Soil Treatment & Soil Reinforcement Techniques

Many construction buildings and Structural barrier members that was built before 90s in USA, they weren’t designed for Seismic resistance until Federal Emergency Management Agency FEMA started to do seismic evaluation and rehabilitation and suggested reinforcement methods. In this article we evaluate FRP sheet reinforcement.

Engineers are often faced with construction of pavement structures over soft and highly compressible subgrade. Such conditions render the structures unable to withstand the required design loads and susceptible to high settlements with associated excessive distress, leading to pavement damage. Because using imported quality fill to improve the load-bearing capacity of the subgrade has limited benefits, an alternative construction approach is needed to ensure the required strength of the soil structure is reached. The use of geosynthetics in soil to improve bearing capacity and stability offers a better alternative to imported fill. This research was conducted to determine the degree of improvement of the load-bearing capacity and reduction in settlement as a result of the geosynthetic reinforcement of soft clay overlain by granular material. Compression tests on the unreinforced clay subgrade and geosynthetic-reinforced two-layered soil composite were conducted at bench-scale using a Universal Compression Machine at the University of Cape Town Geotechnical Engineering Laboratory. The geosynthetic products used to reinforce the soil structure in this study included geogrids and geotextiles. The reinforcement layer was placed alternatively within the layer of granular material and at the interface of the soil and a range of fill thicknesses and depths of placement were tested to determine their influence on mobilized strength. The use of these composites could potentially lead to reduced construction costs as a result of less aggregate material used, an extension in the design life of the pavement structure and, consequently, a reduced necessity for maintenance work.

—One of the parameters required to evaluate the behavior of soil under loading is the coefficient of subgrade reaction which is widely used nowadays. To obtain this parameter there are many theoretical and laboratory relations, but one of the most effective and direct way to obtain this parameter is using plate load test. In present study using the FLAC3D the analysis of plate load test results in the case of loose and dense sandy soil were performed and the effect of chamber dimension on plate load test results are investigated. The obtained results from 30×30 cm ² plate load tests on 1×1×1 m ³ chamber show that the boundary conditions have not significant effect the results and therefore, the results of Plate Load Test Results (PLT) tests on chamber are applicable to in situ condition.

The contamination of groundwater by heavy metal, originating either from natural soil sources or from anthropogenic sources is a matter of utmost concern to the public health. Remediation of contaminated groundwater is of highest priority since billions of people all over the world use it for drinking purpose. In this paper, thirty five approaches for groundwater treatment have been reviewed and classified under three large categories viz chemical, biochemical/biological/biosorption and physico-chemical treatment processes. Comparison tables have been provided at the end of each process for a better understanding of each category. Selection of a suitable technology for contamination remediation at a particular site is one of the most challenging job due to extremely complex soil chemistry and aquifer characteristics and no thumb-rule can be suggested regarding this issue. In the past decade, iron based technologies, microbial remediation, biological sulphate reduction and various adsorbents played versatile and efficient remediation roles. Keeping the sustainability issues and environmental ethics in mind, the technologies encompassing natural chemistry, bioremediation and biosorption are recommended to be adopted in appropriate cases. In many places, two or more techniques can work synergistically for better results. Processes such as chelate extraction and chemical soil washings are advisable only for recovery of valuable metals in highly contaminated industrial sites depending on economical feasibility.► A number of groundwater treatment technologies for heavy metal remediation have been reviewed. ► Iron based techniques, Biological Sulphate Reduction and Permeable Reactive Barriers were most successful in the past decade. ► Biosorption is the emerging field mostly experimented in laboratories. ► More than one techniques can be coupled for site specific problems for better performance.

Geocell, which is one of the increasingly used geosynthetic materials in recent years, limits the lateral movement of the ground with its three-dimensional honeycomb structure. Thanks to this new technique, the cost of the soil improvement methods and the construction time are reduced. Even though various researchers have performed laboratory, field, and numerical studies, the factors affecting the working mechanism and performance of the geocells are not fully explained. With this review study, geocell history, usage areas, parameters affecting performance and working mechanism are explained.

