Soil Stabilization Research Articles

Remediation effect of walnut shell biochar on Cu and Pb co-contaminated soils in different utilization types

Biochar, with its dual roles of soil remediation and carbon sequestration, is gradually demonstrating great potential for sustainability in agricultural and ecological aspects. In this study, a porous biochar derived from walnut shell wastes was prepared via a facile pyrolysis coupling with in-situ alkali etching method. An incubation study was conducted to investigate its performance in stabilizing copper (Cu) and lead (Pb) co-contaminated soils under different utilization types. The biochar effectively decreased the bioavailable Cu (8.5–91.68%) and Pb (5.03–88.54%), while increasing the pH, CEC, and SOM contents in both soils. Additionally, the results of sequential extraction confirmed that biochar promoted the transformation of the labile fraction of Cu and Pb to stable fractions. The mechanisms of Cu and Pb stabilization were found to be greatly dependent on the soil types. For tea plantation yellow soil, the main approach for stabilization was the complexation of heavy metals with abundant organic functional groups and deprotonation structure. Surface electrostatic adsorption and cation exchange contributed to the immobilization of Cu and Pb in vegetable-cultivated purple soil. This research provides valuable information for the stabilization of Cu and Pb co-contaminated soils for different utilization types using environmentally-friendly biochar.

Impact of wetting-drying cycles and acidic conditions on the soil aggregate stability of yellow-brown soil

Impact of wetting-drying cycles and acidic conditions on the soil aggregate stability of yellow-brown soil

Stabilization of soft soil with rice husk and coconut fibre

Stabilization of soft soil with rice husk and coconut fibre

Study on environmental characteristics of sustainable biomimetic soil preparation and its application in gangue reclamation

To address the key challenges in achieving large-scale ecological reclamation of coal gangue in situ, this study utilized loess from a mining area in Northwest China to prepare a biomimetic soil. A new inorganic curing agent (ISA) was developed using coal-based solid waste and cement. The study investigates the influence of different ISA dosages and their interaction with Polyacrylamide (PAM) on the environmental characteristics of biomimetic soil, including geotechnical, ecological, and heavy metal stabilization properties. Results indicate that the addition of ISA significantly enhanced the geotechnical performance of the in-situ soil, with unconfined compressive strength exceeding 350 kPa when ISA content was above 6 %. Soil evaporation experiments and soil water characteristic curve tests demonstrated that a 6 % ISA dosage combined with 0.05 ‰ PAM could maintain soil's good water retention capability while preserving a bimodal pore structure. The biomimetic soil exhibited effective stabilization of heavy metals, including Pb, Zn, Cu, and As. The particles of PAM and the hydration products of ISA not only filled soil pores and increased soil strength but also adsorbed, encapsulated, and immobilized heavy metals. “Biomimetic soil-gangue” leaching test results confirmed that the gangue samples treated with biomimetic soil met the standards for Class III underground water in China regarding heavy metal leaching values. This study provides an effective solution for the large-scale in-situ disposal and resource utilization of gangue in Northwestern mining areas of China.

Potentials of SANBASE Soil Stabilizer for Rural Roads Application

Potentials of SANBASE Soil Stabilizer for Rural Roads Application

Improvement of Clay Soils Using Cement as a Road Pavement Sub Grade (Case Study: Kuta-Tanah Lot Road)

Abstract Clay soil processing using cement is widely done but it is difficult to find studies that fit this topic, because the case study conducted is on the famous transportation route, namely Jalan Kuta – Tanah Lot in Bali, Indonesia. Pavements at this location are often damaged. In the dry season the road here is often cracked, while in the rainy season there is a decrease in certain parts or potholes occur that endanger users. Therefore it is necessary to conduct an analysis. This research aims to obtain the right formula of the ideal mixture of cement and clay, through mechanical tests i.e. compressive strength. Some results that are in accordance with the research conducted have been contained in the literature review, especially density and compressive strength testing. The use of cement as a stabilizer in clay is successful, as well as for other types of soil. The method used is soil sampling directly at the site, then mixed cement with various variations (treatment). This study discusses the success of cement to stabilize clay soils, especially increasing compressive strength and decreasing plasticity index. According to the results obtained that using cement as a soil stabilizer shows significant strength results, especially in ideal mixtures. This research is believed to be able to answer the obstacles that exist in clay soils to function as sub grade.

