Soil Stabilization Research Articles

Mineralogical Impact on the Compaction of Residual Gabbro Soils in the Construction of Platinum Tailings Storage Facilities

AbstractOver the past decade, there have been 45 tailings storage facility (TSF) disasters worldwide resulting in fatalities, serious environmental damage, and the destruction of entire ecosystems. These failures often stem from substandard design or operational practices. Many TSFs are constructed in regions associated with intrusive mafic rocks such as gabbro, norite, pyroxenite, and anorthosite, which are commonly found alongside platinum group metals in areas like the Bushveld Igneous Complex in South Africa and the Great Dyke in Zimbabwe. The stability of these structures can be significantly influenced by the residual soils present at the construction sites. Residual soils, both cohesive and non-cohesive, contain varying quantities of different minerals, which can impact the compaction characteristics and, consequently, the stability of the TSF foundations. Cohesive soils rich in clay minerals, such as kaolinite and smectite, exhibit properties that can hinder effective soil compaction. The expansive nature of smectite due to its ability to absorb large amounts of water and host free exchangeable cations counteracts the compaction process, reducing soil stability. Soil compaction is a complex process influenced by several factors, including compaction effort, method, water content, particle size distribution, and mineralogy. This study aimed to analyse these factors using a series of laboratory tests, including foundation indicators, MOD AASHTO compaction testing, and X-ray diffraction analysis, on residual soils from two TSF construction sites. The findings revealed that soils with high clay content tend to retain more water and have a higher optimum water content, adversely affecting their compaction properties. This study highlights the critical need to consider the mineralogical composition and weathering effects of residual soils in the design and construction of TSFs. By improving our understanding of these factors, we can enhance the stability of TSF foundations, reducing the likelihood of future failures. The insights gained from this research highlight the importance of thorough geotechnical assessments in the successful design and maintenance of TSFs.

Impact of Nano-SiO2 on the Compressive Strength of Geopolymer-Solidified Expansive Soil

Expansive soil is widely distributed and often needs to be improved for engineering and construction needs. Using blast furnace slag and fly ash as precursors and NaOH as an alkali activator, a geopolymer was prepared to solidify expansive soil, and the effect of nano-SiO2 on the compressive strength and water stability of the geopolymer-solidified expansive soil was further studied. The effects of alkali addition ratio, nano-SiO2 addition ratio, and curing agent addition ratio on the unconfined compressive strength and water stability of the cured soil were studied through unconfined compressive strength tests, and the curing mechanism was analyzed by electron microscopy scanning. The experimental results showed that the unconfined compressive strength and water stability of geopolymer-stabilized soil first increased and then decreased with an increase in alkali activator dosage. The optimal dosage of alkali activator was found to be 12.5%. Furthermore, it was found that adding nano-SiO2 can further enhance the strength and water stability of solidified soil. When the content of nano-SiO2 was 3%, the unconfined compressive strength was increased by 15%. With an increase in the content of nano-SiO2 doped polymer (GFNS), the unconfined compressive strength and water stability of the solidified soil showed a trend of first increasing and then decreasing, reaching a peak at a content of 20%. The cementitious materials, such as hydrated calcium silicate and hydrated calcium silicate aluminate, generated by the reaction between nano-SiO2 and geopolymer played a role in bonding and filling in the solidified soil. Under the joint action of the two, the structural arrangement between the solidified soil particles became more compact, which improved the strength of the solidified soil.

Assessment, identifying, and presenting a plan for the stabilization of loessic soils exposed to scouring in the path of gas pipelines, case study: Maraveh-Tappeh city