The current research has investigated the soil quality status under dryland vegetation of Yabello district, Southern Ethiopia in which we should identify the nature and extent of salinity problem of the area for further research bases. About 48 soil samples were taken from 0-30, 31-60, 61-90 and 91-120 cm soil depths by opening 12 representative soil profile pits at 1.5 m depth. Soil color, texture, bulk density, Soil Organic Carbon (SOC), Cation Exchange Capacity (CEC), Na, K, Mg, Ca, CaCO3, gypsum (CaSO4), pH, Sodium Adsorption Ratio (SAR), Exchangeable Sodium Percentage (ESP) were analyzed. The dominant soil texture was silty-clay-loam. Bulk density varied from 1.1 to 1.31 g/cm 3. High SOC content was observed in 0-30 cm. The soil pH ranged from 7.1 to 8.6. The electrical conductivity shows indirect relationship with soil depth while CaCO3 and CaSO4 concentrations were observed in a direct relationship with depth. About 41% are non-saline, 38.31% saline, 15.23% saline-sodic and 5.46% sodic soils. Na concentration in saline soils was greater than Ca and Mg in all the soil depths. Ca and Mg contents were higher above 60 cm soil depth in non-saline soils. The concentrations of SO2-4 and HCO-3 were observed to be higher at the most lower depth than upper. SAR value tends to be higher at lower depths in saline and saline-sodic soils, but decreases at lower depth of the non-saline soils. The distribution of ESP above 60 cm depth was in an increasing order in saline and saline-sodic soils. The result of the research has shown the direction to which extent of salinity we should consider for the Commiphora plant species we want to grow on the area.

The paper under discussion (by Hassan et al. (2021)) presents a comprehensive set of experimental results from standard geotechnical laboratory tests performed on a low-plasticity clay soil (CL) amended with between 1% and 4% (by weight of dry
soil) of randomly distributed discrete polyethylene terephthalate (PET) and polypropylene (PP) fibers, each blended with the soil in two fiber lengths. However, the authors’ experimental investigation and results, while insightful, focus solely on the  geotechnical properties/performance of the clay soil–fiber mixtures, which are also compared with those of the unamended clay soil. That is, while the proposed soil reinforcement method is beneficial/smart from an engineering perspective, the authors do not present any discussion nor give any consideration to the potentially significant long-term environmental impacts that may arise from myriads of discrete plastic fibers mixed randomly with the soil in situ; an important aspect that motivated the discussers to pen this discussion contribution.

This paper presents a laboratory investigation into the resultant increase in shear strength and bearing capacity of locally sourced sand due to random inclusion of strips of high density polyethylene material from plastic shopping bags.A series of direct shear tests and bench-scape plate loadingtests was undertaken on soil-plastic composites of two selected sandy soils: Klipheuwel and Cape Flats sands. Strips of shredded plastic material were used as reinforcement inclusions at concentrations of up to 0.3% by weight. The effect of varying dimensions of the strips was investigated by using strip lengths from 15mm to 45 mm and strip widths from 6 mm to 18 mm. Soil strength parameters were obtained for
composite specimen from which analyses were carried out to identify the extent of soil improvement.Laboratory results obtained favourably suggest that inclusion of this material in sandy soils would be effective for soil reinforcement in geotechnical engineering.

In Germany, the annual economic damage attributable to mass movements is estimated at around €250 million. Studies indicate that there are relatively high losses, especially on traffic routes.
Preventive measures are necessary in order to prevent damage. This includes the installation of retaining structures in embankments to protect stability.
For the construction of stable slopes with adequate retaining structures, preliminary measurements must be made, which allow an assessment of the stability.
For this purpose, there are a variety of procedures that use different investigation methods. In this thesis, three analytical methods (Bishop, Janbu, General wedge method) and one numerical method (finite element method) were compared. The calculations were based on the example of the construction of a new cycle path in Bavaria.
The calculations were made using conservative and favourable soil parameters. Furthermore, soil parameters of the existing soil were determined by shear tests, which were included in additional calculations.
In the analytical methods, the decisive fracture area was either determined by varying the radius and the center coordinates or assumed to be in a certain area of the earth's body. 
The numerical approach of the finite element method, in contrast, made it possible on the one hand to calculate the failure mechanism and on the other hand to obtain information on displacements and deformations. For this purpose, however, further soil properties had to be determined or estimated and a correct material model had to be chosen to describe the plastic
behaviour of the soil.
The calculations showed that the geometry and the relative position of the different soil types within the earth mass are decisive for the shape of the sliding surfaces.
If a slope has simple geometries and the geological structure is uniform, numerical methods are sufficient to determine stability. If complex geometries are present and the plastic behaviour is to be tested, the application of numerical methods such as the finite element method is recommended. 
Moreover, concrete functional relationships between certain soil properties and stability were determined through several parameter studies.
An additional modelling of the project using photogrammetric methods enables further processing in the field of Building Information Modelling.

