Soft Soil Stabilization Research Articles

Experimental and numerical evaluation of sustainable application of steel slag as an alternative to gravel in compaction piles

The study investigates the application of steel slag as an innovative material for compaction piles in the stabilization of soft soils, offering an eco-friendly alternative to conventional gravel compaction piles (GCPs). Through a comprehensive series of laboratory tests, field experiments, and numerical simulations, this study evaluated the performance, environmental impact, and long-term behavior of steel slag compaction piles (SSCPs). The key findings revealed that steel slag not only provides immediate soil improvement comparable to gravel but also exhibits significant time-dependent increases in strength and stiffness. Standard Penetration Test (SPT) N-ratios (N1/N0, where N1 = N value after improvement and N0 = N value before improvement) were similar for soils reinforced with SSCPs and GCPs after 0 months, but were about 30 % higher in SSCP-reinforced soils after 3 months. This increase was attributed to the cementation of steel slags, suggesting that the compaction pile with increased stiffness due to cementation acts as a compaction pile with an increased area replacement ratio (α). Environmental assessments confirmed that steel slag meets regulatory standards for soil contamination, positioning it as a sustainable option. Settlement analysis after embankment construction showed reduced and more uniform settlements with SSCPs, suggesting superior load distribution capabilities. Finite element analysis compared the behavior of SSCP-reinforced soils at varying α and stiffness of compaction piles, confirming that the cementation of steel slag produces an effect equivalent to increasing α in uncemented piles, thus enhancing the reinforcement effect.

Soft soil stabilization using co-pyrolytic biochars from sewage sludge and Nymphaeale, an invasive plant biomass

This research addresses a significant gap in current literature by proposing an alternative to traditional carbon positive soil stabilizers by utilizing sewage sludge in conjugation with Nymphaeale, an invasive plant biomass derived co-pyrolytic biochars to stabilize the soft soil, with a focus on understanding strength gaining mechanism. Various combinations of sewage sludge and Nymphaeale biomass underwent thermogravimetric analysis in a nitrogen environment, suggesting 450°C as pyrolysis temperature for biochar synthesis. Soft soil, which is considered problematic for construction, was blended with five distinct dosages (0%, 5%, 7.5%, 10%, and 12.5%) of biochars (BC75:25, BC50:50, BC25:75) by weight and unconfined compressive strength values were examined over curing periods of 1, 7, 14, and 28 days. The stress-strain and failure behaviour of soil-biochar mixes varied depending on the type of biochar used. SBC25:75 mixes exhibited ductile behaviour, whereas SBC75:25 mixes showed comparatively brittle failure. Furthermore, unconfined compressive strength values of soil-biochar mixes increased 4–5 times with maximum strength achieved at 10% dosage of BC50:50. Biochar dosages led to a reduction in moisture content and an increase in alkalinity and conductivity of the mixes, facilitating the initiation of pozzolanic reactions. The combined findings from the various analyses suggested that the presence of free oxides of calcium in biochars disrupted the laminated structure of the soil and reacted with silica and other aluminum silicates, resulting in the densification of the structure and the formation of cementing mineral phases in the mixes. Overall, the research-work emphasizes the idea of creating novel environmentally friendly binders for soil stabilization through the utilization of waste materials.

Improvement of mechanical behavior of cemented soil reinforced with waste sisal fibers: An optimal selection and modification research

In response to escalating environmental concerns, this study explored the use of sisal fiber as a sustainable alternative to traditional cement or synthetic fibers for soft soil stabilization. An optimal selection test was conducted to determine the optimal sisal fiber characteristics and their impact on the mechanical performance of cemented soil. The findings indicated that incorporating sisal fibers into cemented soil inhibits crack propagation, thereby enhancing its strength and ductility. A significant improvement was achieved by incorporating optimal fiber parameters (content = 0.4 %, length = 11 mm) into the cemented-soil, the compressive strength reached 4.4 MPa (by 29.4 %). In addition, to further improve the work performance of sisal fiber-cemented soil (SFCS), alkaline and acetylation treatments were applied, respectively, to prevent volume instability and degradation of sisal fiber. The study also evaluated the effects of these modification methods on the physical properties of sisal fiber and the strength of sisal fiber-cemented soil (SFCS). The results showed that a 6 % NaOH treatment was determined to be the most effective modification method, reducing the moisture affinity of sisal fiber, improving fiber-matrix bonding, and consequently enhancing the mechanical properties of SFCS (by 18.7 %). However, it should be noted that an excessively high concentration may adversely affect fiber properties, negatively impacting the strength of SFCS (by up to 11.59 %).