Dealing with collapsible soils consistently presents a crucial challenge for geological and geotechnical engineers. Loess soil is among the most widely recognized types of collapsible soils, covering approximately 10 % of the Earth's land surface. Loessic soil is a sedimentary deposit primarily composed of silt-size grains, loosely bound together by calcium carbonate. In Iran, approximately 17 % of Golestan province is covered by silty, clayey, and sandy loesses, primarily composed of loessic soil. Additionally, several energy transmission lines in this province traverse these loess-covered areas. Based on the reports from Golestan Gas Company experts, the scouring of gas pipeline channels in various regions, such as Dashli-Alum in Maraveh-Tappeh city, causes significant risks in the traffic roads and is one of the most critical issues facing this company. This research assessed the dispersion and collapse potentials of loess soil using a range of field exploration and laboratory testing methods. These methods included atomic absorption spectroscopy, the double hydrometer, scanning electron microscope photography, wavelength-dispersive X-ray fluorescence spectrometry, and consolidation tests. The results indicate that soil collapsibility was acquired as one of the components of the scouring phenomenon occurrences. To achieve an optimal solution, the effectiveness of the chemical stabilization method involving cement, bentonite, micro-silica, and synthesized nano‑titanium additives was evaluated through an oedometer, Atterberg limits, uniaxial compression, and direct shear tests. Additives dry mixing of cement and nano‑titanium were obtained as the optimal stabilization solutions against scouring compared to other additives. However, considering the environmental impacts of cement production and use, nano‑titanium presents a more environmentally sustainable option due to CO2 absorption and reduced damage potential to vegetation.

Evaluation of geotechnical, mineralogical and environmental properties of clayey soil stabilized with different industrial by-products: A comparative study

The utilisation of soil stabilization techniques employing binders like lime or cement enables the use of soils that are classified as disposable, thereby reducing the need for landfills and the consumption of natural resources. However, the production of lime and cement results in significant CO2 emissions. Therefore, the application of industrial by-products (IBP) for stabilizing expansive soils presents an opportunity to minimise the use of traditional binders. This study investigates the geotechnical, mechanical, mineralogical, and environmental properties of four IBP (biomass bottom ash, biomass fly ash, steel slag, and mixed recycled aggregate) combined with a silica-based nanomaterial for road layer applications. The technical feasibility of the use of IBP was demonstrated, especially in combination with nanomaterials, allowing a 66 % reduction in the percentage of added lime, obtaining significant improvements with minimal plasticity and swelling index and bearing capacity CBR values higher than 25 %, applying BBA, BFA and SS. An environmental assessment of leachate analysis was performance, showing an immobilization of heavy metals that makes the application of IBP feasible. In addition, a life cycle analysis study showed the environmental benefits of applying IBP, such as a 50 % reduction in CO2 emissions due to the reduction of lime, resulting from the use of these materials, thus promoting more sustainable economic models.

Lime Stabilization of Tropical Soil for Resilient Pavements: Mechanical, Microscopic, and Mineralogical Characteristics.

Lime stabilization is a sustainable technique due to its use of local materials, increased durability, reduced maintenance, and improved resistance to water action. This paper examines the impact of lime stabilization on the mechanical, microscopic, and mineralogical properties of a tropical soil. Two types of lime, calcitic and dolomitic, were tested at 3% and 5% by weight. Compressive, indirect tensile and flexural test results and statistical analysis revealed that calcitic lime mixtures had higher strength and stiffness, whereas dolomitic lime mixtures exhibited greater deformability with higher tensile strain at break. Scanning electron microscopy indicated that the soil's porous matrix closed within 7 days for both lime types due to flocculation, with increased matrix interlocking over time. The calcitic lime mixture developed a more closed matrix compared to the dolomitic lime, which showed weaker cementing. X-ray diffraction analysis indicated higher consumption of clay minerals and a notable reduction in calcium hydroxide peaks in the lime-treated soils. The study concludes that calcitic lime provides better pavement performance for stabilizing the soil, enhancing its engineering properties while also being sustainable by reducing the need for raw material extraction and improving resilience to climate-related issues such as floods.

A novel test set up to study three-dimensional electrokinetic dewatering of dredged soil

