Ground vibrations from operating railway in tunnels is a significant obstacle to sustainable development of subway. The backfill grouting layer, formed during shield tunneling, serves as a critical medium in propagation of tunnel vibrations, highlighting its potential in vibration mitigation. A semi-analytical model for the tunnelgrouting layer-soil system is proposed in this study, in order to clarify the influence of backfill grouting layer on the dynamic responses in a half-space, subjected to tunnel vibrations. In establishment of the closed-form solution, the tunnel and grouting layer are considered as two nested hollow cylinders embedded in a halfspace, with applying the Fourier transform and wave transformation. As a validation, the numerical results from the proposed semi-analytical model are compared with those reported in literature. Parametric studies, with respect to the geometric configuration (i.e., the thickness) and material parameters (i.e., the Young's modulus, material damping, and density) of the backfill grouting layer in the mitigation of tunnel vibrations, are carried out. It is found that incorporation of the backfill grouting layer significantly changes the dynamic responses of the soil and, by appropriately designing its material parameters, especially the Young's modulus, effective mitigation of tunnel vibrations can be achieved.

Chromium (Cr) contamination poses food safety and environmental challenges, yet the early-stage physiological and molecular responses to Cr(III) stress remain unclear. Citrus and tomato are economically important crops representing woody and herbaceous species, making them valuable models for studying heavy metal toxicity in plants. This study investigates the impact of Cr (III) exposure on citrus and tomato seedlings, with a focus on physiological phenotypes and transcriptional response. Citrus seed germination declines with increasing Cr(III) concentrations, while low Cr(III) levels promote tomato germination, with inhibition occurring above 1 g/L. Under hydroponic conditions, Cr (III) severely hampers root and leaf growth in both citrus and tomato plants, accompanied by decreased net photosynthetic rate. Using a GFP-based confocal microscopy system, we observed reduced fluorescence intensity within three days of Cr(III) exposure (100 mg/L and 500 mg/L), indicating early cellular damage. Biochemical assays revealed oxidative stress, marked by increased H2O2, malondialdehyde (MDA), and antioxidant enzyme activity. Additionally, low Cr (III) concentrations could result in the death of various microorganisms, including Escherichia coli, Agrobacterium rhizogenes, and Agrobacterium tumefaciens. Transcriptomic analysis identified differentially expressed genes related to MAPK signaling pathway and Plant hormone signal transduction pathway. Transcription of many transcription factors, such as bHLH, WRKY, and MYB, also underwent significant changes.

The stress state is the fundamental for evaluating the soil strength and stability, playing a crucial role. However, during the stress testing, local damage and other uncertain factors may lead to partial sensor data missing, causing the existing three-dimensional stress calculation method to fail. To accurately restore the soil stress state during data missing, a three-dimensional stress calculation method was developed based on three-dimensional stress testing principles, incorporating axisymmetric and one-dimensional compression characteristics. The three-dimensional stress, principal stress , the first invariant of stress I-1, the second in variant of stress J(2) and stress Lode angle of a sandy soil foundation under one-dimensional compression conditions with different data missing were calculated and compared to results with complete data. The results show that the method is highly accurate; as the load increases, the relative error decreases and converges. The principal stresses, the first invariant of stress I-1, the second invariant of stress J(2) and the stress Lode angle align with one-dimensional compression response, suggesting that this calculation method supports advanced data mining. This study offers a novel approach and a practical method for fully utilizing the test data.

A series of undrained cyclic torsional shear tests were conducted to investigate the effect of cyclic loading frequency on the liquefaction characteristics of saturated sand using the hollow cylinder apparatus. The test results show that the dilative and contractive tendencies of various saturated sands are not only related to the physical properties of sand, but also affected by loading frequency. Under low-frequency loading, the saturated sand has a dilative behaviour, excess pore water pressure fluctuates after initial liquefaction and soil maintains the ability to resist liquefaction to some extent after the initial liquefaction. The liquefaction mode in terms of stress-strain relationship generally performs as the cyclic mobility. However, under the high-frequency loading, the saturated sand has a contractive behaviour, excess pore water pressure generally keeps stable after the initial liquefaction. The liquefaction mode in terms of stress-strain relationship generally exhibits as cyclic instability. The deformation caused by low-frequency loading is significantly larger compared with that caused by high-frequency loading. At higher loading frequencies, the phase transformation stress ratio increases with the increase of loading frequency, and gradually approaches the failure stress ratio.