Advancements in Soft Soil Stabilization by Employing Novel Materials through Response Surface Methodology

Stabilization using industrial by-products is presently gaining importance in the construction sector for improving the geotechnical characteristics of soft soils. The optimum dosage of stabilisers has become of great interest to experimenters in terms of improved strength, time, and economy for construction projects. This work presents the utilization of biomedical waste ash for improving the strength of soft soil. In this paper, response surface methodology (RSM) was adopted to determine the optimum combination curing period (C) and biomedical waste ash (BA) quantity for attaining the maximum unconfined compressive strength (UCS) of soft soil and to reduce the number of trial tests required. The response factors C and BA were varied from 0 to 14 days and 4% to 20%, respectively, and the experiments were conducted according to the experimental plan provided by the RSM design. Based on a Face-centred Central Composite Design (FCCCD), a mathematical equation was created for the experimental results. Analysis of variance (ANOVA) was used to determine the generated model’s significance, and the results indicated a statically significant model (p ≤ 0.05). The results revealed that the curing period imparts more influence towards strength improvement, and the optimum dosage was 19.912% BA, with curing of 14 days to yield a maximum UCS of 203.008 kPa. This optimization technique may be suggested to obtain a preliminary estimation of strength prior to stabilization.

Lightweight rPPU Eco-block Using Recycled Plastic (rP) and Polyurethane (PU) for Soft Subgrade Soil Stabilisation

The stability of the soil plays a crucial role in the safety and longevity of various civil engineering structures. However, problematic soil conditions, such as clay soil and peat soil, often pose challenges due to their high-water content, poor strength, low bearing capacity, and high compressibility. This research focuses on addressing these challenges by utilizing lightweight fill materials as an effective solution for backfilling applications. The study aims to investigate the characteristics and performance of a novel lightweight fill material using recycled plastic (rP) and polyurethane (PU) known as rPPU ecoblock. The eco-block is mainly fabricated using recycled plastic bottles, recycled plastic packaging, and polyurethane, offering a sustainable approach to waste management and construction materials. To achieve the research objectives, a series of experiments will be conducted. The strength and density of plastic bottles filled with recycled plastic packaging will be analyzed, providing insight into their mechanical properties. Furthermore, the water absorption and buoyancy of the lightweight rPPU eco-block are evaluated, considering its suitability for various construction scenarios. The research findings contribute to the understanding of the physical and mechanical characteristics of the rPPU eco-block, providing valuable information for its potential application as a backfill material. The compressive strength, water absorption, and buoyancy tests conducted per ASTM standards provide quantitative data on the eco-block's performance. The use of lightweight fill materials, particularly the rPPU eco-block, offers benefits such as reduced embankment self-weight, improved stability, and minimized environmental impact. Moreover, the recycling of plasticwaste contributes to the circular economy and aligns with sustainable development goals (SDG): SDG9 and SDG11. The results of this research provide valuable insights for engineers, construction professionals, and stakeholders involved in geotechnical and civil engineering projects.

Proximity Porosity and Crystallinity Analysis as Clay/Nickel Slag Characteristics for Material Stabilization Application

Slag nikel is a by-product of nickel ore smelting through the pyrometallurgical process, which contains silica (> 50 %). This suggests that nickel slag, possessing pozzolanic properties, which potentially to be used as a binding material in construction projects dealing with low soil bearing capacity, such as soil improvement for road foundation. Pozzolanic reactions are greatly influenced by the chemical bonds formed between the binding material and the soil, causing mechanical characteristic changes in the soil. This study aims to examine the effect of adding nickel slag to soft soil based on changes in its physical, mechanical and chemical properties. Physical and mechanical property tests were conducted according to ASTM standards, while the changes in chemical structure in the soil were analyzed based on X-Ray Diffraction (XRD) test results. In this study, nickel slag percentages of 3, 6, 9 and 12 % were used based on the weight ratio of clay soil, at optimum water content (wopt). Furthermore, the test specimens were cured for 14, 28 and 56 days to observe the effect of time on the increase of crystal phases in each variation. The results showed that the presence of nickel slag in the soil can affect its physical and mechanical properties. The nickel slag content in the soil of 3, 6, 9 and 12 % reduces the plasticity index by 16.69, 12.02, 8.86 and 6.38 %, respectively. Meanwhile, the density values increased by 10.97, 11.27, 11.68 and 12.01 kN/m3, respectively. The changes in physical and mechanical properties can be explained by the XRD analysis results, showing changes in the spectrum curve and peak intensity of X-Ray Diffraction in the soil with the addition of nickel slag. This explanation clarifies the transformation of the soil’s atomic structure from an amorphous state to a crystalline form, which is stabilized by nickel slag. HIGHLIGHTS The silica-rich nature of nickel slag offers a feasible alternative for chemical soil stabilisation The stabilization of soft soil with nickel slag results in a decrease in the plasticity index and an increase in density Immersion duration shows a changing response for the crystallinity index and porosity of the material GRAPHICAL ABSTRACT

