Sustainability Issues in Environmental Geotechnics

Thermal properties of the soil gain great importance in engineering projects and situations where heat transfer may take place and affect the soil properties on the whole. Soil gets affected, for example, during laying of bituminous roads, airfield strips, gas or steam pipelines and/or hot water and cold gas lines in unfrozen grounds. In-situ determination of thermal properties of soil is not only time consuming, but in certain cases, costly. The purpose of this study is to understand the variation in thermal properties of virgin soil with addition of different carbonates like potassium carbonate, sodium carbonate and ammonium carbonate using laboratory based Lee’s and Charlton’s apparatus. It is observed that increase in density of soil with any of the three chemicals increases the thermal conductivity, however with the selected chemical the increase is limited to a certain percentage addition after which it does not show any changes as compared to virgin soil.

Egypt has suffered an ill-defined solid waste management (SWM) system for decades which drove the informal sector to take control of many components within the system. As a result, uncontrolled practices prevailed leading to aggravated health, environmental, economic, and social problems. Economic losses due to poor SWM practices are magnified due to the need to deal with the environmental and health consequences. In addition, opportunities to utilize solid waste, particularly municipal and agricultural are often missed. One of the most deleterious consequences to SWM system deficiencies is uncontrolled disposal of municipal solid waste (MSW). This study presents an attempt to calculate the economic cost incurred as a result of leaving open dumps in operation and to evaluate the economic impact of four environmentally viable solutions for decommissioning open dumps. The evaluation of the four options was applied on the existing Shebin El-Kom dumpsite in Egypt. The four options proposed in the report are: Option 1: Complete removal - no waste mining (i.e. no material recovery); Option 2: Complete removal - waste mining (i.e. with material recovery); Option 3: Partial removal – capping; and Option 4: Partial removal – capping – waste mining. The comparative economic evaluation showed that Option 2 will be the most lucrative option that may return with profit and will leave the least negative impact on the public health and environment. However, other options should not be overlooked as political and administrative considerations may opt to one of them. Recommendations and required actions to refine the economic evaluation and to proceed are also presented in the paper. The same assessment methodology can be applied to other open dumping locations grown to similar scales. The key action is to integrate the closure or the decommissioning project with a wise solid waste management practice.

The technical review paper on Geosynthetics, an emerging engineered technology in foundation soil stabilization in the third world nations for sustainable development has tried to elucidate on the need to employ Geosynthetics in solving our challenging soil foundation and environmental geotechnics problems. Geosynthetics are engineered materials artificially produced for soil strength improvement. They appear in various forms applied to Environmental Geotechnics. There have been records of erosion manes and pavement failures in the south-south and southeastern regions of Nigeria and government agencies in these affected regions of the country collect security vote meant to be used to check this natural environmental problems, but lose sight of their responsibility for lack of focus and greed. It is strongly believed that this review paper will be an eye opener to both professionals and those in governance to know that there are cheaper and sustainable solutions to our engineering problems only if we are prepared to embrace what the technological trend of geoengineering has provided the third world nations. Furthermore, this work has elucidated the extent to which weak and expansive soils could be stabilized and possibly check gully erosion disasters destroying the regions by using geosynthetic materials and technology at the nanoscale.

Red mud is one of the major wastes produced from aluminum industry which utilize bauxite (Al₂O₃) as raw material to extract aluminum out of it. This research work investigates the suitable utilization for a particular red mud samples depending upon its permeability and hazardous characteristics. Red mud was stabilized with Fly ash which is another solid waste material produced from thermal power plants and in combination with gypsum. The Fly ash content was varied from 0%, 15% and 25% and gypsum content is varied from 0%, 0.25% and 0.75% of dry weight of the red mud. The main objective of this research work is to evaluate the environmental impact of red mud utilization and explore the means to allay the leaching problem. The effect on the toxic metals in the leachate coming out from the compacted mix when fly ash is added solely or when combined with gypsum to red mud is to be clarified. All the experiments were carried out on each mix to obtain an optimum mix. The permeability and leachate characteristics are studied for different flowing periods from 1 to 7 days of each sample combination. An attempt further was made to understand the metal concentration in the leachate of raw red mud, red mud – fly ash and red mud-flyash–gypsum combinations. It is revealed from the test results and analysis that stabilization with proper proportioning the hazardous metal concentration and permeability of the red mud will decrease with increase in flow period.

