Increase In Moisture Content Research Articles

Characteristics of the gas diffusion in water-bearing coal with different damage degree and its influence mechanism

The moisture content and degree of damage in water-bearing coal affect the gas diffusion characteristics in coal, which limits the effect of gas extraction. The experiments were carried out on water-bearing coal with different damage degrees using a self-built coal and gas adsorption–desorption system to study the gas diffusion characteristics of water-bearing coal with varying degrees of damage. The results show that the pore volume of tectonic coal is positively correlated with the degree of damage. The increased moisture content in coal decreases gas desorption performance, embodied in the simultaneous reduction of desorption amount, desorption speed, and diffusion coefficient. Under the same water content condition, the gas desorption amount, gas desorption rate, and gas diffusion coefficient of coal with different damage degrees all show a downward trend, and the decline range is positively correlated with the water content. The relation between the amount of gas desorption, the time, and the moisture content of the water-bearing coal with different damage degrees has been set up. The study results provide a solid theoretical foundation for evaluating and predicting the gas extraction characteristics of coal seams with varying degrees of damage.

Impact of Date-Palm Fibers on Fine Soil’s Compaction and Strength Properties

This paper investigates the influence of date-palm fibers on the compaction and strength properties of fine soil. The laboratory tests, including specific gravity, compaction tests, and unconfined compression strength tests, were conducted, integrating different proportions (ranging from 0 to 2%) of date-palm fibers into the soil mixture. The palm fibers were divided into two distinct lengths (30 mm and 60 mm) to be mixed with the soil. Nine samples were prepared with varying proportions of date-palm fibers for the experimental investigation, aiming to specifically examine the influences exerted by both palm-fiber length and palm-fiber content on the soil's compaction and strength characteristics when mixed with date-palm fibers. The compaction test results demonstrate a decrease in the dry unit weight and an increase in the optimum moisture content by approximately 10%. Additionally, the length of the date-palm fibers impacts the optimum moisture content and the maximum dry unit weight of the soil mixture. In contrast, the unconfined compressive stress increased by about 30% with higher date-palm fiber contents. This increase in unconfined compressive stress due to increased date-palm fiber content is a significant finding, indicating improved soil strength. This finding holds the enhancing construction performance, sustainability, and cost-efficiency. In conclusion, this soil-fiber mixture shows suitable hydraulic applications. The utilization of natural materials in civil engineering demands the exploration of available natural fibers.

Alterations in the fillet quality of myostatin-knockout red sea bream Pagrus major: Preliminary insights into nutritional, compositional, and textural properties

Myostatin (MSTN) is a negative regulator of skeletal muscle growth and a popular target for enhancing the productivity of farmed fish. We previously developed an mstn-knockout breed of the aquaculture fish red sea bream (Pagrus major) using genome editing technology. However, little is known about the effects of mstn disruption on the fillet quality of red sea bream and other fish species. In this study, we used fillets of mstn-deficient red sea bream to evaluate their compositional and textural changes during refrigeration. Compared to the wild type, the mutant fillets exhibited an increase in moisture content and a decrease in drippings, indicating an enhanced water-holding capacity. Furthermore, the mutant fillets showed increased water retention and marginally lower collagen content, resulting in lower breaking force, an index of texture. In conclusion, we demonstrated that mstn disruption alters the compositional and textural properties of red sea bream fillets.

Evaluation of Deterioration Degree of Archaeological Wood from Luoyang Canal No. 1 Ancient Ship

This study provides a detailed investigation of archaeological wood samples from the Luoyang Canal No. 1 site, focusing on wood species identification, physical properties, mechanical property analyses, and morphological examination. The identified wood species, belonging to the Ulmus genus, exhibited a 43% decline in compressive strength in waterlogged environments. Further, the wood exhibited increased moisture content, higher porosity, reduced basic density, and elevated shrinkage rates, indicating a mild level of degradation. X-ray diffraction was employed for the observation of cellulose structure, and Fourier transform infrared spectroscopy (FT-IR) demonstrated significant removal of cellulose and hemicellulose components. These findings emphasize the importance of understanding wood degradation mechanisms to evaluate structural integrity and durability in guiding the development of effective preservation strategies for archaeological wood artifacts. Continued research and conservation are crucial to deepen our knowledge of wood deterioration processes and enhance the implementation of preservation techniques.