Effects of riparian pioneer plants on soil aggregate stability: Roles of root traits and rhizosphere microorganisms

Pioneer plants are vital in stabilizing soil structure while restoring reservoir drawdown areas. However, uncertainties persist regarding the mechanism of pioneer plants to soil stability in these delicate ecosystems. This study aims to unravel the plant-soil feedback mechanisms from the roles of root traits and rhizosphere microorganisms. We conducted a mesocosm experiment focusing on four common pioneer plants from the drawdown area of Three Gorges Reservoir, China. Using the wet sieving methodology, trait-based approach and high-throughput sequencing technology, we explored soil aggregate stability parameters, plant root traits and rhizosphere microbial communities in experimental plant groups. The interacting effect of pioneer plant species richness, root traits, and rhizosphere microbial communities on soil aggregate stability was quantified by statistical and machine-learning models. Our results demonstrate that diverse pioneer plant communities significantly enhance soil aggregate stability. Notably, specific species, such as Cynodon dactylon (L.) Pers. and Xanthium strumarium L., exert a remarkably strong influence on soil stability due to their distinctive root traits. Root length density (RLD) and root specific surface area (RSA) were identified as crucial root traits mediating the impact of plant diversity on soil aggregate stability. Additionally, our study highlights the link between increased rhizosphere fungal richness, accompanied by plant species richness, and enhanced soil aggregate stability, likely attributable to elevated RLD and RSA. These insights deepen our understanding of the role of pioneer vegetation in soil structure and stability, providing valuable implications for ecological restoration and management practices in reservoir drawdown areas.

Soil Stabilization Using Rice Husk Ash and Sugarcane Bagasse Ash

Abstract: Soil stabilization has become a major issue in construction engineering and the researches regarding the effectiveness of using industrial wastes are rapidly increasing. The present experimental work briefly describes the suitability of the locally available Rice Husk Ash (RHA) and Sugarcane Bagasse Ash (SCBA) to be used in the local construction industry in a way to minimize the amount of waste to be disposed to the environment causing environmental pollution. The common soil stabilization techniques are becoming costly day by day due to the rise of cost of the stabilizing agents like, cement, lime, etc. The cost of stabilization may be minimized by replacing a good proportion of stabilizing agent using RHA. It will minimize the environmental hazards also. Addition of rice husk ash and cement decreases the maximum dry density and increases the optimum moisture content.

ON THE INFLUENCE OF EXOGENEOUS PROCESSES ON THE RESULTS OF MEASURING MOVEMENTS OF GEODESIC MARKINGS

The influence of exogenous processes on geodetic marks is multifactorial, and in modern observation practice there is no clear scientifically based system of engineering and geodetic forecasting of neotectonics influence on the results of repeated high-precision leveling, on the basis of which it would be possible to solve the issues of stability of depth, soil and rock leveling marks, as well as modeling the mechanism of influence of exogenous processes on the results of repeated leveling. Therefore, the study of their influence is an urgent task. The study is aimed at determining the influence of exogenous processes on the results of measurements of geodetic marks displacements during observations at local geodynamic polygons in the Kryvyi Rih region. The work performed has shown that the temperature factor is periodic in nature and therefore its influence on the stability of the reps also naturally varies over time: it changes linearly in the time interval March-May and September-November, sinusoidally in June-August, if divided into separate parts. Although, in general, the temperature change can be described as a sinusoid. A linear correlation has been established, but it should be noted that it can be broken by the imposition of a stronger factor that determines the dynamics of the movement of the rappers. There is no clear connection between temperature changes Δt and exceedances Δh in the time interval May-July. The intensive increase in temperature corresponds to the lowering of soil references, which is inconsistent with the general theory of their stability. The phase shift is more than two months, which indicates the influence of another, stronger factor than temperature on the stability of soil references. Periodic changes in atmospheric temperature cause thermal deformations of rocks, which, due to differences in thermal properties and temperature conditions of rocks, have a complex differentiated structure in space and time, which is manifested in heterogeneous vertical displacements of the references underlying these rocks. The revealed regularities of the temperature factor and the instability of the references caused by this factor made it possible to predict its value and recommend a scheme of time periods for field measurements in repeated cycles.