Enhanced Oil Recovery (EOR) techniques are becoming the thrust area to recover the residual oil in most of the matured depleted reservoirs. The microscopic displacement efficiency (E_D) of chemical Enhanced Oil Recovery (CEOR) particularly surfactant and/or alkali are dependent on the interfacial properties between the reservoir fluids, mainly crude oil and formation water. This paper discusses the details of all the results of the laboratory experiments carried out to develop an alkali-surfactant (A-S) EOR slug for two depleted oil fields of Barail formation of Upper Assam. A series of experiments such as IFT, adsorption study, compatibility study and thermal stability have been carried out to optimize an A-S formulation. Depending on the anionic nature of most reservoirs of Upper Assam, an anionic surfactant system comprising of a natural surfactant ‘black liquor (BL)’ and a synthetic surfactant ‘Sodium Dodecyl Sulfate (SDS)’ was adopted. This system at its critical micellar concentration (CMC) was mixed with alkalis: Na₂CO₃ and NaHCO₃ and corresponding CMC values at the lowest IFT were recorded. IFT experiments conducted separately with formation water (containing K⁺, Ca²⁺, Mg²⁺) and with laboratory prepared brine (containing Na⁺ only) established that IFT values are lower with formation water than that with the later. This study conducted in the temperature range from 30 °C to 80 °C showed that IFTs increase slightly with temperature, but within the range under study, temperature did not appear to have significant effect on IFT. Based on IFT reducing capabilities, a slug comprising of BL, SDS and Na₂CO₃ was selected for the EOR application in the considered depleted oil fields.

Thermal stability tests were carried out to evaluate the thermal decomposition tendency of the components. Both the surfactant system and alkali did not undergo any thermal degradation upto 90 days. The core flood experiments were carried out on core samples of the selected oil field with the optimized AS formulation following Buckley Leverette theory and calculations were done by Johnson, Bossler and Neumann (JBN) method. AS formulation thus developed in the laboratory was capable of lowering the oil water IFT to the range 10⁻²–10⁻³ mN/m and the components were very much compatible with each other at reservoir temperature. Thermal stability study also produced expected results. The results of the core flood experiments were encouraging as 50–76% additional recovery has been achieved.

Controlled low strength materials (CLSM) is a backfill material which is neither concrete nor soil cement but it has properties similar to both. CLSM is a fluid mixture usually made of Portland cement, water, and fine aggregate or fly ash or both. However, other industrial by-products & recycled materials are also incorporated & encouraged as long as they are considered to be easily available, cost-effective for specific application along with the necessary characteristics of the mixture such as flow ability, strength, and density. Consistency of CLSM is similar to that of a slurry or lean grout, however several hours after placement the material hardens enough to bear loads without settling. Nowadays proper disposal of waste materials which are produced from various industries is a severe problem in many countries causing environmental hazards and raises the potential to contaminate water, air and soil resources and carbon emission. The present experimental research aims to arrive at suitable mix proportion combinations for CLSM by the incorporation of waste industrial by products such as Class C fly ash and GGBS (Ground-granulated blast-furnace slag) as partial replacement for cement. Quarry dust (QD) and Processed Slag Sand (PSS), was utilized in total replacement to natural river sand as fine aggregates, for proportioning of CLSM. Variations were considered in binder ratios and water contents. The fresh and hardened properties of CLSM in terms of flow, unconfined compressive strength were investigated. An attempt has been made to develop predictive flow and strength models known as phenomenological models to assist Engineers in the design of CLSM mixes with these material combinations at a future date or some other place. The findings from this study would benefit Engineers to adopt sustainable practice through incorporation of the above waste or by-products in CLSM – in large quantities unlike concrete or any other material.