Influence of moisture on the sound absorption properties of wood-based pulp fibre foams

The use of wood fibres, and other biofibres in general, as raw materials to produce sound absorbers has gradually increased lately. The main reason for their increased use is their contribution to reducing CO2 from the atmosphere by binding CO2 into the building structure for decades. Understanding of the ultrastructure of wood fibres is essential as it has a strong influence on the fibre properties, and thus, on the final material properties. In this work, the effect of moisture on the sound absorption properties of wood-based pulp fibre foams has been studied. It is shown that increasing moisture content (> 9%) in pulp fibres leads to greater sound absorption at low-mid frequencies. Fibre swelling, increasing fibre flexibility, and increasing foam bulk density with increasing fibre moisture content are hypothesized as the causes for the increase in sound absorption. Hygroexpansion, mechanical properties as well as moisture absorption capability of different types of pulp fibres are studied and related to their sound absorption properties. It is concluded that, in addition to fibre diameter and bulk density of foams, the elastic properties of the pulp fibres are partially responsible for the improved sound absorption of the foams exposed to greater relative humidity conditions.

Experimental investigation of influence of amide polymer on loess for subgrade

The effects of moisture and drying shrinkage can lead to uneven settlement, cracking, and other diseases in loess subgrade. The objective of this study was to investigate the effects of amide polymer (AP) on the permeability, mechanical properties and crack resistance of loess by orthogonal experiments. The basic properties of AP and the permeability, mechanical properties, and dry–wet variation properties of polymer-modified loess were tested, and a scale model verification and simulation analysis were conducted. In this paper, water migration in subgrade is regulated by improving the water sensitivity of loess. By reducing the variation range of subgrade water content, the stress accumulation in subgrade caused by water is weakened. The results show that the curing time and mechanical properties of AP are directly affected by the oxidant and reducing agent, and the mechanical properties of AP are compatible with the characteristics of loess. AP filled the grain gap and reduced the permeability of loess by 34.05–280.83%. The ductility of polymer-modified loess is significantly increased, and the strain of peak strength is increased by 17.21–126.36%. AP can regulate moisture change, reduce the surface tension between particles, and reduce stress concentration. The strength loss rate was reduced by 19.98–51.21% by enhancing the cracking resistance and weakening the strength loss caused by dry and wet cycling. The increase of upper layer moisture content in the scale model of polymer-modified loess subgrade is reduced by 31.38–36.11%.

Effects of vegetation extreme degradation on soil hydrothermal processes in alpine wet meadow on the central Qinghai–Tibet Plateau

Ongoing climate warming and humidification have triggered a series of environmental responses, including vegetation succession, significant permafrost degradation, hydrological shifts, alterations in water resources, and increased frequency of freeze-thaw events. Notably, vegetation modulates the water cycle, regulates soil temperatures, and sustains permafrost stability. However, the extent to which the degradation of alpine vegetation impacts soil hydrothermal processes in permafrost regions is unclear. Therefore, we measured the soil moisture and temperature of the alpine wet meadow (AWM) and extremely degraded alpine wet meadow (EDAWM) ecosystems within the permafrost regions of the Qinghai–Tibet Plateau in situ. The objectives of this study were to explore the freeze-thaw cycles and hydrothermal dynamics within the active layer and to understand the mechanisms behind the effects of extreme alpine vegetation degradation. The results revealed that the AWM ecosystem had a longer soil freezing duration and a higher soil freezing rate than those of the EDAWM ecosystem. Additionally, the freezing index was higher in EDAWM than that in AWM, while differences in the thawing index were insignificant. The variance in the thaw-freeze ratios between the two ecosystems indicated that extreme vegetation degradation in AWM altered soil heat absorption and dissipation in the plant root zone and the deeper active layer. Moreover, EDAWM exhibited a decrease in soil bidirectional freezing processes, particularly from the permafrost table upwards. The extreme degradation in AWM changed soil physical properties and organic matter content, reducing ground temperatures in the active and permafrost layers of EDAWM, particularly during winter. The reduced heat transfer in EDAWM resulted in an active layer depth 9 cm shallower than that in AWM. Without vegetation cover, soil moisture in EDAWM was more prone to evaporation or deeper infiltration, leading to lower soil moisture content than that in AWM. Furthermore, an increase in soil moisture content decreased temperature in shallow soils in AWM but increased it in shallow soils in EDAWM. In summary, extreme vegetation degradation impaired air-heat exchange in AWM soil. These insights provide a scientific and theoretical basis for predicting permafrost evolution in the Qinghai–Tibet Plateau, highlighting the complex interactions among vegetation degradation, soil hydrothermal processes, and climatic factors.

