A nonlinear creep model of hard structural planes.

Hard structural planes mainly exist in rock slopes and their creep characteristics largely determine slope stability. Traditional models have some shortcomings in describing the creep characteristics of hard structural planes, such as poor adaptability and unclear physical meaning of parameters. In order to overcome these shortcomings, based on the creep failure mechanism of hard structural planes, an element combination model is adopted in the study.

Source tracing analysis of the exceedance of NH-N and COD in shallow groundwater in the central typical area of the Yangtze river delta.

With the accelerated urbanization process in the Yangtze River Delta region, shallow groundwater has received increasing attention. In this work, the exceedances of the ammonium nitrogen (NH-N) and chemical oxygen demand (COD) in shallow groundwater in the central typical area of the Yangtze River Delta were investigated. With the utilization of the national monitoring well (QY10A) as a focal point, a combination of methods, including onsite sampling, hydrogeological surveys, leaching tests, water quality analysis, and isotope tracing, was employed to comprehensively examine groundwater pollution.

Effects of mixing water and environmental pH value on the properties of sulfoaluminate cement-based ultra-high water materials.

In order to grasp the influence of the pH value of mixing water and environmental water on the properties of ultra-high water materials, this article separately carried out the influence of different pH values of mixing water on the properties of ultra-high water materials and the conservation of high-water materials in water environments with different pH values. Using test methods such as loss of flow time, compressive strength, Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Thermogravimetric-Differential Thermal Analysis (TG-DTA), to conduct regular exploration and mechanism analysis. The study found that with the continuous increase of the pH value of the mixing water, the loss of flow time of the ultra-high water material gradually decreased, and the compressive strength of the samples at the same age continued to increase.

Rock crack initiation triggered by energy digestion.

The critical value of rock failure is determined by irreversible deformation (inelastic deformation, damage, and other internal dissipation) processes and external conditions before rock failure. Nevertheless, a thorough explanation of the mechanism causing cracks in rock material has not yet been provided. The strain energy theory is applied in this work to assess the initiation of rock cracks and investigate the relationship between energy digestion and rock strength.

Spalling Criterion of Hard Brittle Rock Mass Based on Dilatation Lateral Strain.

Spalling failure is a typical failure phenomenon after excavation and unloading of a deep, hard brittle rock mass, which seriously threatens the safe construction of deep roadways (tunnels) and other projects. From the engineering viewpoint, it is essential to accurately evaluate the range and depth of surrounding rock spalling failure. From the perspective of the laboratory and engineering site, the strength and formation mechanism of hard rock spalling failure were statistically summarized and analyzed.

Adsorption Potential, Speciation Transformation, and Risk Assessment of Hg-, Cd-, and Pb-Contaminated Soils Using Biochar in Combination with Potassium Dihydrogen Phosphate.

The objective of this study is to develop a remediation technology for composited heavy metal-contaminated soil. Biochars (BC300, BC400, and BC500) derived from corn were combined with potassium dihydrogen phosphate (KHPO) to immobilize and remove heavy metal ions, including mercury (Hg), cadmium (Cd), and lead (Pb). The adsorption kinetics of metal ions in aqueous solutions with different concentrations was tested, and the fitting effects of the two models were compared.

Study on the compounding optimization of surfactants and synergistic effects on the wettability of bituminous coal.

To improve the wettability of surfactants on bituminous coal and to explore its wettability and wettability mechanism on bituminous coal, taking the Sandaogou bituminous coal as an example, a single factor experiment was carried out first. Through contact angle and surface tension experiments, three surfactants with good wettability were selected from among the nine surfactants and mixed in equal proportions two by two to determine the optimal compounding method and compounding concentration. The experimental results show that the compounding of nonionic and anionic, nonionic and zwitterionic, anionic and zwitterionic surfactants can have synergistic effects and significantly improve the wettability of bituminous coal.

Research on prediction of in open-pit mine used RUN-XGBoost model.

The drill-blasting method is a commonly used mining technique in open-pit mines, and the peak particle velocity () caused by blasting vibrations is an important indicator for evaluating the rationality of blasting mining design parameters. To develop an effective prediction model, a parameter self-optimizing RUN-XGBoost prediction model is implemented using the Runge-Kutta optimization algorithm (RUN) combined with extreme gradient boosting (XGBoost). The factors affecting the prediction of , including maximum explosive (), total explosive (), blast center distance (), blast hole depth (), and height difference between the measurement location and the blast location (), are selected as the influencing indicators.