Dynamic compaction (DC) is one of the techniques of soil improvement. The impact creates body and surface waves that propagate in the middle of the ground. Soil response to high energy impact during dynamic compaction is very complex. This may be the reason for the slow progress in the development of a rational method for dynamic compaction analysis. However; very few theoretical models are available, which prevents us from understanding all the side effects resulting from it. From US; a case study about the adoption of the dynamic compaction technique with high energy was presented, to facilitate the analysis of the results that cannot be explained by the theory of Lukas, 1986. From the consequences we have found; We proposed a theory (September, 2017 by H. Khelalfa) of soil response to a high energy impact during dynamic compaction. Our theory is based on that there is a reflection of part of the energy received by the compacted soil matrix, implied by the distribution of the energy (E) into two parts, the effective energy (E′) that the sole responsible for soil compaction, and the lost energy (Ep) that the responsible of the neighbouring resulting vibrations. This gives us a wider field for interpreting the results associated with dynamic compaction. It is also observed that the equations obtained through our theory are enter in order to facilitate the calculation of certain parameters. If we take the equations of our theory, we can easily obtain the graphs of the prediction of the level of vibration transmitted by the soil which will influence the environment. The graph of the energy response is divided into four (04) parts (very dangerous, dangerous, limited non-dangerous and non-dangerous vibration); to give us an approach to estimate the efficiency of dynamic compaction and its effects (vibrations).

In the projects of remediation of contaminated site is necessary to produce several technical and cartographic maps that must describe the plan of characterization of the area, the level of the contamination, the sources and the possible techniques for its remediation. Generally, each project uses different ways for the representation of the variables causing an extraordinary effort by technicians of the Institutions that need to use these projects. In this context, one important challenge is the definition of a unifying language in order to communicate the main technical and specific indications in an effective way.

The aim of this work is the proposition of a graphic model useful for the cartographic representation of all documents needed in the field of contaminated sites remediation. According a standardized graphic code was created which signs and symbols that represent the different variables detected in the analysed issue compose. In order to be able to define this model, it was fundamental to reach a great level of synthesis, identifying the relevant information necessary to communicate technical information in a graphical way, trying to produce an effective and clear univocal message.

The proposition was implemented in a case study localized in South Italy. This implementation will be used for the improvement of the developed graphic model and to show its functionality.

In Alkaline Surfactant Enhanced Oil Recovery (ASEOR) an alkali and surfactant/surfactants are used to recover the residual oil that remains after secondary brine flooding. The alkali, which is Sodium Hydroxide (NaOH) in this case, reacts with acidic components in the crude oil to form surface-active substances. A GC-MS spectrum of Upper Assam crude oil reveals the presence of carboxylic acid groups leading to in-situ formation of surfactants, which in turn decreases the interfacial tension (IFT) between the oleic and aqueous phases for better oil recovery. While the anionic surfactants used were Black Liquor (BL) and Sodium Dodecyl Sulphate (SDS). The Critical Micellar concentration (CMC) of 0.6 v/v % BL, 0.4 v/v % of 0.1 M SDS and mixed 0.6 v/v % BL + 0.4 v/v % of 0.1 M SDS one at a time was added NaOH to enhance the effectiveness of NaOH in further decreasing the IFT of the Alkali-Surfactant (AS) slugs. The core flooding experiment were conducted by slugs 0.6 v/v % BL + 0.6% NaOH, 0.4 v/v % of 0.1 M SDS + 0.6% NaOH and mixed slug 0.6 v/v % BL + 0.4 v/v % of 0.1 M SDS +0.6% NaOH. The recovery of residual oil after secondary flood was found to be more in case of mixed slug 0.6 v/v % BL + 0.4 v/v % of 0.1 M SDS +0.6% NaOH about to 32.04% (PV 4.87 cc) out of IOIP (PV 15.2 cc). The paper also make an attempt to study the both dynamic and static adsorptive nature of the AS slugs and found that dynamic adsorption (mg/g) was much less compared to static adsorption (mg/g). And also addition of NaOH to each formulated slug it enhanced the adsorptive nature on PM in terms of economic. The four isotherms: Langmuir, Freundlich, Temkin and Linear were investigated for the best recovery mixed slug 0.6 v/v % BL + 0.4 v/v % of 0.1 M SDS +0.6% NaOH. The Freundlich isotherm found to be best fit adsorption isotherm based on regression co-efficient (R²).