Dynamic mechanical response and failure characteristics of coal and rock under saltwater immersion conditions

The stability of coal and rock masses in water-rich mines is affected by both mine water erosion and dynamic disturbances. Thus, it is necessary to study the dynamic mechanical response and failure characteristics of coal and rock under the combination of saltwater and a high strain rate. To this end, a split Hopkinson pressure bar device was employed to investigate the effects of impact velocity, water content, and immersion liquid on the dynamic mechanical behaviours of coal and rock. The results revealed that the weakening effect of saltwater on the dynamic mechanical properties of coal and rock is much greater than that of distilled water. With increasing moisture content, the dynamic compressive strength of the coal specimens decreases monotonically, while that of the rock shows a trend of first increasing and then decreasing. The failure process and destruction of coal and rock are comprehensively affected by both the external impact load and the physical and mechanical properties of the material. The degree of damage of the coal and rock specimens increases with increasing impact velocity and water content. Moreover, the influence of various factors on the impact fracture mechanism of coal and rock under saltwater immersion conditions was revealed. These findings are highly important for the design and maintenance of underground coal and rock building structures.

Exploring Chitosan Lactate as a Multifunctional Additive: Enhancing Quality and Extending Shelf Life of Whole Wheat Bread.

The shelf life of whole wheat bread (WWB) significantly impacts its freshness and overall quality. This research investigated the impact of chitosan lactate (CL) on various characteristics influencing the shelf life of WWB, including its physical, chemical, textural, antimicrobial, and sensory attributes. These characteristics were evaluated by conducting various experiments such as physical inspection, moisture, impedance, swelling, color, texture, FTIR, microbiological, and sensory analysis. CL with different concentrations was incorporated into WWB formulations: P0.0 (0.0% w/w CL, control), P0.5 (0.5% w/w CL), P1.0 (1.0% w/w CL), P2.0 (2.0% w/w CL), and P3.0 (3.0% w/w CL). The inclusion of CL promoted the Maillard reaction (MR) compared to P0.0. The promotion of MR resulted in the formation of a shinier crust, which increased as the CL content was increased. P0.5 comprised large-sized pores and exhibited increased loaf height. CL-containing WWB formulations showed an increased moisture content and decreased impedance values compared to the control. FTIR analysis of P0.5 demonstrated the enhanced interaction and bonding of water molecules. P0.5 demonstrated optimal textural, colorimetric, and antimicrobial properties compared to other formulations. The sensory attributes of WWBs remain unchanged despite CL addition. In conclusion, P0.5 exhibited optimal characteristics associated with better quality and prolonged shelf life.

Self-heating and spontaneous ignition of biomass storage piles: Towards a reliable prediction tool

