than 50,000 inhabitants, according to the 2011 IBGE' census, most of the landfill covering layer is composed of clayey, pure soil. The embankments undertaken with pure soil may reach up to 60% of retention of methane, for the other 40% it may be dispersed into the atmosphere. In face of this figures the oxidative covering layer is granted some space of study, envisaging to reduce this perceptual available in the atmosphere, releasing, in spite of methane, carbonic gas which is almost 20 times as less polluting than Methane. This paper exposes the results of studies on the characteristics of the soil used for the oxidative coverage layer of the experimental embankment of Solid Urban Residues (SUR), built in Muribeca-PE, Brazil, supported of the Group of Solid Residues (GSR), located at Federal University of Pernambuco, through laboratory vacuum experiments (determining the characteristics curve), granularity, and permeability, that in soil with saturation over 85% offers dramatic drops in the test of permeability to the air, by little increments of water, based in the existing Brazilian norm for this procedure. The suction was studied, as in the other tests, from the division of prospection of an oxidative coverage layer of 60cm, in the upper half (0.1 m to 0.3 m) and lower half (0.4 m to 0.6 m). Therefore, the consequences to be presented from the lixiviation of the fine materials after 5 years of finalization of the embankment, what made its permeability increase. Concerning its humidity, it is most retained in the upper part, that comprises the compound, with a difference in the order of 8 percent the superior half to inferior half, retaining the least suction from the surface. These results reveal the efficiency of the oxidative coverage layer in retaining the rain water, it has a lower cost when compared to the other types of layer, offering larger availability of this layer as an alternative for a solution for the appropriate disposal of residues.

Keywords: oxidative coverage layer, permeability, suction, saturation

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Authors: Karolina Porada

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Over the last 40 years, there has been a trend in landscape architecture which supporters do not perceive the role of pro-ecological or postmodern solutions in the design of public green spaces as an essential goal, shifting their attention to the 'sculptural' shaping of areas with the use of slopes, hills, embankments, and other forms of terrain. This group of designers can be considered avant-garde, which in its activities refers to land art. Initial research shows that such applications are particularly frequent in places of former post-industrial sites and landfills, utilizing materials such as debris and post-mining waste in their construction. Due to the high degradation of the environment surrounding modern man, the brownfields are a challenge and a field of interest for the representatives of landscape architecture avant-garde, who through their projects try to recover lost lands by means of transformations supported by engineering and ecological knowledge to create places where nature can develop again. The analysis of a dozen or so facilities made it possible to come up with an important conclusion: apart from the cultural aspects (including artistic activities), the green areas formally referring to the land are important in the process of remediation of post-industrial sites and waste recycling (e. g. from construction sites). In these processes, there is also a potential for applying the concept of Natural Based Solutions, i.e. solutions allowing for the natural development of the site in such a way as to use it to cope with environmental problems, such as e.g.  air pollution, soil phytoremediation and climate change. The paper presents examples of modern parks, whose compositions are based on shaping the surface of the terrain in a way referring to the land art, at the same time providing an example of brownfields reuse and application of waste recycling.  For the purposes of object analysis, research methods such as historical-interpretation studies, case studies, qualitative research or the method of logical argumentation were used. The obtained results provide information about the role that landscape architecture can have in the process of remediation of degraded areas, at the same time guaranteeing the benefits, such as the shaping of landscapes attractive in terms of visual appearance, low costs of implementation, and improvement of the natural environment quality.