This study evaluated an improvement method based on static and dynamic tests for dune sand soil on the coast of Bandar Anzali city. This soil has very poor and insufficient mechanical performance for many construction projects as well as the potential for liquefaction. Short glass fibers have been used in this improvement method to reinforce the soil modified with nanoclay. The effects of simultaneously adding glass fibers and modified nanoclay at optimal weight percentages on the sand specimen were evaluated through static triaxial tests at consolidated drained conditions. The results showed that the simultaneous addition of glass fibers and nanoclay at lower confining pressures had more significant effects and was more useful for soil modification. The results indicated increases of more than 31% and about 23% in the peak deviatoric stress of the modified sand specimen at the confining stresses of 50 and 100 kPa, respectively, compared to the pure sand specimen. Furthermore, the modified sand specimen had a 20% reduction and a 50% increase in failure axial strain, compared to the pure sand specimen, under the static triaxial test at the confining pressures of 50 and 200 kPa, respectively; however, its failure axial strain did not change at the confining pressure of 100 kPa compared to the puresand specimen. The results of static triaxial tests showed that the simultaneous addition of glass fibers and nanoclay at the optimal weight percentages increased the cohesion of the sand specimen and did not change its internal friction angle. To investigate the effect of this improvement method on dune sand under dynamic loading, the cyclic liquefaction potential of pure and modified sand specimens was evaluated through cyclic triaxial tests under consolidated undrained conditions. The results showed a significant effect of sandy soil improvement on reducing its liquefaction potential. The number of loading cycles causing liquefaction was increased, by more than 5.5 times at the cyclic stress ratio of 0.27, by about 3 times at the cyclic stress ratio of 0.3, and finally, by more than 2 times at the cyclic stress ratio of 0.34 for the modified sand specimen compared to the pure sand specimen. By defining the cyclic stress ratio corresponding to liquefaction in the twentieth loading cycle as the specimen cyclic strength, the cyclic strength of the modified sand specimen was increased by more than 13% compared to the pure sand specimen. Based on the results of a series of different experiments conducted in this study, it was concluded that the simultaneous addition of glass fibers and modified nanoclay at their optimal weight percentages (0.5% and 1% by total dry weight of specimen, respectively) significantly improved many different resistance characteristics of dune sand soil from the Bandar Anzali coast, and using this composition can be considered as an effective and efficient way to improve this very special type of soil.

Agricultural activities can be important source of organic pollution. In agricultural intensive areas, organic chemicals have a high possibility of entering the water cycle, which could pose a potential risk to human health. Low-cost and high efficiency in-situ techniques instead of energy and money consuming ones to control agricultural organic micropollutants (Agro-OMPs) in aquatic system are extremely needed. In this paper, emerging Agro-OMPs were discussed focusing on their occurrence, pathways and risks. The mechanisms, dominant parameters and effectiveness of riverbank filtration, riparian buffer zone, constructed wetland and permeable reactive barriers for removing these pollutants are presented and discussed. Ecological succession in Riverbank Filtration (RBF) system is worth noticing for its stability maintenance. Riparian buffer zone (RBZ) should be explored more focusing on flexibility improvement and construction standardization. Constructed wetland (CW) is quite efficient on antibiotic resistance genes (ARGs) attenuation, but the risk of ARGs propagation still exist. Besides, more innovations should be made on combination, field-scale application and long-term evaluation of in-situ remediation techniques, which will provide references for agricultural water management and water quality improvement.

Loose soils normally are of weak bearing capacity due to their structural nature. Being exposed to heavy traffic loads, they would fail in most cases. To tackle the aforementioned issue, geotechnical engineers have come up with different approaches; one of which is making use of geosynthetic-reinforced soil-aggregate systems. As these polymeric reinforcements have highlighted economic and environmentally-friendly features, they have become widespread in practice during the last decades. The present research investigates the efficiency of four different types of these reinforcements in increasing the bearing capacity of two-layered soil sections using a series California Bearing Ratio (CBR) test. The studied sections are comprised of a 10 cm-thick layer of no. 161 Firouzkooh sand (weak subgrade) and a 10 cm-thick layer of compacted aggregate materials (base course) classified as SP and GW according to the United Soil Classification System (USCS), respectively. The aggregate layer was...

The contamination of groundwater by heavy metal, originating either from natural soil sources or from anthropogenic sources is a matter of utmost concern to the public health. Remediation of contaminated groundwater is of highest priority since billions of people all over the world use it for drinking purpose. In this paper, thirty five approaches for groundwater treatment have been reviewed and classified under three large categories viz chemical, biochemical/biological/biosorption and physico-chemical treatment processes. Comparison tables have been provided at the end of each process for a better understanding of each category. Selection of a suitable technology for contamination remediation at a particular site is one of the most challenging job due to extremely complex soil chemistry and aquifer characteristics and no thumb-rule can be suggested regarding this issue. In the past decade, iron based technologies, microbial remediation, biological sulphate reduction and various adsorbents played versatile and efficient remediation roles. Keeping the sustainability issues and environmental ethics in mind, the technologies encompassing natural chemistry, bioremediation and biosorption are recommended to be adopted in appropriate cases. In many places, two or more techniques can work synergistically for better results. Processes such as chelate extraction and chemical soil washings are advisable only for recovery of valuable metals in highly contaminated industrial sites depending on economical feasibility. Various technologies for remediating heavy metal contaminated groundwater has been reviewed. © 2011 Elsevier Ltd.