Large-scale biomass storage for modern bioenergy introduces potential safety concerns due to the intrinsic self-heating of biomass. Despite this, very limited research has been conducted in this area. This project fills a critical gap by developing a comprehensive modelling framework for self-heating in biomass piles and conducting a series of experimental studies to explore the intricate sub-processes within these piles. This paper presents only a small portion of the modelling and testing work. It successfully demonstrates the model's usefulness in predicting self-heating in coal piles, guiding safety measures for coal storage. Among various storage parameters, the pile height, particle size and ambient wind velocity have been identified as having substantial impacts on self-heating and self-ignition within the coal pile. This paper also illustrates the pronounced effects of initial biomass moisture content on microbial reactivity and oxygen consumption rate. An increase in initial moisture content significantly enhances the overall microbial reactivity and oxygen consumption rate. Wheat straw, compared to rice straw, is more prone to self-heating under identical storage conditions, as evidenced by higher heat generation, faster oxygen consumption, and a shorter time to peak temperature. Moreover, microbial activity is found to play a critical role in biomass self-heating, particularly in the temperature range of 0–75 °C, during the initial stages of heat accumulation. For the modelling discussed here, the flow within the porous pile must be considered laminar, despite the highly turbulent flow around the pile. This is based on the Reynolds number, calculated from the in-pile volume average of the velocity and the mean diameter of the fuel particles, which is significantly below the critical threshold (Recr=200). The insights and sub-models to be derived from the relevant sub-processes in biomass pile can be integrated into the model framework. This integration will create a more comprehensive and robust model for predicting self-heating and self-ignition in biomass storage piles, enhancing both theoretical and practical management of these phenomena.

Characterisation of wholegrain composite for pretzels: a comprehensive nutritional and functional analysis

SummaryWholegrain composite flours are used for bakery products to enhance their nutritional value and to decrease the reliance on wheat importation as well as to ensure food security in most developing countries. This work aimed to optimise oat, maize, barley and wheat flour levels in the development of nutritionally enriched wholegrain pretzels. Composite flour blends were prepared by mechanical mixing of oat flour (OF), barley flour (BF), maize flour (MF) and wheat flour (WF) in the following proportion: WF (100%) (T0 – control), W:B (90:10) (T1), W:M (90:10) (T2), W:O (90:10) (T3), W:B:M:O (85:5:5:5) (T4), W:B:M:O (76:8:8:8) (T5) and W:B:M:O (70:10:10:10) (T6). Wholegrain composite flour mixes were analysed for their proximate composition and antioxidant properties. The fat, protein, ash and moisture content significantly changed (P < 0.05) in all treatments, while the fibre content increased. DPPH radical scavenging activity and total phenolic and flavonoid content showed significant changes compared to the control. A rapid visco analyser determined multigrain flour's rheological and pasting properties, and the values showed significant (P < 0.05) differences for peak viscosity, final viscosity and pasting temperature. The final product was analysed for proximate analysis, texture, colour and sensory evaluation. The increase in moisture, protein, fibre and ash content of the product was observed. Moisture, fat and fibre content of pretzels exhibited significant correlations (P < 0.05) with the sensory parameters. A grouping of the samples in function of the chemical and sensory characteristics was depicted from the principal component analysis. Texture and colour analysis showed significant differences (P < 0.05). Sensory evaluation results showed that the overall score for acceptability found for composite flour mix which contains 10% barley, 10% oat and 10% maize with wheat in a 30:70 ratio was accepted by the consumer. Consumption of wholegrain pretzels as snack food can contribute to a nutritious and balanced diet.

Strategi Perbaikan Kualitas Biosolar Berdasarkan Kandungan Air dan TAN yang Meningkat Akibat Penyimpanan di Ruang Terbuka

This study conducted a trial of B-30 products stored in miniature storage tanks outdoors to produce B-30 offspec products. Tests were also carried out on offspec B-30 products blended with new biosolar products. The research focused on the analysis of water content and Total Acid Number (TAN) using tools and materials that have been determined. The test results showed that biosolar products stored for two weeks in open space had an increase in moisture content and TAN value. An increase in water content is due to condensation during prolonged storage, while an increase in the TAN value indicates damage to the product. The addition of new biosolar in biosolar offspec aims to improve the quality of BioSolar damaged by storage. This study is relevant to understand the impact of storage on biosolar quality and improvement strategies that can be done.