Keywords: brownfields, contemporary parks, landscape architecture, remediation

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Authors: Ma Yuan, Zhang Mengxi, Akbar Javadi, Chen Longqing

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The structure of sand-filled embankment with cover layer is treated with tipping clay modified with lime on the outside of the packing, and the geotextile is placed between the stuffing and the clay. The packing is usually river sand, and the improved clay protects the sand core against rainwater erosion. The sand-filled embankment with cover layer has practical problems such as high filling embankment, construction restriction, and steep slope. The reinforcement can be applied to the sand-filled embankment with cover layer to solve the complicated problems such as irregular settlement caused by poor stability of the embankment. At present, the research on the sand-filled embankment with cover layer mainly focuses on the sand properties, construction technology, and slope stability, and there are few studies in the experimental field, the deformation characteristics and stability of reinforced sand-filled embankment need further study. In addition, experimental research is relatively rare when the cyclic load is considered in tests. A subgrade structure of geogrid-reinforced sand-filled embankment with cover layer was proposed. The mechanical characteristics, the deformation properties, reinforced behavior and the ultimate bearing capacity of the embankment structure under cyclic loading were studied. For this structure, the geogrids in the sand and the tipping soil are through the geotextile which is arranged in sections continuously so that the geogrids can cross horizontally. Then, the Unsaturated/saturated Soil Triaxial Test System of Geotechnical Consulting and Testing Systems (GCTS), USA was modified to form the loading device of this test, and strain collector was used to measuring deformation and earth pressure of the embankment. A series of cyclic loading model tests were conducted on the geogrid-reinforced sand-filled embankment with a cover layer under a different number of reinforcement layers, the length of reinforcement and thickness of the cover layer. The settlement of the embankment, the normal cumulative deformation of the slope and the earth pressure were studied under different conditions. Besides cyclic loading model tests, model experiments of embankment subjected cyclic-static loading was carried out to analyze ultimate bearing capacity with different loading. The experiment results showed that the vertical cumulative settlement under long-term cyclic loading increases with the decrease of the number of reinforcement layers, length of the reinforcement arrangement and thickness of the tipping soil. Meanwhile, these three factors also have an influence on the decrease of the normal deformation of the embankment slope. The earth pressure around the loading point is significantly affected by putting geogrid in a model embankment. After cyclic loading, the decline of ultimate bearing capacity of the reinforced embankment can be effectively reduced, which is contrary to the unreinforced embankment.

Keywords: cyclic load; geogrid; reinforcement behavior; cumulative deformation; earth pressure

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Authors: Md Kamrul Hassan

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Adaptation interventions are the common response to manage the vulnerabilities of climate change. The nature of adaptation intervention depends on the degree of vulnerability and the capacity of a society. The coping interventions can take the form of hard adaptation – utilising technologies and capital goods like dykes, embankments, seawalls, and/or soft adaptation – engaging knowledge and information sharing, capacity building, policy and strategy development, and innovation. Hard adaptation is quite capital intensive but provides immediate relief from climate change vulnerabilities. This type of adaptation is not real development, as the investment for the adaptation cannot improve the performance – just maintain the status quo of a social or ecological system, and often lead to maladaptation in the long-term. Maladaptation creates a two-way loss for a society – interventions bring further vulnerability on top of the existing vulnerability and investment for getting rid of the consequence of interventions. Hard adaptation is popular to the vulnerable groups, but it focuses so much on the immediate solution and often ignores the environmental issues and future risks of climate change. On the other hand, soft adaptation is education oriented where vulnerable groups learn how to live with climate change impacts. Soft adaptation interventions build the capacity of vulnerable groups through training, innovation, and support, which might enhance the resilience of a system. In consideration of long-term sustainability, soft adaptation can contribute more to resilience than hard adaptation. Taking a developing society as the study context, this study aims to investigate and understand the effectiveness of the adaptation interventions of the coastal community of Sundarbans mangrove forest in Bangladesh. Applying semi-structured interviews with a range of Sundarbans stakeholders including community residents, tourism demand-supply side stakeholders, and conservation and management agencies (e.g., Government, NGOs and international agencies) and document analysis, this paper reports several key insights regarding climate change adaptation. Firstly, while adaptation interventions may offer a short-term to medium-term solution to climate change vulnerabilities, interventions need to be revised for long-term sustainability. Secondly, soft adaptation offers advantages in terms of resilience in a rapidly changing environment, as it is flexible and dynamic. Thirdly, there is a challenge to communicate to educate vulnerable groups to understand more about the future effects of hard adaptation interventions (and the potential for maladaptation). Fourthly, hard adaptation can be used if the interventions do not degrade the environmental balance and if the investment of interventions does not exceed the economic benefit of the interventions. Overall, the goal of an adaptation intervention should be to enhance the resilience of a social or ecological system so that the system can with stand present vulnerabilities and future risks. In order to be sustainable, adaptation interventions should be designed in such way that those can address vulnerabilities and risks of climate change in a long-term timeframe.