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http://www.sciencedirect.com/science/article/pii/S0301479711002064

Laboratory experiments were conducted to determine the distribution of various arsenic species in tailings and soils. Other specific goal of the tests were to evaluate the extraction efficiency of arsenic using alkaline or acid washing, to determine optimum operational parameters of alkaline washing, and to evaluate the arsenic precipitation of washing effluents by pH adjustment or ferric chloride addition. Alkaline washing using sodium hydroxide was found to be favorable in removing arsenic from tailings or soils having a higher portion of arsenic in the operationally defined crystalline mineral fraction of crystalline oxide and amorphous aluminosilicates. This is due to the ligand displacement reaction of hydroxyl ions with arsenic species and high pH conditions that can prevent readsorption of arsenic because predominant negatively charged crystalline oxides do not attract the negatively charged oxyanions. For tailings, sodium hydroxide had 10-20 times higher extraction efficiencies than hydrochloric- or citric acid. The optimum concentration of sodium hydroxide for soil washing was determined to be 200 mM for all samples, while the optimum ratios were 10:1 and 5:1 for tailings and field/river sedimentary soils, respectively. The washing effluent of river soil was effectively treated by adjusting pH to 5-6 with hydrochloric acid, resulting in arsenic concentrations of <50 μg l-1. In the case of field soil effluent, an addition of ferric chloride with a minimum mass ratio of 11 (Fe/As) was needed to reduce the arsenic below 50 μg l-1. © 2005 Elsevier Ltd. All rights reserved.

http://www.sciencedirect.com/science/article/pii/S0045653505000251

The reinforcement of metal matrix composite (MMC) has direct bearing on the quality of drilled hole. Based on the composition, the vibration amplitude varies as the hole is drilled. This in turn affects the quality of the drilled hole. The quality of drilled hole is also related to the stiffness of the component and behavior of material at high temperature. In order to suppress vibration amplitude, the damping coefficient can be increased to the extent possible. This often leads to achieving good quality of drilled hole. The MMC considered in this study is the aluminium silicon nitride. The base is aluminium 6061 with reinforcement being silicon nitride. In the experimentation, thrust force data, vibration data, temperature data of the composite component with increasing the percentage of silicon nitride are collected. The test component is analyzed in ANSYS WORKBENCH. Natural frequencies for different modes are recorded and specimen response is simulated for different percentage of silicon nitride. I. INTRODUCTION The factors are considered for indicating the quality of drilled hole are its inside diameter and surface roundness. These are influenced by the cutting conditions such as cutting speed, feed rate, tool material, geometry and the diameter of the tool. The quality of the drilled hole also depends on the dynamic properties like natural frequency of the component and stresses induced during drilling operation. The behavior of MMC plates resting on drilling machine during the drilling operation has wider interests. Dhavamani and Alwarsamy [1] investigates the drilling of aluminium silicon carbide (AlSiC) process by taking into account the effect of machining time on metal removal rate, surface roughness, volume fraction, surface energy, cutting speed, feed, diameter of cut and flank wear. In their work they attempt to establish a comprehensive mathematical model for correlating the interactive and higher-order influences of various machining parameters. Alakesh Manna and Kanwaljeet Singh [2] state that the machining of AlSiC materials with 10% of silicon nitride component is difficult due to the presence of reinforced SiC particulates in the aluminium matrix composite. Tsao and Hocheng [3] worked on the prediction and evaluation of thrust force and surface roughness in drilling of composite material using candle stick 10% of silicon nitride component tool. They establish a relation between the spindle speeds, feed rate, and drill diameter with the generated thrust force and surface roughness in operation of drilling. Jagadish and Ravindra [4] have considered vibration monitoring as the most widely used technique because most of the failures in the machine tool could be due to increased vibration level. Experiments were carried out using the condition monitoring instrument to measure vibration extremity for different spindle speed. From the numerical analysis and experimentation, it was found that the vibration velocity increases as the spindle speed and depth of the defect increases. [4] Umesh Gowda and Ravindra [5] carried out an experiment for optimization of process parameters in drilling AlSi3N4 metal matrix composite materials.