Predicting the changing insect threat in the UK heritage environment

Environmental changes affecting museums and historic properties will probably result in increased numbers of insect pests or new species. Databases such as WhatsEatingYourCollection (WEYC) and the Global Biodiversity Information Facility have been used along with academic publications to predict such changes in the research presented here. The species mix in the WEYC database seems consistent across major London historic properties. Overall, common silverfish (Lepisma saccharinum) are often reported, although in future there may be an increase in other species such as Ctenolepisma longicaudatum and Ctenolepisma calvum given their increased frequency. Dermestidae (carpet and furniture beetles) may benefit from wood with increasing moisture content, and although not especially abundant, Attagenus smirnovi (brown carpet beetle) and Reesa vespulae (skin beetle) may increase as they have done on the European continent. Tineola bisselliella, a damaging moth, has invoked increasing concern over the last two decades and Cryptophagus spp. (fungus beetles) could mobilise fungal spores under a future climate more favourable to germination. Lyctus brunneus (powderpost beetle) may find future conditions favourable and attack sapwoods used in repairs. Furthermore, Reticulitermes flavipes (subterranean termite) is potentially an accidental import to the UK and may become more common given current temperatures are suitable for survival in well-drained loamy soils, and future climates would allow a presence in the north of England. Warmer conditions can lead to the presence of new species or a migration of species across the British Isles and their spread can also be encouraged through the loan of objects or on packing materials. Factors other than climate, such as changing indoor habitats, new food sources and novel uses of heritage venues can also encourage expanding insect populations. This article summarises these predicted changes in species distribution and outlines their potential threat to heritage.

Characterization of Red Cabbage Extracts incorporated in Green Based Gelatin Active Films

This study aimed to assess red cabbage extracts obtained using solvents with different pH levels and alcohol concentrations, comparing their phytochemical quantities and functional characteristics. Solvents—purified water (PW, pH 7), 70% and 99% ethanol (70%E and 99%E, pH 6.5), and acidified ethanol (AE, pH 2)—were employed for extraction. When the different pH solutions were applied to the red cabbage extracts, they altered the extract's color, ranging from pink to yellow, influenced by various anthocyanin forms responsive to pH levels. The AE-extracted red cabbage displayed the highest UV and visible light barrier and total phenolic content (TPC). Then, the AE extract was used to formulate the green-based gelatin active films, alongside the 99%E extract, which had similar alcohol content and TPC values. The films averaged 20-21 μm in thickness. Moreover, incorporating both extracts into the gelatin films increased moisture content and water solubility, though the change in water vapor permeability was not significant compared to the neat gelatin film. The gelatin film incorporating AE-extracted red cabbage (GAE) showed higher water solubility than that incorporating the 99%E extract (GE). Both green-based gelatin active films showed differences in appearance color in the third week. The GAE film exhibited greater color stability, attributed to anthocyanin's distinctive chemical structures favoring acidic environments. This gelatin film incorporating red cabbage by AE-extracted holds promise as an eco-friendly active food packaging material.

Effect of Planting Media and Cultivation Method in the Offshoots Growth of Date Palm Phoenix Dactylifera L. Hillawi cv.

Objective: The study aimed to explore the effects of different planting medium on the growth of date palm Hillawi cv. offshoots. Methods: The experiment included two main factors: the first factor was planting media, consisting of three treatments: field soil, zeolite + field soil (in a 2:1 ratio), and zeolite + sand (in a 2:1 ratio). The second factor was cultivation method, comprising three methods: traditional planting, container planting (using pots), and planting in lined holes with a layer of agricultural polyethylene (nylon). Results: Planting medium significantly influenced the growth of the offshoots. Specifically, planting media with zeolite and sand exhibited significant improvements in leaf length, dry matter content, leaf area, root count, root length, and diameter compared to the control group. Conversely, the zeolite-field soil combination exhibited a marked increase in moisture content. Additionally, electrical conductivity (EC) within the planting media was notably higher in the control condition featuring only field soil. The study also found that the chosen cultivation method significantly influenced the growth of the offshoots. The lined holes method displayed significant advantages in leaf length, dry matter content, leaf area, root count, root length, root diameter, and moisture content within the planting media, compared to the traditional approach. Conversely, the traditional method resulted in higher EC within the planting media. Conclusions: The study reveals significant effects of cultivation medium, method, and their interaction on various growth parameters of date palm offshoots. This study recommends the lined-hole planting method and zeolite-infused medium for enhanced offshoot growth.

