In the northwestern saline soils and coastal areas, cement soil (CS) materials are inevitably subjected to various factors including salt erosion, dry-wet cycle (DWC), temperature fluctuations and dynamic loading during its service life, which the coupling effect of these unfavourable factors seriously threatened the durability and engineering reliability of CS materials. Additionally, combined with the substantially extensive application prospects of rubber cementitious material, as a resource-efficient civil engineering material and fibre-reinforced composites, consequently, in order to address aforementioned issues, this investigation proposed to consider the incorporation of rubber particles composite basalt fiber (BF) to CS materials as an innovative engineering solution to effectively enhance the mechanical and durability properties of CS materials for prolonging its service life. In this study, sulphate ions were utilized to simulate external erosive environment and basalt fibre rubber cement soil (BFRCS) specimens were subjected to various DWC numbers (0, 1, 4, 7, 11 and 15) in diverse concentrations (0 g/L, 6 g/L and 18 g/L) of Na2SO4 solution, and specimens that had completed the corresponding DWC number were then conducted both unconfined and dynamic compressive strength tests simultaneously to analyze static and dynamic stress-strain curves, static and dynamic compressive strength, apparent morphological deterioration characteristics and energy absorption properties of BFRCS specimens. Furthermore, further qualitative and quantitative damage assessments of pore distribution and microscopic morphology of BFRCS specimens under various DWC sulphate erosion environments were carried out from the fine and microscopic perspectives through pore structure test and scanning electron microscopy (SEM) test, respectively. The test results indicated that the static, dynamic compressive strength and specific energy absorption (SEA) of BFRCS specimens exhibited a slight increase followed by a progressive decline as DWC number increased. Additionally, compared to 4 mm BFRCS specimens, those with 0.106 mm rubber particle size demonstrated more favorable resistance to DWC sulphate erosion. The air content, bubble spacing coefficient and average bubble chord length of BFRCS specimens all progressively grew as DWC number increased, while the specific surface area of pores gradually decreased. The effective combination of BF with CS matrix significantly diminished pores and weak areas within specimen, and its synergistic interaction with rubber particles efficiently mitigated the stresses associated with expansive, contraction, crystallization and osmosis subjected by specimen. Simultaneously, more ettringite (AFt) had been observed within BFRCS specimens in 18 g/L sulphate erosive environments. These findings will facilitate the design and construction of CS subgrade engineering in northwestern saline soils and coastal regions, promoting sustainable and durable solutions while reducing the detrimental environmental impact of waste rubber.

Small organic compounds (SOCs) are widespread environmental pollutants that pose a significant threat to ecosystem health and human well-being. In this study, the FrmA gene from Escherichia coli was overexpressed alone or in combination with FrmB in Arabidopsis thaliana and their resistance to multiple SOCs was investigated. The transgenic plants exhibited varying degrees of increased tolerance to methanol, formic acid, toluene, and phenol, extending beyond the known role of FrmA in formaldehyde metabolism. Biochemical and histochemical analyses showed reduced oxidative damage, especially in the FrmA/BOE lines, as evidenced by lower malondialdehyde (MDA), H2O2 and O-2(center dot-) levels, indicating improved scavenging of reactive oxygen species (ROS). SOC treatment led to significantly higher levels of glutathione (GSH) and, to a lesser extent, ascorbic acid (AsA) in the transgenic plants than in the wild-types. After methanol exposure, GSH levels increased by 95 % and 72 % in the FrmA/BOE and FrmAOE plants, respectively, while showing no significant increase in the wild-type plants. The transgenic plants also maintained higher GSH:GSSG and AsA:DHA ratios, exhibited upregulated glutathione reductase (GR) and dehydroascorbate reductase (DHAR) activities, and correspondingly increased gene expression. In addition, the photosynthetic parameters of the transgenic plants were less affected by SOC stress, which represents a significant photosynthetic advantage. These results emphasize the potential of genetically engineered plants for phytoremediation and crop improvement, as they exhibit increased tolerance to multiple hazardous SOCs. This research lays the foundation for sustainable approaches to combat pollution and improve plant resilience in the face of escalating environmental problems.

Integral bridges with longer spans experience an increased cyclic interaction with their granular backfills, particularly due to seasonal thermal fluctuations. To accurately model this interaction behaviour under cyclic loading, it is crucial to employ appropriate constitutive models and meticulously calibrate and test them. For this purpose, in this paper two advanced elastoplastic (DeltaSand, Sanisand-MS) and two hypoplastic (Hypo+IGS, Hypo+ISA) constitutive models with focus on small strain and cyclic behaviour are investigated. The soil models are calibrated based on a comprehensive laboratory programme of a representative highly compacted gravel backfill material for bridges. The calibration procedure is shown in detail and the model capabilities and limitations are discussed on the element test level. Additional triaxial tests with repeated un- and reloading reveal significant over- and undershooting effects for the majority of the investigated material models. Finally, cyclic finite element analyses on the soil-structure interaction of an integral bridge are conducted to compare the performance of the soil models. Qualitatively similar cyclic evolution of earth pressures are detected for the soil models at various bridge lengths and test settings. However, a substantially different cyclic settlement behaviour is observed. Additionally, the investigation highlights severe overshooting effects associated with the tested hypoplastic soil models. This phenomenon is studied in detail using a single integration point analysis. Supplementary studies reveal that the foot point deformation of the abutment significantly influences the lateral passive stress mobilisation and the amount of its increase with growing seasonal cycles.