The dredged soil obtained from maintenance activities of water bodies has emerged as a potential alternate fill material for infrastructure development. However, dredged soil requires stabilization due to high initial water content, low shear strength and high compressibility. Among several methods, stabilization of dredged soil by using electrokinetics is one of the effective ground improvement techniques that uses electric field to dewater and strengthen the soil. In this context, a series of experiments were conducted on dredged soil by using a combination of electrokinetic treatment with and without 6 kPa seating pressure (viz., low surcharge). A customized and patented electrokinetic dewatering (EKD) test set up was used for the three-dimensional electrokinetic treatment of soil. The potential difference (in the range of 6 V–48 V) within the soil was achieved by inserting stainless steel pipes of 21.4 mm outer diameter, 1.2 mm thickness, and 170 mm length. Two control tests (with and without seating pressure of 6 kPa) also were performed to understand the effectiveness of EKD. From the study, up to 1057% and 427% increase in dewatering was noted in EKD tests due to application of 24 V (optimum voltage noted in EKD tests) as compared to control tests, without and with seating pressure, respectively. Further, seating pressure with EKD resulted in effective control of crack formation in the dredged soil and uniform improvement in shear strength along the depth (up to 95 kPa). The combination of low surcharge with EKD, adopted in the study, is also expected to yield lower differential settlement, and hence better performance of geotechnical structures built on improved dredged soil. The novel 3-dimensional patented EKD test setup with Arduino-programmed automatic water pumping enables collecting and accurately measuring dewatered effluent volume, performing cone penetration tests on undisturbed soil, and collecting soil samples for determination of water content/physiochemical properties from different locations. Overall, the developed EKD setup can be utilized for evaluating the effectiveness and adopting real-time progress management for EKD or other ground improvement methods, and remediation of sludge, mine tailings, dredged sediments, and contaminated soils.

Effects of Long-Term Fenced Enclosure on Soil Physicochemical Properties and Infiltration Ability in Grasslands of Yunwu Mountain, China

Fenced enclosures, a proven strategy for restoring degraded grassland, have been widely implemented. However, recent climate trends of warming and drying, accompanied by increased extreme rainfall, have heightened soil erosion risks. It is crucial to assess the long-term effectiveness of fenced enclosures on grassland restoration and their impact on soil physicochemical properties and water infiltration capacity. This study investigated the effects of enclosure duration on soil organic matter, aggregate composition and stability, and infiltration capacity in Yunwu Mountain Grassland Nature Reserve, comparing grasslands with enclosure durations of 2, 14, 30, and 39 years. Results showed that grasslands enclosed for 14, 30, and 39 years had infiltration rates increased by 20.66%, 152.03%, and 61.19%, respectively, compared to those enclosed for only 2 years. After 30 years of enclosure, soil quality reached its optimum, with the highest root biomass, soil organic matter, aggregate stability, and a notably superior infiltration rate. The findings suggest that long-term fenced enclosures facilitate grassland vegetation restoration and enhance soil infiltration capacity, with the most significant improvement observed at the 30-year enclosure milestone, followed by a gradual decline in this effect.

Stabilization of Lateritic Soil using Fly Ash Based Geopolymer

Stabilization of Lateritic Soil using Fly Ash Based Geopolymer

Influence of Anisotropic Consolidation on the Instability of Loose Granular Soils Under Undrained and Drained Loading

Previous studies, mostly experimental, have reported conflicting observations on the effect of the initial anisotropic consolidation stress ratio (η<sub>0</sub>) on the stress ratio at the onset of instability (η<sub>f</sub>) for drained and undrained loading that involve static liquefaction. They indicate that as η<sub>0</sub> increases, η<sub>f</sub> could decrease, increase, or remain invariant, albeit without providing potential mechanistic factors. In this study, the anisotropic critical state theory (ACST) is used to investigate potential factors, including compressibility, state, and fabric anisotropy, that can explain the influence of η<sub>0</sub> on η<sub>f</sub> under undrained and drained loading. The assessments consider numerical simulations with the ACST-based SANISAND-F model, insights from SANISAND-F based instability criteria, the instability surface concept, and available experimental observations. Our findings show that compressibility and fabric anisotropy (and its evolution) are key factors in explaining the influence of η<sub>0</sub> on η<sub>f</sub>. In particular, the results show that if fabric evolution is not substantial, an increase in η<sub>0</sub> decreases η<sub>f</sub> for materials with significant compressibility, whereas the effect of η<sub>0</sub> in low compressibility materials is minimal. On the other hand, for materials that promote fabric evolution, the results suggest that the effect of fabric changes counteract compressibility effects, potentially increasing η<sub>f</sub>.

Enhancing the stability of soil contaminated with fluoride through the utilization of pristine and aluminium-impregnated biochar: a comprehensive mechanistic approach.