Use of Biopolymers as Soil Stabilizers: A Review

Abstract: Soil enhancement methods offer engineers solutions for addressing stability issues encountered during project execution. Rather than employing traditional soil treatment techniques, soil stabilization focuses on enhancing the inherent characteristics of the soil. Currently, polysaccharide biopolymers like xanthan gum, guar gum, welan gum, beta glucan, and chitosan are utilized in soil behavior enhancement to mitigate environmental concerns. Biopolymers show promise in improving soil shear strength and reducing subsidence potential at varying water contents. The effectiveness of treatment relies on factors such as soil composition and the specific biopolymer used.

Modifying Expansive Soil Characteristics with Xanthan Biopolymer Integration

Abstract: Expansive soils pose significant challenges in various engineering projects due to their tendency to swell and shrink with changes in moisture content. Traditional stabilization methods often come with environmental and economic drawbacks. This research paper explores the potential of xanthan biopolymer, a polysaccharide of microbial origin (Xanthomonas Campestris), as a sustainable and effective alternative for altering the engineering properties of expansive soils. Through laboratory experiments and analysis, the paper investigates the influence of xanthan biopolymer on key soil properties such as swelling behaviour, shear strength, and permeability. The findings provide insights into the feasibility and efficacy of using xanthan biopolymer for soil stabilization, offering a promising avenue for sustainable geotechnical engineering practices.

Plant diversity effects on soil multistability

Soil is the basis for life on Earth as we know it. Healthy and stable soil is a prerequisite for well-functioning terrestrial ecosystems and has, thus, been proposed to play a key role in plant diversity–ecosystem functioning relationships. The overall objective of this sub-project is to study multidimensional soil stability as affected by plant diversity in a long-term plant diversity experiment. We designed three coordinated work packages (WPs) to comprehensively assess soil multistability to environmental fluctuations and climate extremes by considering the biological, chemical and physical dimensions that are key for soil functioning. We will use all unique facilities and approaches of the Jena Experiment Research Unit by combining synthesis of long-term data in the Main Experiment and the ΔBEF Experiment with performing new soil analyses in the DrY Experiment, the ResCUE Experiment and a joint CoMic Experiment, to gain a better mechanistic understanding of plant diversity–ecosystem functioning relationships. In close collaboration with other sub-projects, we will assess biological, chemical and physical soil properties and stability indicators that will be used to calculate soil multifunctionality and multistability indices. In WP1, we will build on three unique datasets to explore short-term and long-term effects of plant diversity on the stability of soil (microbial) properties. In WP2, we will combine different datasets and approaches to explore if plant diversity effects on the magnitude and stability of soil properties increase with abiotic and biotic stresses. In WP3, we will combine measurements of the above-mentioned dimensions of soil stability to explore if plant diversity increases the stability of multiple soil properties under hot drought. This sub-project is at the heart of the Research Unit by testing the overarching hypotheses outlined in the Coordination Proposal of the Jena Experiment, contributing to all main experiments, sharing data and performing joint sampling campaigns with all sub-projects and, at the same time, introducing a novel concept of soil multistability as affected by plant diversity and climate extremes. We propose to use a combination of simple, high-throughput (e.g. bait-lamina test) and more sophisticated methods (e.g. extracellular polymeric substances analyses) to be able to investigate temporal dynamics of soil processes and their mechanistic basis. Taken together, the results of the three WPs will provide new insights into the stabilising mechanisms of soil properties in the long term and in relation to climate extremes through plant diversity.