Controlled low-strength material (CLSM) is a flowable, self-leveling backfill material used as an alternative to compacted soil for backfilling trenches, retaining walls, underground cavities, and in pavement construction. This study aims to investigate the permanent deformation of CLSM reinforced with basalt fibers. Basalt fibers with lengths of 6 and 24 mm are incorporated into CLSM mixtures to assess their impact on flowability, setting times, and mechanical properties. Mechanical testing indicates that longer fibers improve tensile strength through a bridging effect. Repeated load triaxial tests are conducted to evaluate the permanent strain behavior under repeated loading. The results show that permanent strain increases with the deviator stress and number of loading cycles. A regression model accounting for the number of loading cycles and deviator stress provides accurate permanent-strain predictions, and the permanent strain behaviors are classified based on the refined shakedown theory. Therefore, the basalt-fiber-reinforced CLSM suggested in this study may be suitable for pavement base material due to its relatively low permanent strain under typical stress conditions.

Landslides developing in bedding-plane sediments are predominantly controlled by basal shear zones, where clay-rich materials localize deformation along bedrock surfaces. The mechanical behavior of shear-zone soil is further influenced by the characteristics of soil-rock interface. This paper investigates the residual strength of the soil-rock interface samples through ring shear and large-scale direct shear tests under varying stress and rate conditions. Shear zone materials from two landslides sites are paired with manufactured base and natural rock to compose the interface samples. Experimental results find that the residual strengths of shear zone materials are altered by different interfaces. At a low normal stress level, the mechanical behaviors of soils show strong dependence on surface asperities. As driven by increasing shear stress, the smooth interface sample exhibits accelerated failure progression with significant loss of resistance. The surface morphology and rheological behavior explain that the basal shearing easily occur along a relatively smooth interface, resulting weakening at high velocity and stress states.

While traditional methods of soil stabilization using cement or lime have been extensively researched, there is a notable gap in understanding the mechanical behavior of soil stabilized with innovative materials. This study aims to investigate the mechanical properties of soil stabilized with polyurethane (PU) foam, nanosilica, and basalt fiber. Unconfined compressive strength (UCS) and direct shear tests were conducted on reconstituted silica and calcareous samples treated with various combinations of these additives. Various parameters, including additive content, curing time, and freeze-thaw cycles, were thoroughly examined. The findings demonstrate a significant increase in UCS and shear strength parameters (c and phi) with the addition of PU foam, nanosilica, or their combination with fiber. Notably, the combination of PU and basalt fiber exhibits the most promising performance in improving the mechanical behavior and freeze-thaw durability of silica and calcareous sand, especially for short curing times. Additionally, calcareous samples consistently exhibit higher UCS, and shear strength compared to silica samples. Furthermore, the analysis of failure patterns and the microstructure of the samples using scanning electron microscopy provides insights into the effectiveness of these stabilizing agents and their influence on the mechanical properties of the soil.

The use of basalt fibers, which are employed in various fields, such as construction, automotive, chemical, and petrochemical industries, the sports industry, and energy engineering, is also increasingly common in soil reinforcement studies, another application area of geotechnical engineering, alongside their use in concrete. With this growing application, scientific studies on soil reinforcement with basalt fiber have also gained momentum. This study establishes the effects of basalt fiber on the liquid limit, plastic limit, and strength properties of soils, and the relationships among the liquid limit, plastic limit, and unconfined compressive strength of the soil. For this purpose, 12 mm basalt fiber was used as a reinforcement material in kaolin clay at ratios of 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%. The prepared samples were subjected to liquid limit, plastic limit, and unconfined compressive strength tests. As a result of the experimental studies, the fiber ratio that provided the best improvement in the soil properties was determined, and the relationships among the liquid limit, plastic limit, and unconfined compressive strength were established. The experimental results were then used as input data for an artificial intelligence model. The used neural network (NN) was trained to obtain basalt fiber-to-kaolin ratios based on the liquid limit, plastic limit, and unconfined compressive strength. This model enabled the prediction of the fiber ratio that provides the maximum improvement in the liquid limit, plastic limit, and compressive strength without the need for experiments. The NN results were in great agreement with the experimental results, demonstrating that the fiber ratio providing the maximum improvement in the soil properties can be identified using the NN model without requiring experimental studies. Moreover, the performance and reliability of the NN model were evaluated using 5-fold cross-validation and compared with other AI methods. The ANN model demonstrated superior predictive accuracy, achieving the highest correlation coefficient (R = 0.82), outperforming the other models in terms of both accuracy and reliability.