Generally, most of the depleting reservoirs of Upper Assam Basin, India are treated with chemical enhanced oil recovery (CEOR) processes which are one of the tertiary oil recoveries to recover about 30–60% of oil which cannot be produced by means of primary or secondary recovery methods. CEOR processes are mainly emphasise on injecting surfactants (S), alkalis (A) and polymers (P) or a combination S+A or A+P or S+P or A+S+P to the aqueous phase of the depleting reservoirs. The S reduces interfacial tension (IFT) between oil and aqueous phase and increases displacement efficiency (E_D) of the reservoirs. While the A tend to reduce the wettability from oil wet or less water wet to more water wet. A also decrease the adsorption of S into the porous media. Water floods are often very inefficient in naturally sandstone oil reservoirs because many of these reservoirs are mixed-wet or oil-wet towards the end of secondary brine flooding as well as extremely heterogeneous. These reservoirs are challenging targets for chemical flooding because they typically have a high permeability contrast between the fractures and the matrix with low matrix permeability. Some of the world’s largest oil reservoirs are fractured sandstone with high reservoir temperature and high salinity formation brine. Some of them also have low API^o gravity oils, which increases the difficulty of recovering the oil. A slug comprising of surfactant and alkali has been developed that shows promising results for such difficult reservoirs. Ultra-low interfacial tension (IFT) and good aqueous stability were achieved with this surfactant slug in high salinity brine at a high reservoir temperature of 78 ℃. Both static and dynamic imbibition experiments were conducted using a sandstone core of Moran Oil Field. Oil recovery was higher in only SDS+NaOH slug flooding compared to flooding of SDS, NaOH and SDS+NaOH sequentially. The oil recovery is good taking into account that the temperature and salinity conditions were harsh, the core was less permeable and fractured, no mobility control was used, and only a small surfactant slug was injected. The unsteady state coreflood results were interpreted using Johnson-Bossler-Naumann (JBN) method. It showed that both the mechanisms of IFT reduction and wettability alteration were important for oil recovery. Neither IFT reduction nor wettability alteration alone recovered oil as high as the combined contributions from both. So, this study focuses on effect of S, A followed by S+A slug flooding (F1) or flooding of S+A only (F2) to determine the efficiency of residual oil recovery from the depleted Moran Oil Field. The residual oil recovery was calculated by JBN method based on Buckley Leveret assumptions for unsteady state process.

The focus in oil industry is to carry out exploration and exploitation to develop hydrocarbon prospects for the commercial production of oil and natural gas in an environmentally harmonious manner. While producing liquid and gaseous hydrocarbons, large amount of associated water is also produced. In majority of the cases in Upper Assam Basin the oil wells are producing with more than 85% water cut. This produced water has to be treated before discharging it in the environment as it contains harmful constituents in the form of both organics and inorganics. In this study, five samples have been taken for analysis with water content of 94%, 92%, 90%, 84% and 82% which shows the presence of oil and grease, TDS, TSS, DO, Ca, Fe, Na, K, Li, Mg, Mn, Pb and Zn. However the presence of Cr, Cu, Mo, and Ni have not been observed in the samples.

In the present global scenario, much awareness is observed in the environment sector. People are aware of the worst consequences of the environment hazards. Several factors leads to such consequences, industrial waste water being one of them. The direct discharge of the waste water from the industries causes harmful impact on flora and fauna. Therefore, this paper primarily focuses on the treatment processes of the industrial waste water and suggests some novel green approaches to be implemented by the industries for the safe disposal. Hence the samples under study have been treated with microfiltration, ultrafiltration and nanofiltration in the Hollow Fibre Membrane Module set up. The different test samples were collected from Oil fields of Upper Assam Basin. When the samples were treated with microfiltration it was found that some of the parameters like TDS, Turbidity, D.O, Salinity, Oil & Grease and some heavy metals were not within the limits set by the pollution control board of India. Therefore, the samples were further treated with Ultrafiltration. This treatment process resulted in the treatment of most of the pollutants. However turbidity, D.O., Salinity, Oil & Grease were still not within the range. The third treatment process of nanofiltration resulted in the complete eradication of pollutants and all the parameters were found to be within the specified range set by the pollution control board of India. Hence after completion of the three stages of treatment processes consecutively, the treated water may be safely disposed of without any harmful consequences.