Keywords: adaptation, climate change, maladaptation, resilience, Sundarbans, sustainability, vulnerability

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Authors: Sakshi Saxena

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Bangalore is an IT industry-based metropolitan city in the state of Karnataka in India. It has experienced tremendous urbanization at the expense of the environment. The reasons behind development over and near ecologically sensitive areas have been raised by several instances of disappearing lakes. Lakes in Bangalore can be considered commons on both a local and a regional scale and these water bodies are becoming less interconnected because of encroachment in the catchment area. Other sociocultural environmental risks that have led to social issues are now a source of concern. They serve as an example of the transformations in commons, a dilemma that as is transformed from rural to urban areas, as well as the complicated institutional issues associated with governance. According to some scholarly work and ecologists, a nexus of public and commercial institutions is primarily responsible for the depletion of water tanks and the inefficiency of the planning process. It is said that Bangalore's growth as an urban centre, together with the demands it created, particularly on land and water, resulted in the emergence of a middle and upper class that was demanding and self-assured. For the report in focus, it is evident to understand the issues and problems which led to these encroachments and captured violations if any around these lakes and tanks which arose during these decades. To claim watersheds and lake edges as properties, institutional arrangements (organizations, laws, and policies) intersect with planning authorities. Because of unregulated or indiscriminate forms of urbanization, it is claimed that the engagement of actors and negotiations of the process, including government ignorance, are allowing this problem to flourish. In general, the governance of natural resources in India is largely state-based. This is due to the constitutional scheme, which since the Government of India Act, of 1935 has in principle given the power to the states to legislate in this area. Thus, states have the exclusive power to regulate water supplies, irrigation and canals, drainage and embankments, water storage, hydropower, and fisheries. Thus, The main aim is to understand institutional arrangements and the master planning processes behind these arrangements. To understand the ambiguity through an example, it is noted that, Custodianship alone is a role divided between two state and two city-level bodies. This creates regulatory ambiguity and the effects on the environment are such as changes in city temperature, urban flooding, etc. As established, the main kinds of issues around lakes/tanks in Bangalore are encroachment and depletion. This study will further be enhanced by doing a physical survey of three of these lakes focusing on the Bellandur site and the stakeholders involved. According to the study's findings thus far, corrupt politicians and dubious land transaction tools are involved in the real estate industry. It appears that some destruction could have been stopped or at least mitigated in this case if there had been a robust system of urban planning processes involved along with strong institutional arrangements to protect lakes.

Keywords: wetlands, lakes, urbanization, bangalore, politics, reservoirs, municipal jurisdiction, lake connections, institutions