Impact of Vetiver Plantation on Unsaturated Soil Behavior and Stability of Highway Slope

Due to cyclic wetting and drying, the hydro-mechanical behavior of unsaturated soil is impacted significantly. In order to assess the soil strength parameters, knowing the unsaturated behavior is important. Soil moisture content is an important parameter that can define the shear strength of the soil. Most of the highway slopes of Mississippi are built on highly expansive clay. During summer, the evaporation of moisture in the soil leads to shrinkage and the formation of desiccation cracks, while during rainfall, the soil swells due to the infiltration of water. In addition to this, the rainwater gets trapped in these cracks and creates perched conditions, leading to the increased moisture content and reduced shear strength of slope soil. The increased precipitation due to climate change is causing failure conditions on many highway slopes of Mississippi. Vetiver, a perennial grass, can be a transformative solution to reduce the highway slope failure challenges of highly plastic clay. The grass has deep and fibrous roots, which provide additional shear strength to the soil. The root can uptake a significant amount of water from the soil, keeping the moisture balance of the slope. The objective of the current study is to assess the changes in moisture contents of a highway slope in Mississippi after the Vetiver plantation. Monitoring equipment, such as rain gauges and moisture sensors, were installed to monitor the rainfall of the area and the moisture content of the soil. The data showed that the moisture content conditions were improved with the aging of the grass. The light detection and ranging (LiDAR) analysis was performed to validate the field data obtained from different sensors, and it was found that there was no significant slope movement after the Vetiver plantation. The study proves the performance of the Vetiver grass in improving the unsaturated soil behavior and stability of highway slopes built on highly expansive clay.

The effects of sugar substitution with cinnamon powder in moringa jelly candy

This study aimed to evaluate the effects of sugar substitution with cinnamon powder (CP) on moringa jelly candy (MJC). Four MJC formulations were made based on the level of sugar substitution using 0%, 7.5%, 15%, and 22.5% CP, coded as control, F1, F2, and F3, respectively. Samples were then analyzed for nutritional content, water activity, color, texture, antioxidant activity (using the DPPH (2,2-Diphenyl-1-picrylhydrazyl (DPPH) method), sweetness intensity (using 9-scales rating test), sensory acceptance (using 9-point hedonic test), and sensory profile (using CATA/Check-All-That-Apply). Substituting sugar with CP significantly increased moisture content, antioxidant activity, and hedonic acceptance but significantly decreased the total sugars and calories. However, no significant effects were observed on hardness, water activity, and protein content. Based on the De Garmo effectiveness index, 15% sugar substitution with CP (F2) resulted in the optimum MJC formulation having moisture content 30.71%, protein content 12.59%, total Brix (sugar) 62.00%, total calories 277.04 kcal/100 g, hardness 13.47 N, lightness (L*) 34.63, water activity 0.90, antioxidant activity 83.13%, and the overall liking score 5.34 (neither like nor dislike). The F2 had medium sweetness intensity (5.54), which was not statistically different from the control. The F2 sensory profile was in the opposite quadrant against control and positively correlated with cinnamon taste and aroma, which were also highly associated with product liking. This result indicates that CP is promising as a sugar substitute and to improve the sensory acceptance of MJC by masking the undesirable moringa flavor.

Assessment the Effects of Psyllium and Hydrocolloids in Gluten-free Noodle

This study was performed to examine the effects of individual and combined usage of psyllium with guar gum (GG) or locust bean gum (LBG) on the production of gluten-free Turkish-type noodles. For this purpose, six different formulations were created with the total amount of variables being 3%, and samples' physical, chemical, cooking, textural and sensorial properties were performed. The results revealed no significant decrease or increase in moisture, ash, protein and fat contents. On the other hand, although individual usage of psyllium caused a slight decrease in carbohydrate content, this did not reflect energy values. The lowest L* and hue and the highest a* values were observed in the samples where only psyllium was used, and there was no statistically significant difference in b* and saturation index values. Regarding cooking quality and textural analysis, the results from these two analyses supported each other, and there is a significant difference between the samples. An additional disliking that can be considered statistically significant was not determined by using psyllium with or without other gums in noodle formulation. As a result, the dual combined psyllium with other gums in gluten-free noodle production could be appropriate without adversely affecting the quality of the product.