Stabilization of soft soil with rice husk and coconut fibre

Stabilization of soft soil with rice husk and coconut fibre

Effects of oil palm mesocarp fibers on the physical and mechanical properties of expansive soils

Palm fiber is one of the favorable materials used in stabilization of soft soil in geotechnical engineering projects, nowadays due to its sustainability, less damage of environment, biodegradability, availability and cost-effectiveness in a context of widespread appeal to the world for return to nature by protecting the earth. On the other hand, expansive soils are renowned for their swelling-shrinkage property and these volumetric changes resultantly cause huge damage to civil infrastructures. Likewise, subgrades consisting of expansive soils instigate serviceability failures in pavements across various regions worldwide. This paper presents results of the laboratory evaluation of expansive soils stabilized with oil palm mesocarp fiber (OPMF), with a view to determine its suitability as flexible pavement construction material. The mixtures were subjected to British Standard heavy (modified Proctor) compaction energy to determine their strength characteristics. The samples were subjected to different tests to ascertain their index properties. Varying proportions of OPMF from 1% to 4% were incorporated into the soil samples and the effects were observed based on compaction and California Bearing Ratio (CBR) results. The control samples without inclusion of OPMF achieved the highest Maximum Dry Densities (MDD), the MDDs reduced linearly as the OPMF content increased. Consequently, the CBR values decreased with increase in OPMF. The reduction in MDD ranged from 20.28g/cm3, 18.5 g/cm3, 15.65 g/cm3, 12.53 g/cm3 as the OPMF increased from 1%, 2% to 3%, 4%. and the optimum moisture content remained almost unaffected due to high-absorbent nature of the fibers. With the inclusion of the OPMF, the CBR value under soaked conditions dropped from 5% to 1.8% rendering them very unsuitable for pavement subgrade. It was concluded that the presence of fiber depreciated the engineering properties of the earth materials. Direct application of OPMF in any part of road pavement has been dissuaded.

Efficient stabilization of dredged sludge with high water content using an improved bio-carbonation of reactive magnesia cement method

This study proposed an improved bio-carbonation of reactive magnesia cement (RMC) method for dredged sludge stabilization using the urea pre-hydrolysis strategy. Based on unconfined compression strength (UCS), pickling-drainage, and scanning electron microscopy (SEM) tests, the effects of pre-hydrolysis duration (T), urease activity (UA) and curing age (CA) on the mechanical properties and microstructural characteristics of bio-carbonized samples were systematically investigated and analyzed. The results demonstrated that the proposed method could significantly enhance urea hydrolysis and RMC bio-carbonation to achieve efficient stabilization of dredged sludge with 80% high water content. A significant strength increment of up to about 1063.36 kPa was obtained for the bio-carbonized samples after just 7 d of curing, which was 2.64 times higher than that of the 28-day cured ordinary Portland cement-reinforced samples. Both elevated T and UA could notably increase urea utilization ratio and carbonate ion yield, but the resulting surge in supersaturation also affected the precipitation patterns of hydrated magnesia carbonates (HMCs), which weakened the cementation effect of HMCs on soil particles and further inhibited strength enhancement of bio-carbonized samples. The optimum formula was determined to be the case of T = 24 h and UA = 10 U/mL for dredged sludge stabilization. A 7-day CA was enough for bio-carbonized samples to obtain stable strength, albeit slightly affected by UA. The benefits of high efficiency and water stability presented the potential of this method in achieving dredged sludge stabilization and resource utilization. This investigation provides informative ideas and valuable insights on implementing advanced bio-geotechnical techniques to achieve efficient stabilization of soft soil, such as dredged sludge.