The geocell retention system is one of the recent advancement techniques in geotechnical engineering. Geocells impart strength to the backfill soil by confinement, interlocking, and friction. The soil or gravel will be confined in the geocells and this confinement gives additional shear strength by its apparent cohesion. The term “geocell retaining wall” represents the stacking of the various geocell layers to form an earth retention system. The role of reinforcing layers is to restrain the earthquake-induced shear deformation in the soil. Reinforcing geocell layers provide increased stability against dynamic loading besides simply stabilizing the fill. The reinforcing geogrid layers and geocell layers resist rotational and translational failure. This paper contains brief inferences on the application of different geocells with different infill material in retention systems and retaining walls with different backfill materials. A brief overview of the usage of different types of tire waste as backfill material is presented.

This work presents the rupture in a road cut slope with an approximate extension of 100 m, located on the banks of the BR-060 in the urban stretch of the municipality of Guapó/GO. The studies consisted in the execution of a program of field incursions to verify the geotechnical conditions in the indicated section, collection of soil samples, execution of laboratory tests, analysis of slope stabilities and the consequent proposition of stabilization using the structure of containment in gabions of 6.0 m height, 2: 1 slope (H: V) and subsequent planting of grass with protection against surface erosion. The solution adopted in gabions to contain the damaged section proved to be advantageous, considering the economic aspect of other solutions, and its executive simplicity provided speed to the executive process, allowing execution in the rainy season without any kind of intercurrence. In order to verify the current conditions of the implanted system, a visit was made at the beginning of 2017 to the place where the intervention took place and it was found that the implanted works are consistent with the expected operation.

The implementation and operation of a linear enterprise as an energy transmission line involves a series of activities that, depending on the nature of the terrain, can cause diverse impacts to the environment. Among environmental concerns in construction are slope stability, erosion control, sediment generation from excavations and land movements, but also the need to recover areas affected by the work along the route. Thus, in places susceptible to erosive processes, where access openings, areas for the installation of towers and maneuvers, cuts and embankments are necessary, it is necessary to adopt preventive and (or) corrective measures in order to avoid the onset of new erosions and (or) correct existing ones. Another concern is the stability of cutting slopes and embankments that can give rise to landslide susceptible to landslides, both by exposure of unprotected material and by the stability of the soil mass itself. Therefore, in many situations there is a need for practices of containment structures, compaction of landfills, surface protection of soil, execution of surface and/or subsurface drainage systems, among other measures, to minimize possible impacts. These measures also aim to preserve existing facilities, as well as the enterprise itself and the environment. The main justification is the need for recovery and stabilization of accesses, slopes and terraced areas, avoiding possible damages to the soils, vegetation, hydrographic system, sources and the integrity of the enterprise. Therefore, this article presents the procedures adopted to try to return to the areas that have been interfered with, the environmental characteristics that were before and (or) adapt them to the new reality, and also necessary for the operation and maintenance of a transmission line.

With the increasing urbanization and land use, engineers are forced to seek solutions in underground works. In order to enable the implementation of this methodology, it is often used a solo containment system, being it through retaining walls, diaphragm walls, or as usual as it is in Brazil, concrete pile walls. When there is the necessity to achieve greater depths, a common problem occurs while reaching the water level: the outcrop of the water table. Therefore, it is necessary to use, in addition to a containment system, a groundwater lowering system; being it temporary or permanent - or both. The combination of these two systems, containment and groundwater drawdown, then becomes necessary for the execution of underground works in these exceptional cases. The study of the underground water flow behavior and their permanent or temporary drawdown, as well as the influence promoted by concrete pile walls, are topics with low academic production in Brazilian bibliographies. This article aims to deepen the knowledge about the greater efficiency and economy provided by the use of these two systems together by analyzing and producing information in the construction field.