Ecofriendly solidification of sand using microbially induced calcium phosphate precipitation

This study introduces microbiologically induced calcium phosphate precipitation (MICPP) as a novel and environmentally sustainable method of soil stabilization. Using Limosilactobacillus sp., especially NBRC 14511 and fish bone solution (FBS) extracted from Tuna fish bones, the study was aimed at testing the feasibility of calcium phosphate compounds (CPCs) deposition and sand stabilization. Dynamic changes in pH and calcium ion (Ca2+) concentration during the precipitation experiments affected the precipitation and sequential conversion of dicalcium phosphate dihydrate (DCPD) to hydroxyapatite (HAp), which was confirmed by XRD and SEM analysis. Sand solidification experiments demonstrated improvements in unconfined compressive strength (UCS), especially at higher Urea/Ca2+ ratios. The UCS values obtained were 10.35 MPa at a ratio of 2.0, 3.34 MPa at a ratio of 1.0, and 0.43 MPa at a ratio of 0.5, highlighting the advantages of MICPP over traditional methods. Microstructural analysis further clarified the mineral composition, demonstrating the potential of MICPP in environmentally friendly soil engineering. The study highlights the promise of MICPP for sustainable soil stabilization, offering improved mechanical properties and reducing environmental impact, paving the way for novel geotechnical practices.

Utilisation of biomass ash after high-temperature treatment for strengthening purple soil under various curing conditions

As a renewable energy source, biomass has the potential to replace non-renewable, fossil fuels. However, the disposal of the waste biomass ash (generated during energy generation) needs to be studied. While prior studies attempted to utilise composite additives containing biomass ash for soil, the introduction of other additives, such as cement, was an environmental burden. By employing biomass ash composition as the sole additive for strengthening purple soil under various curing conditions using high-temperature treatment, this study maximised its utilisation. The results showed that the unconfined compressive strength (UCS) varied across different curing conditions as the biomass ash content increased. After high temperature treatment at 800 ℃, the biomass ash consistently reinforced purple soil under all the curing conditions. However, the biomass ash stabilisation mechanism differed between dry and humid curing conditions. Under dry curing conditions, the UCS increase depended on the cementing effect of soluble salt and/or insoluble calcite; under humid curing conditions, the UCS change was attributed to the damage to clay minerals, contact mode, and cementing effects of multiple components. Therefore, the 800 ℃ temperature-treated biomass ash can be used alone to reinforce purple soil, inhibiting the soil-water loss. This study presents a novel avenue for utilising waste, biomass ash, with considerable implications for environmental protection and soil stabilisation.

Predictive modelling of strength characteristics of stabilized medium expansive soils

This research explores the use of Artificial Neural Network (ANN) modeling to predict the Unconfined Compression Strength (UCS) of stabilized medium expansive soil, aiming to optimize the parameters influencing soil stabilization. A database comprising 240 data points was compiled from laboratory tests involving seven input parameters: Stabilizers content (SCBA & WMD), Curing Period (CP), Liquid Limit (L.L), Plasticity Index (PI), Specific Gravity (Gs), and Free Swell (FS). ANN modeling, employing Levenberg-Marquardt algorithms, demonstrated successful UCS prediction. Increasing the number of neurons improved model accuracy, with optimum results achieved with 14 neurons. With 14 neurons for LMA, the R and R² value reaches 0.99, 0.98 Moreover, plots between experimental and predicted values shows strong correlation as majority of predicted UCS is closed to line of fit. Also error shows large count of data points closed to line of zero error. Sensitivity analysis highlighted SCBA, WMD, CP, L.L, and P.I as significant contributors to UCS prediction, emphasizing their importance in soil stabilization. The study underscores the effectiveness of ANN modeling in predicting soil strength and recommends 4% SCBA and 20% WMD for optimal stabilization. Overall, this research presents a comprehensive approach to predicting UCS in stabilized expansive soil, offering insights into parameter optimization and model enhancement for future geotechnical applications.