Cementitous material based stabilization of soft soils by stabilizer: Feasibility and durabiliy assessment

To accurately assess the safety of excavation and its impact on deformation settlement in soft soil areas, it is essential to conduct stability analysis and investigate the solidification mechanism of improved soft soil. This study involved a comprehensive series of laboratory tests, such as direct shear, dry-wet cycles, scanning electron microscopy (SEM), and X-ray diffraction (XRD) tests, encompassing a wide range of working conditions. Based on the findings, an optimal construction scheme for solidifying the soil was proposed, utilizing data from the Zhuhai Tunnel project. The test results indicated that the curing time and proportion significantly influenced the shear strength of the amended soil. It was determined that a 10% cement and 9% stabilizer curing for 28 days represented the optimal proportion. The stabilizer primarily enhanced the shear strength by increasing the cohesion of the soil. Furthermore, the improved soil exhibited excellent stability even after undergoing seven dry-wet cycles. Additionally, microscopic analysis was conducted to explore the chemical reactions and solidification mechanism occurring between particles in the improved soft soil. The stabilizer induces the migration of water molecules to the soil surface and continuously supplies hydration to the cement, promoting its secondary hydration and generating more calcium silicate hydrate gel (C-S-H) and ettringite (AFt). The gelation and filling effects of the hydration products between particles resulted in a densified structure, thereby enhancing the mechanical strength and stability of the improved soil. This research offers valuable guidance for the application of soil improvement in construction and engineering projects in soft soil areas.

A Review: Soil Stabilisation Using Agricultural Waste and Cementitious Material

A Review: Soil Stabilisation Using Agricultural Waste and Cementitious Material

Evaluation of Dry Density for Black Cotton Soil Using Rice Husk Ash

Abstract: Stabilization is a broad term that refers to the various methods used to improve the engineering performance of a soil and its application in a variety of engineering works. Soil stabilisation is a major concern for civil engineers today, both for road construction and for increasing soil strength or stability, which reduces construction costs. Soil stabilisation is the chemical or physical modification of soil properties to improve the soil's engineering quality. The primary goal of soil stabilisation is to increase the soil's bearing capacity, resistance to weathering processes, and permeability. Due to the rapid growth of urbanization and industrialization, minimizing industrial waste. Because of the rapid growth of urbanization and industrialization, reducing industrial waste has become a major issue in recent years. To encounter this innovative and nontraditional research on waste utilization is becoming increasingly important. Soil improvement using waste materials such as slags, rice husk ash, and silica fume has been recommended from an environmental standpoint in geotechnical engineering. This paper examines the effects of blast furnace slag, fly ash, and micro silica added to black cotton soil to improve soil properties. In addition, this paper provides a review of the use of various solid waste materials for soft soil stabilisation. However, there are numerous methods and techniques available for stabilising these soils. This study describes how waste materials can be used to stabilise soft soil

Stabilization of Soft Clay Soil by Deep Mixing with Lime and Cement in the Presence of Salt Water

Stabilization of Soft Clay Soil by Deep Mixing with Lime and Cement in the Presence of Salt Water

The Sustainability of Using DuraCrete as Cement Additive to Estuarine Soft Soil Stabilization

Large areas of estuarine deposits exist on the coastal plains of the southeast Queensland coast with a countered depth of up to 30 m. These deposits are categorized as sediments that originated during the Holocene Age. The sediments have not been consolidated or subjected to considerable pressure since the end of the Ice Age. The structure of these deposits consists of large ratios of porosity, causing high soil compressibility, which lowers the bearing capacity of the soils. Therefore, the soils of the region cannot maintain sufficient support for construction loads, and consequent malfunctions could occur in short-term and long-term periods. The objective of this paper is to investigate the suitability of new soil stabilization additives in the southeast Queensland region and the optimum additive content of cementitious materials and an advanced mixing modifier branded as DuraCrete. A combination of Portland cement and DuraCrete was used as a soil additive. Three DuraCrete-to-cement ratios were used: 2%, 3%, and 4% by weight. Soil collected from the Port of Brisbane region was treated by adding the additives as a percentage of its weight; four percentages were considered: 10%, 20%, 25%, and 30% for each combination of additives. The performance of the treated soils was examined under unconfined compression after 28 days of curing. The results revealed that increases in the unconfined compressive strength were detected as DuraCrete was added to the mixtures. For 30% additives, increases of about 15%, 34%, and 17% were detected when DuraCrete was added as 2%, 3%, and 4%, respectively. The results also revealed that 3% DuraCrete content provided significant stabilization compared to 2% and 4% for 25% and 30% additive-treated soils; such behavior was also observed for the specimens of 25% content of additives. Additionally, DuraCrete can be considered a promising material that can be combined with cement to obtain the desired stabilization of soft soils.