Procedia PDF Downloads 59

Authors: Rajkumar Ghosh

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Rapid urbanization, rising population, changing lifestyles and in-migration, Lucknow is groundwater over-exploited area, with an abstract rate of 1968 m3/day/km2 in Gomti Nagar. The groundwater situation in Gomti Nagar is deteriorating day-by-day. According to the work, the calculated annual water deficiency in Gomti Nagar area will be 28061 Million Litre (ML) in 2022. Within 30 yrs., the water deficiency will be 735570 ML (till 2051). The calculated groundwater recharge in Gomti Nagar was 10813 ML/y (in 2022). The annual groundwater abstraction from Gomti Nagar area was 35332 ML/yr. (in 2022). Bye-laws (≥ 300 sq.m) existing RTRWHs can recharge 17.71 ML/yr. in Gomti Nagar area. The existing RTRWHs are contributing 0.07% for recharging groundwater table. In Gomti Nagar, the water level is dropping at a rate of 1.0 metre per year, and the depth of the water table is less than 30 metre below ground level (mbgl). Natural groundwater recharge is affected by the geomorphological conditions of the surrounding area. Gomti Nagar is located on the erosional terrace (Te) and depositional terrace (d) of the Gomti River. The flood plain in Lucknow city is less active due to the embankments on the both sides of the Gomti River. The alluvium is composed of clay sandy up to a depth of 30m, and the alignment of the Gomti River reveals the presence of sandy soil at shallow depths. Aquifer depth 120 metre. Recharge as in Gomti Nagar (it may vary) 0 – 150 metre. Infiltration rates in alluvial floodplains range from 0.8 to 74 cm/hr. Geologically and Geomorphologically support rapid percolation of rainwater through alluvium in Gomti Nagar, Lucknow city, Uttar Pradesh. Over-exploitation of groundwater causes natural hazards viz. land subsidence, development of cracks on roads and buildings, development of vacuum and compactness of soil/clay which leads towards land subsidence, devastating effects on natural stream flow. Gomti River already transitioning phase from ‘effluent’ to ‘influent’, and saline intrusion in Aquifer –II (among Five aquifers in Lucknow city). A 250 m long crack developed in 2007 due to groundwater depletion in Dullu Khera and Vader Khera village of Kakori, Uttar Pradesh. The groundwater table of Lucknow is declining and water table imbalance occurs due to 17 times less recharge than groundwater exploitation. Uttar Pradesh along with four states have extracted 49% of groundwater in the entire country. In Gomti Nagar area, 27305 no of houses are present and available build up area 3.8 sq. km (60% of plot area) based on Lucknow Development Authority (LDA) Master plan 2031. If RTRWHs would install in all the houses, then 12% harvested rainwater contribute to the water table in Gomti Nagar area. Till 2051, Gomti Nagar area will harvest 91110 ML of rainwater. There are minimalistic chances that any incidence of flood can occur due to RTRWH. Thus, it can conclud that RTRWH is not related to flood happening in urban areas viz. Gomti Nagar.

Keywords: RTRWH, aquifer, groundwater table, rainwater, infiltration

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Authors: C. Bateira, J. Fernandes, A. Costa

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The Douro Demarked Region (DDR) is a production Porto wine region. On the NE of Portugal, the strong incision of the Douro valley developed very steep slopes, organized with agriculture terraces, have experienced an intense and deep transformation in order to implement the mechanization of the work. The old terrace system, based on stone vertical wall support structure, replaced by terraces with earth embankments experienced a huge terrace instability. This terrace instability has important economic and financial consequences on the agriculture enterprises. This paper presents and develops cartographic tools to access the embankment instability and identify the area prone to instability. The priority on this evaluation is related to the use of physically based mathematical models and develop a validation process based on an inventory of the past embankment instability. We used the shallow landslide stability model (SHALSTAB) based on physical parameters such us cohesion (c’), friction angle(ф), hydraulic conductivity, soil depth, soil specific weight (ϱ), slope angle (α) and contributing areas by Multiple Flow Direction Method (MFD). A terraced area can be analysed by this models unless we have very detailed information representative of the terrain morphology. The slope angle and the contributing areas depend on that. We can achieve that propose using digital elevation models (DEM) with great resolution (pixel with 40cm side), resulting from a set of photographs taken by a flight at 100m high with pixel resolution of 12cm. The slope angle results from this DEM. In the other hand, the MFD contributing area models the internal flow and is an important element to define the spatial variation of the soil saturation. That internal flow is based on the DEM. That is supported by the statement that the interflow, although not coincident with the superficial flow, have important similitude with it. Electrical resistivity monitoring values which related with the MFD contributing areas build from a DEM of 1m resolution and revealed a consistent correlation. That analysis, performed on the area, showed a good correlation with R2 of 0,72 and 0,76 at 1,5m and 2m depth, respectively. Considering that, a DEM with 1m resolution was the base to model the real internal flow. Thus, we assumed that the contributing area of 1m resolution modelled by MFD is representative of the internal flow of the area. In order to solve this problem we used a set of generalized DEMs to build the contributing areas used in the SHALSTAB. Those DEMs, with several resolutions (1m and 5m), were built from a set of photographs with 50cm resolution taken by a flight with 5km high. Using this maps combination, we modelled several final maps of terrace instability and performed a validation process with the contingency matrix. The best final instability map resembles the slope map from a DEM of 40cm resolution and a MFD map from a DEM of 1m resolution with a True Positive Rate (TPR) of 0,97, a False Positive Rate of 0,47, Accuracy (ACC) of 0,53, Precision (PVC) of 0,0004 and a TPR/FPR ratio of 2,06.