Reaction Process of Solid Waste Composite-Based Cementitious Materials for Immobilizing and Characterizing Heavy Metals in Lead and Zinc Tailings: Based on XRD, SEM-EDS and Compressive Strength Characterization.

This study investigates the synergistic effect and mechanism of gelling materials with blast furnace slag (BFS), steel slag (SS) and desulphurization gypsum (DG) as the main components on the hardening of heavy metal ions by lead and zinc tailings. It is found that lead and zinc tailing (LZT) is mainly composed of dolomite and quartz and contain small amounts of calcium, aluminum, iron, magnesium and other elements as well as heavy metals such as lead and zinc. By the mechanical activation method, it is found that the lead and zinc tailings powder has the largest specific surface area and the highest activity index when the ball milling time is 2 h.

Study on the influence of pore water pressure on shear mechanical properties and fracture surface morphology of sandstone.

To further investigate the weakening effect of pore water pressure on intact rock mechanics properties and characteristics of fracture surface after failure, direct shear tests of sandstone were conducted under different pore pressure. A 3D scanner was employed to digitize the morphology of the post-shear fracture surface. The variogram function was applied to quantify the anisotropic characteristics of post-shear fracture surface.

Controlling toxic and harmful gas in blasting with an inhibitor.

In engineering blasting, while efficiently breaking rocks with explosives, a large amount of toxic and harmful gases are generated, which not only pollutes the production environment but also easily leads to explosion smoke poisoning accidents. It must be highly valued by engineering technicians and management personnel. To effectively control the production of harmful gases during explosive blasting, an environmentally friendly and efficient harmful gas inhibitor has been developed, and its mechanism of action has been analyzed and revealed.

Measurement and influencing factors of carbon emission efficiency based on the dual perspectives of water pollution and carbon neutrality.

The achievement of the 'Carbon Dioxide Removal' vision has become a crucial strategic objective for national development. However, the carbon emissions produced during wastewater treatment processes hinder the attainment of the 'Carbon Dioxide Removal' targets. Addressing water pollution is not only essential for achieving the goal of 'carbon dioxide removal' but also for enhancing the carbon emission efficiency (CEE).

Fluorides immobilization through calcium aluminate cement-based backfill: Accessing the detailed leaching characterization under torrential rainfall.

Urbanization and economic development have increased the demand for fertilizers to sustain food crop yields. Huge amounts of by-products, especially phosphogypsum (PG), are generated during the wet processing of rock phosphate to produce fertilizers. Chronic exposure to fluoride in phosphogypsum in groundwater as a result of the weathering of fluoride-containing waste poses a significant health risk to millions of people.

Study on the proportion of paste filling materials based on fluorogypsum.

A new type of paste filling material was created using fluorogypsum, a byproduct of hydrofluoric acid, as the raw material to address the issue of the filling material's high cost. The effects of five factors, including gangue, fly ash, fluorogypsum, lime content, and mass concentration on the physical and mechanical properties of filling material were also examined. In addition to analyzing slump and extension changes, the filler's mineral composition and microstructure were examined using SEM and XRD examinations.

Experimental study on ratio optimization and application of improved bonded dust suppressant based on wetting effect.

Traditional bonded dust suppressants have high viscosity, insufficient fluidity and poor permeability problems, which is adverse to the formation of a continuous and stable solidified layer of dust suppressant solution on the surface of a dust pile. Gemini surfactant has efficient wetting performance and environmental protection performance, it is introduced as a wetting component to improve the flow and penetration performance of bonded dust suppressant solution, polymer absorbent resin (SAP) and sodium carboxymethyl starch (CMS) were selected as the main components of dust suppressant. A proportioning optimization model was constructed based on response surface methodology (RSM), and the concentration of each dust suppression component was selected as the independent variable, water loss rate, moisture retention rate, wind erosion rate and solution viscosity were chosen as the dependent variables in this model.

Characterization of the Physical Chemistry Properties of Iron-Tailing-Based Ceramsite.

In order to deal with the problems of resource waste and environmental pollution caused by solid waste, iron tailings (mainly SiO, AlO and FeO) were used as the main raw material to create a type of lightweight and high-strength ceramsite. Iron tailings, dolomite (industrial grade, purity 98%) and a small amount of clay were combined in a N atmosphere at 1150 °C. X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and a themogravimetric analysis (TGA) were performed and the specific surface area was analyzed to determine the strength and adsorption of the ceramsite.