Features of stabilization of soft soils at the base of emergency deformed buildings using finely powdered injection materials in low pressure mode

At present, the strengthening of the soil base is often performed by high-pressure injection - injection of a solution under pressure that exceeds the structural strength of the soil (hydraulic fracturing mode). High-pressure injection makes it possible to successfully solve various geotechnical problems, but it has a number of disadvantages, first of all, the uncertainty of the shape and size of injection bodies created in the soil mass, as well as the impossibility of predicting the final deformation and strength characteristics necessary for design. It should be noted that directly from the production of injection works in the uncontrolled hydraulic fracturing mode, unpredictable technological deformations (rise followed by uneven settlement) of the Objects are observed, the base of which is stabilized, as a result of which crack formation processes in above-ground structures and fragmentary destruction of load-bearing elements develop. The article considers the possibility of solving the problem of predictable increase in the mechanical properties of stabilized soils on the example of a pilot production site in the central region of St. Petersburg. The proposed method makes it possible to ensure the absence of technological deformations from the production of injection works by using the author's kinematic scheme for the production of works and the use of modern solutions based on fine binders in the impregnation mode with an element of soil microfracture, that is, in the mode of controlled hydraulic fracturing at a reduced injection pressure of the injection solution.

Ontology Framework for Sustainability Evaluation of Cement–Steel-Slag-Stabilized Soft Soil Based on Life Cycle Assessment Approach

Steel slag has become a promising supplementary cementitious material for soft soil stabilization. However, there is a lack of research on the integrated assessment of cement–steel-slag-stabilized soft soils (SCSs) from the performance, environmental, and economic perspectives. In this study, an ontology framework for the sustainable evaluation of SCSs was developed based on the life cycle assessment (LCA) approach, which combined a knowledge base with semantic web rules to achieve an automated decision design for soft soil stabilization, considering comprehensive benefits. The ontology framework was applied to a marine soft soil stabilization case to verify its scientificity and practicability and to evaluate the influence of the fineness, carbonation degree, and substitution ratio of steel slag on the sustainability of SCSs. The results show that, when compared to pure-cement-stabilized soil (S-C), using 10% and 20% of fine steel slag carbonated for 18 h (FSS-C-18h) as cement substitutes can significantly reduce carbon emissions and costs while achieving a similar strength performance as S-C, demonstrating the feasibility of steel slag as a sustainable supplementary cementitious material for soft soil stabilization.

Nano-modified cementitious binders reinforced with basalt fiber/polymer pellets as a stabilizer for weak soils

Constructing on soft clay entails engineering challenges, such as significant volumetric changes; hence, stabilizing such problematic soil is essential. Since using lime in stabilizing soil is not recommended in some regions (e.g., Manitoba, Canada) due to some environmental concerns, there is a pressing need to explore suitable alternatives. This study investigates the efficiency of stabilizing soft clay using nano-modified cementitious binders (cement, slag, and nano-silica), reinforced with a new class of fibers (basalt fiber pellets). The mechanical and durability properties of the mixtures have been tested in terms of California bearing ratio, unconsolidated–undrained triaxial stresses, and freezing–thawing resistance. Thermogravimetry and scanning electron microscope analyses were performed to interpret the bulk trends. The results showed significant improvement for soft clay specimens stabilized with the nano-modified cementitious binders and reinforced with the pellets. This demonstrates the potential of the proposed reinforced binders for field applications involving the stabilization of soft soils.

An Experimental Design Methodology to Evaluate the Key Parameters on Dispersion of Carbon Nanotubes Applied in Soil Stabilization

The incorporation of carbon nanotubes (CNTs) in the process of chemical stabilization of soft soil is only possible when they are dispersed adequately in the medium. The maximum compressive strength (qu max) and the secant undrained Young’s modulus (Eu 50) are usually used to characterize the behavior of soil stabilized with Portland cement. In the present study, soft soil was additivated with a CNT dispersion prepared in a surfactant solution. This information was then used to produce a model based on an experimental design strategy, which allowed us to relate qu max and Eu 50 with the CNT concentration and the surfactant hydrodynamic diameter and concentration. The Partial Least Squares (PLS) regression method was selected to perform the regression, given the significant collinearity among the input variables. The results obtained lead us to conclude that the CNT concentration is the most important factor and has a positive impact on the responses (qu max and Eu 50). The surfactant concentration and hydrodynamic diameter have a negative impact on the responses, but, curiously, when combined, the impact becomes positive. It means that these variables depend on each other. The results obtained show that it is possible to produce a statistical model for these parameters with good correlation coefficient (R2).

A Review on Stabilization of Soft Soils with Geopolymerization of Industrial Wastes

A Review on Stabilization of Soft Soils with Geopolymerization of Industrial Wastes

Study on the optimization and performance of GFC soil stabilizer based on response surface methodology in soft soil stabilization

Study on the optimization and performance of GFC soil stabilizer based on response surface methodology in soft soil stabilization