The effect of trivalent metal-modified biochar on the stability and mitigation of fluoride ions (F-) in contaminated soils remains largely unexplored, despite biochar's extensive application in F--contaminated soil. The mineral metal-modified biochar has the potential to serve as an efficient solution for soil contaminated with F-. In this study, pristine-pinecone biochar (P-BC) and AlCl3-modified pinecone biochar (A-BC) were synthesized and then utilized to remediate the soil that had been contaminated with F-. Both P-BC and A-BC efficiently immobilized F- within the contaminated soil. Further examinations through sequential extraction procedure and subsequent analysis using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and elemental dot mapping demonstrated a transformation of F- into a more stable state by A-BC treatment of the contaminated soil. This implies that A-BC may possess the capacity to function as an efficient ameliorant for immobilizing F- within the soil.

Assessing the potential of horsetail ash as a sustainable additive in infrastructure materials through ignition testing

This study assesses the application of horsetail ash as a sustainable soil stabilizer additive in infrastructure materials, highlighting the significance of environmentally friendly practices in construction. The horsetail plant (Equisetum Hyemale) which is recognized for its abundant silica content, was incinerated at different temperatures to produce ash for investigation. The study included initial analysis by visually inspecting and weighing samples, then conducting ignition tests to measure carbon content and evaluate pozzolanic properties. Subsequently, Energy Dispersive X-Ray Analysis (EDX) and Scanning Electron Microscopy (SEM) were used to examine the elemental composition and morphology of the ash. Ignition tests showed that higher incineration temperatures are associated with lower carbon content and a rise in crystalline silica forms. Incinerating at 700 ℃ effectively decreased carbon content while maintaining the amorphous silica structure, making it the ideal temperature for bulk incineration. The study shows that horsetail ash, particularly when processed correctly, has great potential as an eco-friendly and economical additive for improving soil characteristics in geotechnical uses.

Evaluation of calcium carbonate production and cementitious characteristics of enzymatically induced carbonate precipitation during environmental adjustment

Enzymatically induced carbonate precipitation (EICP) is an emerging and eco-friendly technology, which is considered a green alternative to traditional cement in soil stabilization. When stabilizing soil use one-phase grouting method, the activity of urease is often adjusted, leads to changes in the composition and cementitious characteristics of CaCO3. Previous studies primarily focused on the mechanical properties of solidified soil samples, while the production and cementitious characteristics of CaCO3 influenced by the control of urease activity is rarely discussed. This study investigated production and cementitious characteristics of CaCO3 under different reaction environment (pH adjustment, temperature adjustment, and addition of inhibitors), during which the urease activity tests, pH tests, CaCO3 production tests and ultrasonic oscillation tests are conducted. Meanwhile, the morphological characteristics and mineral composition of CaCO3 are revealed through Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM-EDS) tests and X-ray Diffraction (XRD) test. The results demonstrate that all three one-phase grouting methods can delay the production of CaCO3 at early-stage of EICP, while the pH should be maintained above 4 to prevent significant urease deactivation. The CaCO3 generated in EICP mainly consists of calcite and vaterite, and the size of CaCO3 increases with the urease activity increased. The cementitious characteristics of CaCO3 is mainly determined by the percentage composition of calcite and vaterite, where higher vaterite content results in weaker cementitious characteristics. This study provides insights for evaluating the cementitious characteristics of CaCO3, which is beneficial for guiding the promotion and application of one-phase grouting method.

Organic matter stability in temperate forest soils is affected by tree species identity but not by litter quality

Organic matter stability in temperate forest soils is affected by tree species identity but not by litter quality

The Effects of Meander Reconnection and Deflector Installation on the Physicochemical Water Quality

ABSTRACTRiver restoration efforts are gaining momentum in response to the pressing need for resilient river systems, in light of escalating climate change impacts. However, achieving predefined restoration goals remains challenging due to insufficient understanding of river system responses. Of particular complexity is assessing the success of restoration measures on water quality, a critical abiotic factor in freshwater ecosystems. This study examined the impact of meander reconnection and deflector placement on water quality. Two distinct meander sections and a degraded section were meticulously sampled both upstream and downstream to assess impacts. The meander sections were reconnected using different approaches: one fully reconnected, receiving all discharge, and the other partially reconnected, receiving part of the discharge while maintaining the channelized trench. The results showed promising potential of reconnected meanders for mitigating phosphorus and carbon levels. However, the effectiveness of these improvements was compromised by deflector placement, which led to increased erosion and release of phosphorus bound to organic soil particles. Conversely, dissolved nutrients (e.g. nitrate, orthophosphate, DOC) exhibited no significant alterations, likely attributed to the absence of macrophytes and the limited extent of restorative actions, which currently do not increase water residence time sufficiently. Temporal trends revealed progressive reductions in carbon, phosphorus, and nitrogen levels suggesting that time is a crucial factor in restoration success, possibly due to soil stabilization. Seasonal dynamics also played a significant role, with discernible effects observed primarily during summer. This study underscores the importance of long‐term, watershed‐scale investigations that account for seasonal variability to fully understand the impacts of river restoration.