Soil salinization severely restricts the growth and development of crops globally, especially in the northwest Loess Plateau, where apples constitute a pillar industry. Nanomaterials, leveraging their unique properties, can facilitate the transport of nutrients to crops, thereby enhancing plant growth and development under stress conditions. To investigate the effects of nano zinc oxide (ZnO NP) on the growth and physiological characteristics of apple self-rooted rootstock M9-T337 seedlings under saline alkali stress, one-year-old M9-T337 seedlings were used as experimental materials and ZnO NPs were used as donors for pot experiment. Six treatments were set up: CK (normal growth), SA (saline alkali stress,100 mmol/L NaCl + NaHCO3), T1 (saline alkali stress + 50 mg/L ZnO NPs), T2 (saline alkali stress + 100 mg/L ZnO NPs), T3 (saline alkali stress + 150 mg/L ZnO NPs) and T4 (saline alkali stress + 200 mg/L ZnO NPs). The results were found to show that saline alkali stress could significantly inhibit the growth and development of M9-T337 seedlings, reduce photosynthetic characteristics, and cause ion accumulation to trigger osmotic regulation system, endogenous hormone and antioxidant system imbalances. However, the biomass, plant height, stem diameter, total leaf area and leaf perimeter of M9-T337 seedlings were significantly increased after ZnO NP treatment. Specifically speaking, ZnO NPs can improve the photosynthetic capacity of M9-T337 by increasing the content of photosynthetic pigment, regulating photosynthetic intensity and chlorophyll fluorescence parameters. ZnO NPs can balance the osmotic adjustment system by increasing the contents of soluble protein (SP), soluble sugar (SS), proline (Pro) and starch, and can also enhance the activities of enzymatic (SOD, POD, and CAT) and non-enzymatic antioxidant enzymes (APX, AAO, GR, and MDHAR) to enhance the scavenging ability of reactive oxygen species (H2O2, O2 center dot-), ultimately reducing oxidative damage; ZnO NPs promoted the growth of M9-T337 seedlings under saline alkali stress by synergistically responding to auxin (IAA), gibberellin (GA3), zeatin (ZT) and abscisic acid (ABA). Additionally, the Na+/K+ ratio was reduced by upregulating the expression of Na+ transporter genes (MdCAX5, MdCHX15, MdSOS1, and MdALT1) and downregulating the expression of K+ transporter genes (MdSKOR and MdNHX4). After comprehensive analysis of principal components and correlation, T3 (150 mg/L ZnO NPs) treatment possessed the best mitigation effect. In summary, 150 mg/L ZnO NPs(T3) can effectively maintain the hormone balance, osmotic balance and ion balance of plant cells by promoting the photosynthetic capacity of M9-T337 seedlings, and enhance the antioxidant defense mechanism, thereby improving the saline alkaline tolerance of M9-T337 seedlings.

Microplastics (MP) pollution in agricultural soils has become an important environmental problem. Phosphorus (P) is a key nutrient for plant growth. P fertilizers are mainly applied to agricultural fields to achieve the high production expected by farmers. The experiment included two MP levels (0, 1 % w/w) and two P levels (0 mg kg(-1) , 200 mg kg(-1) ) in order to know whether MP effects on wheat and maize are regulated by supplemental P supply. MP decreased plant height, photosynthetic pigment, and chlorophyll fluorescence parameters, while increased ROS and MDA contents. Wheat and maize exhibited distinct strategies in mitigating growth damage caused by MP pollution: wheat primarily increased the AsA contents, while maize predominantly enhanced APX activity. P supply alleviated the MP pollution effect by improving photosynthetic pigments, POD, and PPO activity in wheat and maize. P supply alleviated the MP pollution effect by improving antioxidant enzyme activities in the AsA-GSH cycling in wheat, while increasing non-enzymatic antioxidant contents in the AsA-GSH cycling in maize. The results showed that wheat and maize resisted MP pollution by different mechanisms, and P supply reduced the sensitivity of wheat and maize to MP pollution and its regulatory effect on wheat was better than that on maize. Synopsis: The response of different plants under the same microplastic and phosphorus conditions is limited. We find phosphorus alleviates microplastics pollution on wheat and maize through different regulatory routes.

The reverse-consolidation caused by excavation inevitably affects the bearing capacity of basal soil to resist water pressure in confined aquifers, posing a risk to excavation stability. However, there is still a lack of efficient solutions to incorporate the layered heterogeneity into the analysis of the reverse-consolidation. This study proposes a practical approach where the spectral Galerkin method is used to capture the variation of soil properties with depth. The boundaries are characterized by time-dependent drainage boundary conditions to simulate the excavation process. The excess pore-water pressure profile is described by a single expression calculated by common matrix operations. The rationality and accuracy of the practical approach are verified by existing analytical models and field data. Subsequently, the permeability coefficient variability, relatively impervious interlayer, and sand interlayer are analyzed to illustrate their effects on the reverse-consolidation behavior of basal soil. Results indicate that the distribution of excess pore-water pressure is significantly influenced by the variability and distribution form of the permeability coefficient. The relatively impervious interlayer delays the dissipation of excess pore-water pressure and bears a large hydraulic gradient, while the sand interlayer is the opposite. These above influences become more significant as the excavation progresses due to the time effect.