Treating marine clay is important for further purposed in construction and other infrastructure. Marine clay known as sort of clay found both in the littoral and in a few seaward ranges (S. Basackand R & D. Purkayastha, 2009). Base on the objective of this study, the sample will be classified based on AASTHO and USCS classification systems by using Atterberg limits test (liquid limit and plastic limit) and sieve analysis test, where Unconfined Compressive Strength test (UCS) and California Bearing Ratio test (CBR) tests were conducted to determine the strength before and after adding different percentages of lime and OPC cement.

In Poland, there is much experience with soil reinforcements and improvements by so-called "micro-blasts", the precisely applied and controlled underground explosions. This method appears to be very effective, unexpensive and fast. In the Netherlands, however, there is little experience with this method, although it might be beneficial in many projects.
This article aims to wake interest in the "micro-blast" soil improvement methods in the Netherlands, The authors present some successful applications in Poland and the tools to plan and apply the "micro-blasts" in the most effective way.

Agricultural activities can be important source of organic pollution. In agricultural intensive areas, organic chemicals have a high possibility of entering the water cycle, which could pose a potential risk to human health. Low-cost and high efficiency in-situ techniques instead of energy and money consuming ones to control agricultural organic micropollutants (Agro-OMPs) in aquatic system are extremely needed. In this paper, emerging Agro-OMPs were discussed focusing on their occurrence, pathways and risks. The mechanisms, dominant parameters and effectiveness of riverbank filtration, riparian buffer zone, constructed wetland and permeable reactive barriers for removing these pollutants are presented and discussed. Ecological succession in Riverbank Filtration (RBF) system is worth noticing for its stability maintenance. Riparian buffer zone (RBZ) should be explored more focusing on flexibility improvement and construction standardization. Constructed wetland (CW) is quite efficient on antibiotic resistance genes (ARGs) attenuation, but the risk of ARGs propagation still exist. Besides, more innovations should be made on combination, field-scale application and long-term evaluation of in-situ remediation techniques, which will provide references for agricultural water management and water quality improvement.

Methyl tertiary butyl ether (MTBE) belongs to the group of gasoline oxygenates and persistent environment contaminants, and shows potential for biodegradation in aerobic and anaerobic conditions, through application of pure microbial cultures. Presented research shows that indigenous bacterial isolates 6sy and 24p, selected from oil hydrocarbons-contaminated environments, were capable of utilizing MTBE as sole carbon and energy source. Based on 16S rDNA sequence analysis, bacterial isolates 6sy and 24p were identified as Staphylococcus saprophyticussubsp. saprophyticusand Pseudomonas sp., respectively. The MTBE biodegradation rate was affected by longevity of incubation period and initial MTBE concentration. After 3 weeks of incubation at 25°C in a dark, the removal rates of initial 25 and 125 ppm MTBE concentrations by Staphylococcus saprophyticus6sy were found to be 97, and 63%, respectively, while efficiency of Pseudomonas sp. in degradation of indicated concentrations was 96, and 40%, respectively. Both bacterial isolates were able to grow in MTBE-containing growth medium. Highest growth rate of bacterial isolates was observed at the end of incubation period. The presented results indicated the potential of these bacterial isolates in bioremediation of MTBE-contaminated environments.

The investigation of patellar tendon reflex involves development of a reflex hammer holder, kinematic data collection and analysis of patellar reflex responses using motion analysis techniques. The main aim of this research is to explore alternative means of assessing reflexes as a part of routine clinical diagnosis. The motion analysis system was applied to provide quantitative data which is a more objective measure of the patellar tendon reflex. Kinematic data was collected from 28 males and 22 females whilst subjected to a knee jerk test. Further analysis of kinematic data was performed to predict relationships which might affect the patellar tendon reflex. All subjects were seated on a high stool with their legs hanging freely within the capture volume of the motion analysis system. Knee jerk tests were applied to all subjects, on both sides of the leg, by eliciting hypo, hyper, and normal reflexes. An additional reinforcement technique called the Jendrassik manoeuvre was also performed under the same conditions to elicit a normal patellar tendon reflex. The comparison of reflex response between genders showed that female subjects generally had a greater response compared to males. However, the difference in reflex response between the left leg and the right leg was not significant. Tapping strength to elicit a hyper-reflex produced greater knee-jerk compared to the normal clinical tapping strength. All results were in agreement with clinical findings and results found by some early researchers. © 2010 IPEM.

http://www.ncbi.nlm.nih.gov/pubmed/21146440
http://www.sciencedirect.com/science/article/pii/S1350453310002705