Application of Vertical Reinforcement for Performance Enhancement of Reinforced Soil Under Seismic Loading

Reinforced soils have been widely used in geotechnical structures as a result of their satisfactory performance and cost effectiveness. A number of investigations have been carried out to find out the seismic deformation modes of reinforced soil walls with conventional horizontal inclusions. This study puts forward a new concept of soil reinforcement, applying vertical reinforcement together with conventional horizontal reinforcement. A key difference between the general practice and after insertion of vertical reinforcement is that the latter not only provides passive resistance against shearing due to making intact layers but also increases the strength and stability of the reinforced soil. The concept of soil reinforcement behaviour and its positive effects are analysed under static and seismic loads. The vertical reinforcement can be implemented by stitching horizontal reinforcing layers to each other. For this purpose, different techniques can be applied. Two practical and possible methods, proposed by the authors, are presented. Employing this technology can promote numerous benefits to the current industry of soil reinforcement

Case Study on the Influence of Transpiration on the Ground Behaviour

Bioengineering including native vegetation is an ancient method of improving the stability of slopes. In modern railway engineering, this technique is re-captured for increasing the soil stiffness and shear strength of sub-grade beneath rail tracks. A mathematical model for the rate of root water uptake has been developed considering ground conditions, type of vegetation and climatic parameters. The three independent features in the root water uptake model considered in detail are soil suction, root distribution, and potential transpiration. In order to establish a rigorous analysis for estimating the actual transpiration or root water uptake, the above mentioned factors have been quantified through relevant equations to develop the model. A two dimensional finite element approach has been employed to solve the transient coupled flow and deformation equations. In order to validate the model, an array of field measurements conducted at Miram site in Victoria, Australia and the data have been compared with the numerical predictions. The predicted results calculated using the soil, plant, and atmospheric parameters contained in the numerical model, compared favourably with the field and the associated laboratory measurements, justifying the assumptions upon which the model has been developed

A Comparative Study on Soil Stabilization Relevant to Transport Infrastructure using Bagasse Ash and Stone Dust and Cost Effectiveness

Soft ground improvement to provide stable foundations for infrastructure is national priority for most countries. Weak soil may initiate instability to foundations reducing their lifespan, which necessitates the adoption of a suitable soil stabilization method. Amongst various soil stabilization techniques, using appropriate admixtures is quite popular. The present study aims to investigate the suitability of bagasse ash and stone dust as the admixtures for stabilizing soft clay, in terms of compaction and penetration characteristics. The studies were conducted by means of a series of laboratory experimentations with standard Proctor compaction and CBR tests. From the test results it was observed that adding bagasse ash and stone dust significantly upgraded the compaction and penetration properties, specifically the values of optimum moisture content, maximum dry density and CBR. Comparison of test results with available data on similar experiments conducted by other researchers were also performed. Lastly, a study on the cost effectiveness for transport embankment construction with the treated soils, based on local site conditions in the study area of Assam, India, was carried out. The results are analyzed and interpreted, and the relevant conclusions are drawn therefrom. The limitations and recommendations for future research are also included. Doi: 10.28991/cej-2021-03091771 Full Text: PD

A Comparative Study on Soil Stabilization Relevant to Transport Infrastructure Using Bagasse Ash and Stone Dust and Cost Effectiveness

Soft ground improvement to provide stable foundations for infrastructure is national priority for most countries. Weak soil may initiate instability to foundations reducing their lifespan, which necessitates the adoption of a suitable soil stabilization method. Amongst various soil stabilization techniques, using appropriate admixtures is quite popular. The present study aims to investigate the suitability of bagasse ash and stone dust as the admixtures for stabilizing soft clay, in terms of compaction and penetration characteristics. The studies were conducted by means of a series of laboratory experimentations with standard Proctor compaction and CBR tests. From the test results it was observed that adding bagasse ash and stone dust significantly upgraded the compaction and penetration properties, specifically the values of optimum moisture content, maximum dry density and CBR. Comparison of test results with available data on similar experiments conducted by other researchers were also performed. Lastly, a study on the cost effectiveness for transport embankment construction with the treated soils, based on local site conditions in the study area of Assam, India, was carried out. The results are analyzed and interpreted, and the relevant conclusions are drawn therefrom. The limitations and recommendations for future research are also included

Parametric Study of Applied Stresses on Infiltration Modular Cells installed under Roads

Abstract Modular geocellular units are applicable for the prevention and minimisation of stormwater runoff and flooding as a sustainable and cost-effective solution of road applications for drainage. The integrated units buried are exposed to the dead loads and live loads emerging from the surrounding soil pressure, pore water pressure and surcharge. Thus, a computer program using MATLAB is developed for the assessment of the total vertical and lateral earth pressure exerting on the modules complying with the Australian Standards AS 467

Effects of salinity and sand content on liquid limit and hydraulic conductivity

Soil conditions of construction sites have become worse than ever due to the overpopulation in the metropolitan areas throughout the world. Likewise, the prevention of environmental risks due to individual activities is one of the most important subjects in the geo-environmental problems. Saline soils may induce several problems in geotechnical engineering projects such as infrastructure embankments, road construction and clay liners. Effect of the various concentrations of sodium chloride (NaCl) on several different soils including bentonite, kaolinite and fine sand mixtures has been evaluated. In addition, influence of salinity and the period of submergence on the hydraulic conductivity of soil samples collected from a certain area of east coast of India was investigated. The results show that the liquid limit of the mixtures generally decreases with an increase in the salt concentration. Liquid limit decreased significantly with an increase in NaCl concentration up to a certain level. However, a further increase in the concentration does not induce any significant decrease in liquid limit. Furthermore, the soil hydraulic conductivity increase with the salt concentration and with increase in the period of submergence, the hydraulic conductivity of the soil increases asymptotically

Flow Characteristics through Granular Soil Influenced by Saline Water Intrusion: A Laboratory Investigation

The coastal geoenvironment initiates saline water intrusion into the freshwater aquifers, producing a geohydraulic problem. Such intrusion not only contaminates the fresh groundwater resources, making them unsuitable for human use, but also alters the hydraulic conductivity of the aquifer materials, which affects the coastal groundwater flow, influencing the water resources planning and management. Past investigations reveal that the groundwater flow can be linear or nonlinear depending upon the hydraulic gradient. Thus, the coefficients of nonlinear hydraulic conductivities are affected by saltwater intrusion. The present study focuses on an in-depth laboratory investigation into the influence of saltwater submergence on the nonlinear flow characteristics through granular soil. The fine sand samples have been submerged under saline water of specified concentrations for a specific duration, and the alteration in their nonlinear geohydraulic properties has been studied. It is observed that the flow characteristics through fine sand are significantly affected by the period of submergence and saline concentration. Appropriate analyses of the test results are performed to interpret the experimental data, and relevant conclusions are drawn therefrom. The novelty of this study is an in-depth analysis of nonlinear flow characterization affected by saline water intrusion. Doi: 10.28991/CEJ-2022-08-05-02 Full Text: PD