Field investigation of the feasibility of MICP for Mitigating Natural Rainfall-Induced erosion in gravelly clay slope

Rainfall-induced erosion on slopes is a prevalent natural process leading to soil loss. One promising application of microbially induced carbonate precipitation (MICP) is to mitigate rainfall-induced erosion. Conducting field tests is an essential step to verify and improve its performance. In the current work, field tests were conducted to assess the feasibility of using MICP to mitigate rainfall-induced erosion on a gravelly clay slope in Longyan, Fujian, China. A temporary laboratory was set up to cultivate bacteria, and a non-sterilizing method was employed to prepare large volumes of bacterial suspensions in a single batch. Slopes were treated by spraying solutions onto their surfaces. The amount of discharged soils and 3D surface scanning results were used for evaluating the erosion intensity of the slopes. The results demonstrated that the method could effectively mitigate the surface erosion caused by natural rainfall and prevent erosion-induced collapse. Notably, approximately one year after the treatment, the grass had started to grow on the heavily cemented slope, indicating that the MICP method is both effective and eco-friendly for soil stabilization method. However, further improvements are needed to enhance the uniformity and long-term durability of the MICP treatment.

Mechanisms of soil organic carbon and nitrogen stabilization in mineral-associated organic matter – insights from modeling in phase space

Abstract. Understanding the mechanisms of plant-derived carbon (C) and nitrogen (N) transformation and stabilization in soil is fundamental for predicting soil capacity to mitigate climate change and support other soil functions. The decomposition of plant residues and particulate organic matter (POM) contributes to the formation of mineral-associated (on average more stable) organic matter (MAOM) in soil. MAOM is formed from the binding of dissolved organic matter (ex vivo pathway) or microbial necromass and bioproducts (in vivo pathway) to minerals and metal colloids. Which of these two soil organic matter (SOM) stabilization pathways is more important and under which conditions remains an open question. To address this question, we propose a novel diagnostic model to describe C and N dynamics in MAOM as a function of the dynamics of residues and POM decomposition. Focusing on relations among soil compartments (i.e., modeling in phase space) rather than time trajectories allows isolating the fundamental processes underlying stabilization. Using this diagnostic model in combination with a database of 36 studies in which residue C and N were tracked into POM and MAOM, we found that MAOM is predominantly fueled by necromass produced by microbes decomposing residues and POM. The relevance of this in vivo pathway is higher in clayey soils but lower in C-rich soils and with N-poor added residues. Overall, our novel modeling in phase space proved to be a sound diagnostic tool for the mechanistic investigation of soil C dynamics and supported the current understanding of the critical role of both microbial transformation and mineral capacity for the stabilization of C in mineral soils.

Stabilization effect of nano-SiO2@iron-phosphorus on ferrallisols, calcareous soil and organic soil heavily polluted by heavy metals: A fast reaction curing stabilization process

The remediation of soil pollution by heavy metals (HMs) presents a significant challenge in environmental restoration. Stabilization remediation technology has proven effective in treating HMs contaminated soil. However, its development is constrained by drawbacks such as slow reaction kinetics and low adsorption capacity. This research synthesized a nano-SiO2@iron‑phosphorus (FPOH) material by SiO32− encapsulating the iron-phosphate precipitate obtained from Fe ion and phosphate. In addition, this research applied this material to ferrallisols, calcareous soils and organic soils with three different levels of high pollution by Cd, Pb, Cu and Zn. The experimental results indicate that all experimental soils stabilized rapidly within 1 day and met the requirements of remediation engineering standards (ChinaMEE HJ 1282-2023). Analysis of the possible mechanisms suggests that the FPOH material effectively fills voids with phosphate mineral formation, preventing the secondary release of HMs. During the stabilization process, FPOH involves the adsorption of free ions and small organic molecules in the soil, which does not affect its high reactivity. The development and utilization of FPOH offer valuable insights for soil stabilization remediation.