Study on failure characteristics and evaluation index of aquifer shale based on energy evolution

AbstractThe presence of abundant clay components and microporous structure in shale results in its high hydrophilicity, making a water-rich environment inevitable in petroleum exploration projects. Therefore, it is crucial to consider the influence of bedding structure, moisture content, confining pressure, and their combined effects on the geomechanical properties of shale. This article aims to investigate the mechanical properties of deep shale under varying water content conditions, elucidate the failure mode and failure mechanism of shale in actual engineering scenarios, and explores the interplay between stress, structure, moisture content, and other factors on its mechanical properties. The evaluation of wellbore stability and fracture propagation effects is proposed based on laboratory experiments using triaxial stress and strain data, along with the application of energy evolution theory. The experimental procedures encompass an analysis of shale's microscopic components and structure, as well as anisotropic shale triaxial compression tests conducted under different moisture contents and confining pressures. The results demonstrate that shale exhibits dense pores in its microstructure and displays pronounced anisotropic characteristics in its macrostructure. The presence of water within these pores, combined with the in situ stress within the formation, significantly influences the mechanical properties of shale. This anisotropy decreases with increasing moisture content, but the mechanical performance still decreases. Under triaxial compression conditions, the increase in confining pressure to some extent enhances the anisotropy of shale's deformation characteristics, which is related to the failure modes of shale. However, the detrimental effect of moisture content on shale's mechanical properties still persists. In order to quantify the impact of these factors, this study utilizes the elastic modulus as an indicator of the coupling effect. It combines the triaxial strain curve obtained from laboratory tests and proposes an evaluation index for shale mechanical properties based on the energy evolution theory. This index is suitable for assessing wellbore stability (the stability index called SIr) and crack expansion (the brittleness index called BIr). The calculation results reveal that, during the wellbore drilling process, excavating parallel to the direction of shale bedding while maintaining low moisture content and high confining pressure yields a higher SIr value, indicating better wellbore stability. On the other hand, during reservoir fracturing, fracturing perpendicular to the shale bedding direction and maintaining low confining pressure and moisture content result in a smaller BIr value. This approach is more beneficial for the expansion of shale fracture network in engineering.

Study on the Influence of Moisture Content and Void Ratio on the Disintegration of Red Clay

Guilin is a famous karst area, and currently the view that the disintegration of red clay will cause soil cave collapse is increasingly recognized. In order to study the influence of the coupling effect of moisture content and void ratio on the disintegration of red clay, different moisture contents and void ratios of Guilin red clay were placed on a self-made disintegration apparatus to record the real-time disintegration amount and observe the disintegration phenomenon. Images of the structural characteristics of soil were obtained by a scanning electron microscope (SEM). Additionally, nuclear magnetic resonance (NMR) was applied to analyze the distribution of water in both natural and saturated states. The results show that the disintegration rate of red clay decreases as the initial moisture content increases, but increases with the increase of void ratio. Both moisture content and void ratio affect the structural characteristics of red clay. When the moisture content remains constant, the soil changes from a three-peak to a two-peak structure as the void ratio increases. The total area and secondary peak area of the T2 spectrum increase, while the starting T2 value of the main peak shifts to the right and the area decreases. Meanwhile, the starting T2 value of the secondary peak shifts to the right and the area increases. When the void ratio remains constant, the starting T2 value of the main peak gradually shifts to the left and the area decreases as the moisture content increases. However, the starting T2 value of the secondary peak shifts to the right and the area decreases or first decreases and then increases. The disintegration rate does not exhibit a significant relationship with either pore volume or macropore volume. The combined water saturation shows a bilinear relationship with both the moisture content and void ratio, where it increases as the initial moisture content increases, but decreases as the void ratio increases, with a correlation coefficient of 0.9929. The disintegration rate has an exponential relationship with the combined water saturation, and it decreases as the combined water saturation increases, with a correlation coefficient of 0.9934.