Keywords: agricultural terraces, cartography, landslides, SHALSTAB, vineyards

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Authors: Chethana V. Casiker, Jagadishakumara B., Sunil G. M., Chaithra K., M. Soubadra Devy

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A majority of the world’s food crops depends on insects for pollination, among which bees are the most dominant taxon. Bees pollinate vegetables, fruits and oilseeds which are rich in essential micronutrients. Besides being a prerequisite for a nutritionally secure diet, agrarian economies such as India depend heavily on pollination for good yield and quality of the product. As cities all over the world expand rapidly, large tracts of green spaces are being built up. This, along with high usage of agricultural chemicals has reduced floral diversity and shrunk bee habitats. Indeed, pollinator decline is being reported from various parts of the world. Further, the FAO has reported a huge increase in the area of land under cultivation of pollinator-dependent crops. In the light of increasing demand for pollination and disappearing natural habitats, it is critical to understand whether and how urban spaces can support pollinators. To this end, this study investigates the influence of landscape and local habitat quality on bee community dynamics. To capture the dynamics of expanding cityscapes, the study employs a space for time substitution, wherein a transect along the gradient of urbanization substitutes a timeframe of increasing urbanization. This will help understand how pollinators would respond to changes induced by increasing intensity of urbanization in the future. Bengaluru, one of the fastest growing cities of Southern India, is an excellent site to study impacts associated with urbanization. With sites moving away from the Bengaluru’s centre and towards its peripheries, this study captures the changes in bee species diversity and richness along a gradient of urbanization. Bees were sampled under different land use types as well as in different types of vegetation, including plantations, croplands, fallow land, parks, lake embankments, and private gardens. The relationship between bee community metrics and key drivers such as a percentage of built-up area, land use practices, and floral resources was examined. Additionally, data collected using questionnaire interviews were used to understand people’s perceptions towards and level of dependence on pollinators. Our results showed that urban areas are capable of supporting bees. In fact, a greater diversity of bees was recorded in urban sites compared to adjoining rural areas. This suggests that bees are able to seek out patchy resources and survive in small fragments of habitat. Bee abundance and species richness correlated positively with floral abundance and richness, indicating the role of vegetation in providing forage and nesting sites which are crucial to their survival. Bee numbers were seen to decrease with increase in built-up area demonstrating that impervious surfaces could act as deterrents. Findings from this study challenge the popular notion of cities being biodiversity-bare spaces. There is indeed scope for conserving bees in urban landscapes, provided that there are city-scale planning and local initiative. Bee conservation can go hand in hand with efforts such as urban gardening and terrace farming that could help cities urbanize sustainably.

Keywords: bee, landscape ecology, urbanization, urban pollination

Procedia PDF Downloads 139