Heat Hazard Control in High-Temperature Tunnels: Experimental Study of Coupled Cooling with Ventilation and Partial Insulation for Synergistic Geothermal Extraction.

The problem of heat hazard in tunnel engineering has seriously affected the normal work of personnel and machinery. After combining the heat hazard control method of controlling the energy source and blocking the energy transfer, a technical scheme of precise thermal insulation at the working face in concert with geothermal energy extraction is proposed, forming a coupled cooling method of ventilation and partial thermal insulation. By building a scaled model test platform, the temperature field of the working area was analyzed, and the effect of factors, such as with or without a thermal insulation layer, ventilation velocity, and surrounding rock temperature on the cooling limit, was discussed.

Mechanical properties and acoustic emission characteristics of deep hard coal after segmented high-temperature treatment.

Based on engineering background that local heating of coal seam is uneven due to underground coal gasification, coal-bed gas exploitation via heat injection, spontaneous combustion of coal seam, etc., segmented heating coal sample was used to simulate coal seam under uneven heating condition, and experimental study on mechanical behaviors of coal sample after segmented heat treatment at high temperatures was conducted. Test results show that temperature at 100 °C ~ 400 °C did not reach ignition temperature of deep hard coal for the experiment and was not enough to change main ingredients of coal sample, which less affected compression strength, elastic modulus, acoustic emission behavior of coal sample.

Mechanical Properties and Failure Behavior of Dry and Water-Saturated Foliated Phyllite under Uniaxial Compression.

Phyllite is widely distributed in nature, and it deserves to be studied considering rock engineering applications. In this study, uniaxial compression tests were conducted on foliated phyllite with different foliation angles under dry and water-saturated conditions. The impacts of water content and foliation angle on the stress-strain curves and basic mechanical properties of the Phyllite were analyzed.

In-situ remediation of phosphogypsum in a cement-free pathway: Utilization of ground granulated blast furnace slag and NaOH pretreatment.

In-situ remediating phosphogypsum (PG) for cemented paste backfill (CPB) in the contaminated site is economic management for promoting sustainable developments in the phosphate industry. This study concerns the combined use of NaOH pretreatment and ground-granulated blast furnace slag (GGBFS) additives to promote the solidification/stabilization of PG with a lower carbon footprint pathway. According to physico-chemical analyses, the NaOH pretreatment effectively removed approximately 95% of F within the PG, which may originally be present as sparingly soluble fluorides or coexisting with silicates.

The Phosphorus Transport in Groundwater from Phosphogypsum-Based Cemented Paste Backfill in a Phosphate Mine: A Numerical Study.

Stacked phosphogypsum (PG) can not only cause a waste of resources but also has a serious negative impact on the surface environment. Phosphogypsum backfilling (PGB) in the underground goaf is a useful approach to effectively address the PG environmental problems. However, the effects of this approach on the groundwater environment have not been studied.

Leaching of heavy metal(loid)s from historical Pb-Zn mining tailing in abandoned tailing deposit: Up-flow column and batch tests.

This study aims to investigate the water-leaching characteristics of heavy metal(loid)s (HMs) from historical Pb-Zn mine tailing of an abandoned tailing deposit in eastern China. Up-flow column and batch leaching tests were conducted at different liquid-to-solid (L/S) ratios to estimate the releases of HMs and investigate the controlling mechanisms. Calcite and silicate were the dominant minerals in the tailing and the HMs contents followed the order of Zn (2371 mg/kg) > Pb (2061 mg/kg) > Cu (109 mg/kg) > Cr (47.

Sulfur vacancies on MoS enhanced the activation of peroxymonosulfate through the co-existence of radical and non-radical pathways to degrade organic pollutants in wastewater.

The enhancement of vacancies in catalysts involving Fenton-like reactions is a promising way to remove organic pollutants in wastewater, but sulfur vacancies are rarely involved. In this work, MoS containing defect sites were synthesized by a simple high-temperature treatment and then applied for activating peroxymonosulfate to eliminate organic pollutants in wastewater. The structure was characterized by several techniques such as XRD, BET, and XPS.

Highly-efficient fluoride retention in on-site solidification/stabilization of phosphogypsum: Cemented paste backfill synergizes with poly-aluminum chloride activation.

Phosphogypsum (PG) is a massively generated hazardous by-product in the phosphorus industry. Large-scale, efficient, profitable on-site recycling is an emerging topic for promoting sustainable phosphorus circularity and mitigating potential human exposure. In this work, we integrated a green and low-cost additive polymeric aluminum chloride (PAC) into the binder design of PG immobilization.