Organizing a global list of cyanobacteria and algae from soil biocrusts evidenced great geographic and taxonomic gaps.

Biocrusts determine soil stability and resiliency, with a special role played by oxygenic photoautotrophic microorganisms in these communities. We evaluated temporal and geographic trends in studies focused on these microorganisms in biocrusts. Two databases were surveyed to obtain scientific articles published from 1998 to 2020 containing the terms 'biocrusts,' 'algae,' and 'cyanobacteria.' Although interest in biocrusts has increased recently, their ecological importance is still little explored. The scientific articles that mentioned a species list of cyanobacteria and/or algae revealed a very heterogeneous geographic distribution of research. Biocrusts have not been explored in many regions and knowledge in the tropics, where these communities showed high species richness, is limited. Geographic gaps were detected and more detailed studies are needed, mainly where biocrust communities are threatened by anthropogenic impacts. Aiming to address these knowledge gaps, we assembled a taxonomic list of all algae and cyanobacteria found in these articles, including information on their occurrence and ecology. This review is an updated global taxonomic survey of biocrusts, which importantly reveals their high species richness of oxygenic photoautotrophic microorganisms. We believe this database will be useful to future research by providing valuable taxonomic and biogeographic information regarding algae and cyanobacteria in biocrusts.

A review on Gymnosporia rothiana of its botanical, ecological, and medicinal significance

Gymnosporia rothiana, also known as "Konkan Katai" or "Roth's Spike Thorn," is a rare and endangered plant species in Maharashtra, India. Its botanical description includes thorny branches, elliptical leaves, and small white flowers. Ecologically, it supports habitat formation, erosion control, and biodiversity. Traditional healers use Gymnosporia rothiana for its anti-inflammatory, digestive, and febrifuge properties, highlighting its cultural significance in indigenous medicine. Gymnosporia rothiana, a valuable botanical resource with ecological, cultural, and medicinal importance, can be harnessed for human health and biodiversity conservation in Maharashtra, India, through research, conservation efforts, and advancements in phytochemical analysis, pharmacological studies, and clinical trials.In the rough and tumble of Maharashtra, India, Gymnosporia rothiana, also called "Konkan Katai" or "Roth's Spike Thorn," is a botanical gem. This essay provides a thorough analysis of Gymnosporia rothiana, including its ecological importance, traditional therapeutic use, intricate botanical details, and potential directions for further study and preservantion. The botanical description clarifies Gymnosporia rothiana's remarkable characteristics, which include its exquisite white blooms, elliptical leaves, and thorny branches. In terms of ecology, this plant is a cornerstone in its natural environments, helping to maintain soil stability, reduce erosion, and enhance biodiversity in the arid conditions of rocky plateaus and scrub woods. Gymnosporia rothiana is highly respected in traditional medicine, where it has been used for centuries by healers to treat a wide range of conditions. Gymnosporia rothiana represents a complex tapestry of medical history profoundly embedded in Maharashtra's cultural past, from its supposed anti-inflammatory and digestive capabilities to its function infever control and woundhealing. In the future, there may be more opportunities to explore the pharmacological potential and complex biochemistry of Gymnosporia rothiana. Through phytochemical analysis, pharmacological investigations, and clinical trials, scientists want to uncover the medicinal benefits concealed in this remarkable plant, therefore facilitating the development of evidence-based herbal remedies and environmentally sound conservation tactics.