Stabilization of arsenic-cadmium co-contaminated soil with the iron-manganese sludge derived amendment: Effects and mechanisms

An iron-manganese sludge-derived amendment was proposed to remediate arsenic (As) and cadmium (Cd) co-contaminated soil, with a strong adsorptive capacity across pH 4 to 10. The Langmuir model defined maximum adsorption at 78.17 mg/g for As(III), 110.48 mg/kg for As(V), and 65.77 mg/g for Cd(II). The X-ray photoelectron spectroscopy (XPS) spectra provided insights into the chemical interactions: As was predominantly complexed or ligand exchanged with iron(hydr)oxides. In contrast, cadmium exhibited a tendency to bond with acylamino and carboxyl groups, in addition to the ferric hydroxyl groups. Notably, 42.15% of the adsorbed As(III) was oxidized into As(V) by Mn(IV) oxides present in the amendment. The soil-verification experiment demonstrated that an amendment dosage of 40 g/kg was efficacious in reducing the leaching concentration of As and Cd to maintained below the safety thresholds of 0.1 mg/L and 0.01 mg/L, respectively, for pH levels 4 to 11, meeting the Chinese Surface Water Quality Standard V (GB3838-2002). After the stabilization, the exchangeable fractions of As and the acid-soluble fractions of Cd were significantly reduced, with these elements being transformed into more stable forms. The amendment maintained the soil's neutral pH and adjusted the soil physicochemical properties. This article presents a holistic approach by examining the organic-inorganic composite of iron-manganese oxides with polyacrylamide, modified as a stabilizing amendment for As and Cd co-contaminated soil. This innovative amendment adeptly navigates the previously conflicting stabilization mechanisms for anionic and cationic metals. Offering dual advantages, the amendment not only remediates soil but also addresses the disposal of waste, presenting a win-win solution for environmental management.

Stabilization and Remediation of Arsenic-Contaminated Soil: Fly Ash-Based Technology for Industrial Site Restoration

Arsenic contamination of various environmental components poses a serious threat to human and animal health. Soil As contamination is particularly hazardous, as soil is a vital pathway to the food chain. We conducted experiments on soil from a typical pharmaceutical and chemical industry relocation site in Hubei Province, focusing on modification using fly ash through mechanical and chemical mechanisms. We subjected varying proportions of lime, ferrous sulfate, and fly ash to mechanical ball milling and used these mixtures to perform remediation of arsenic-contaminated soil and site restoration. Our findings are as follows: in soil culture experiments, the As stabilization efficiency reached 90% within 90 days with ferrous salt-modified fly ash. In actual site restoration, As-stabilization efficiency exceeded 95% across different soil depths within 30 days, demonstrating significant stabilization effects. Optimal modified dosages were determined as 2% ferrous sulfate and 2% fly ash. After stabilization, As in the soil primarily existed in amorphous iron-aluminum oxide-bound (F3) and crystalline iron-aluminum oxide-bound (F3 + F4) and residual (F5) states. Fluctuations in the moisture content and pH mainly activated F3 and F4, transitioning them into exchangeable (F1) and surface-adsorbed (F2) states. Arsenic leaching was predominantly associated with the F1 form. Fly ash-based restoration technology demonstrates promising capabilities in waste treatment and pollution control, offering significant potential for widespread application.

Research advance in the effects of litter input on forest soil organic carbon transformation and stability.

The turnover and stabilization of soil organic carbon are tightly associated with the properties of litter input. Due to the complexity of litter decomposition and the high heterogeneity of forest soils, there are considerable uncertainties about how soil minerals, microorganisms, and environmental factors jointly regulate the transformation and stability of litter-derived soil organic carbon. Here, we present an overview of the "microbial efficiency-matrix stabilization" framework centered on microbial metabolism and organic carbon transformation, as well as the new "microbial carbon pump" and "mineral carbon pump" theories in forest soil organic carbon transformation and stabilization. We specifically highlighted a differential mechanism of "organo-organic interfaces" from the "organo-mineral interfaces" in the effects on soil organic carbon accumulation. We further expounded the transformation processes and stability of soil organic carbon based on the "carbon material cycling" and "energy fluxes", aiming to provide theoretical support for the research on carbon sequestration in forest soils.