Effect of Wetting and Drying Cycle on the Behavior of Teff Straw Ash-Stabilized Expansive Soil

This study explores the impact of wetting and drying cycles on teff straw ash-stabilized expansive soil, with a focus on enhancing its mechanical properties for road subgrade applications. Expansive soil, characterized by continuous swell and shrink behavior, undergoes cyclic testing to establish equilibrium and critical density. The mitigating effects of teff straw ash on soil damage and its influence on expansive soil’s mechanical attributes are investigated. Laboratory results classify natural expansive soil as A-7-5 and CH according to AASHTO and USCS standards, respectively. Using a one-dimensional odometer apparatus, six wetting–drying cycles are conducted on teff straw ash-stabilized expansive soil to observe its behavior at equilibrium. Scanning electron microscopy reveals a disordered bond between soil particles and teff straw ash, intensifying with increased wetting–drying cycles. X-ray diffraction analysis is performed on samples subjected to different curing times, indicating heightened cation exchange and pozzolanic reactions as curing duration increases, thereby reducing soil expansiveness. A 96-hr socked California Bearing Ratio (CBR) test assesses subgrade strength. The CBR values for natural soil fall below the Ethiopian Road Authority (ERA) standards for low-volume roads. In contrast, expansive soil stabilized with teff straw ash at 10%, 15%, and 20% exhibits substantial increases in CBR values (3.7, 6.7, and 8.9, respectively), meeting the ERA standards. This suggests that teff straw ash stabilization renders expansive soil suitable for low-volume road subgrades, aligning with ERA standards. This comprehensive study provides valuable insights into the potential use of teff straw ash as an effective stabilizer for expansive soils, offering sustainable solutions for road construction in regions characterized by expansive soil challenges.

The impact of Ethiopian Green Legacy Initiative (GLI) on landscape functionality and plant species diversity in Lake Hawassa watershed, Ethiopia

AbstractAs one of the responses to the global commitments against climate change, the Ethiopian Government launched a nationwide Green Legacy Initiative (GLI) in 2019, which largely focused on forest tree plantations with some inclusion of fruit trees. Despite its tremendous efforts and investments, its effectiveness and impacts have not been studied. This paper attempted to address this necessity by conducting a cross‐sectional quasi‐experiment in three randomly selected woredas/districts of Lake Hawassa Watershed from August 20 to September 2, 2023. The research hypothesized the likely impacts of GLI on four dependent variables (hydrological regulation, soil stability, nutrient cycling and plant species diversity). To achieve this, the research considered the two variants of GLI practices (plantation with and without soil and water conservation measures) and the corresponding control sites. Having three sites and three treatments with five replications, the study involved a total of forty‐five quadrats of the same size (20 m × 20 m). The first three parameters were analysed using the landscape functionality analysis method, while the fourth employed Shannon's diversity index. Results of ANOVA showed that, on average 87% of randomly selected quadrats were found to significantly improve the local hydrology (runoff potential) (≈ 83.3% with Av. p = 0.012), soil stability (≈100% with Av. p = 0.002), nutrient cycling (≈83.3% with Av. p = 0.017) and plant species diversity (≈83.3% with Av. p = 0.012). The research revealed positive results from the Ethiopian Green Legacy Initiative. The small number of samples is acknowledged as a limitation of the research.

Geotechnical Properties of Fly Ash Blended Expansive Soil: A Review

Fly ash, an industrial byproduct, is used as both a building material and a soil stabilizer due to its pozzolanic properties. Moreover, it is challenging to extrapolate the results based on an inadequate amount of laboratory data because of the non-homogeneous character of the soil and the diversity in the chemical properties of fly ash. This review article fills in the gaps by providing an overview of the existing data related to the geotechnical characteristics of expansive soil stabilized with fly ash. The chemical composition of fly ash is provided in terms of oxides of various elements to help identify the kinds produced in different nations. Additionally, information about the physical and geotechnical characteristics of fly ash blended expansive soil is provided in order to comprehend the influence of the fly ash's chemical composition and the expansive soil's fines percentage. While the geotechnical property comprises Atterberg's limit, compaction, UCS, shear strength, free swelling index, CBR, and consolidation, the physical property includes specific gravity and durability. Shear modulus, damping ratio, and Poisson's ratio are used to describe the dynamic properties of the modified expansive soil. The published data in this field and the research gap will be identified by the researchers with the aid of this article. Doi: 10.28991/CEJ-SP2024-010-06 Full Text: PDF