Drought and soil salinization significantly constrain agricultural productivity, driving the need for molecular breeding strategies to enhance stress resistance. Zinc finger proteins play a critical role in plant response to abiotic stress. In this study, a gene encoding a C2H2-type zinc finger protein (AfZFP5) was cloned from Amorpha fruticosa, a species known for its strong adaptability. qRT-PCR analysis revealed that AfZFP5 expression is regulated by sorbitol, H2O2, NaCl, and NaHCO3. And all four treatments can cause upregulation of AFZFP5 expression in the roots or leaves of Amorpha fruticosa within 48 h. Transgenic tobacco lines overexpressing AfZFP5 demonstrated enhanced tolerance to drought and salt-alkali stress at germination, seedling, and vegetative stages. Compared to wild-type plants, transgenic lines exhibited significantly higher germination rates, root lengths, and fresh weights when treated with sorbitol, NaCl, and NaHCO3. Under natural drought and salt-alkali stress conditions, transgenic plants showed elevated activities of superoxide dismutase (SOD) and peroxidase (POD), and upregulated expression of oxidative stress-related kinase genes (NtSOD, NtPOD) during the vegetative stage. Additionally, transgenic tobacco displayed lower malondialdehyde (MDA) content and reduced staining levels with 3,3 ' diaminobenzidine (DAB) and Nitro blue tetrazolium (NBT), indicating enhanced reactive oxygen species (ROS) scavenging capacity by AfZFP5 upon salt-alkali stress. Under simulated drought with PEG6000 and salt-alkali stress, chlorophyll fluorescence intensity and Fv/Fm values in transgenic tobacco were significantly higher than in wild-type plants during the vegetative stage, suggesting that AfZFP5 mitigates stress-induced damage to the photosynthetic system. This study highlights the role of AfZFP5 in conferring drought and salt-alkali stress tolerance, providing genetic resources and a theoretical foundation for breeding stress-resistance crops.

In this paper, a new approach for rotational hardening in elastic-plasticity is formulated. After discussing the standard yield criteria employed for geomaterials and the rotational hardening models proposed in the past, the authors introduce the concept of pure rotational hardening, that is a rigid rotation of the yield surface not implying any distortion of it. In the second part of the paper, a new approach for rotational hardening, based on Householder transformations, is proposed. The method, that allows to reflect vectors with respect to a given hyper-plane, is briefly described since not usually employed in geomechanics. Moreover, the authors clarify that any yield surface or plastic potential rotation, not being a rolling, is a transformation keeping unaltered first and second invariants, but not the third. As a consequence, when rotational hardening is introduced, the use of the third mixed invariant, for defining in the deviatoric plane the yield surface shape, is not appropriate. Finally, the application of the proposed approach in the formulation of anisotropic elastic-plastic strain hardening constitutive models is briefly discussed for the classes of uncoupled and hybrid yield criteria that include a dependence of the yield surface on Lode angle.

Heavy metals (HM) are toxic to the microbiota of agricultural soils because they affect the development of bacteria and fungi that promote plant growth and are agents of biological control of pathogenic organisms. In this regard, fungi ofthe genus Trichoderma have these functions in plants, but like other organisms, HM affects their growth and biological activity. This article reviews the lithogenic and anthropogenic sources of generation of HM Cu, Cr-VI, Pb, and Cd, the tolerance mechanisms, and the antioxidant response to oxidative damage in Trichoderma caused by HM. It was identified that in some agricultural soils, the HM content increases mainly due to irrigation with wastewater and the intensive use of agrochemicals, such as pesticides and fertilizers. In Trichoderma, the tolerance mechanisms to Cu, Cr-VI, Pb, and Cd include biosorption, bioaccumulation, and biotransformation. In contrast, studies of the antioxidant response of Trichoderma to oxidative stress caused by MP are scarce. In the case of Cu and Cr, a relationship between changes in antioxidant enzyme activity and a decrease in the oxidation of cell membrane lipids is reported. This represents an opportunity to understand the toxic effect of MP on fungi of the genus Trichoderma, which is part of the biotic soil community.

The prerequisite for breeding a plant to be used in phytoremediation is its high tolerance to grow normally in soil contaminated by certain heavy metals. As mechanisms of plant uptake and transport of nickel (Ni) are not fully understood, it is of significance to utilize exogenous genes for improving plant Ni tolerance. In this study, rcnA from Escherichia coli encoding an exporter of Ni and cobalt was overexpressed constitutively in Arabidopsis thaliana, and the performance of transgenic plants was assayed under Ni stress. The subcellular localization of rcnA in plant cells was found to be the plasma membrane. Constitutive overexpression of rcnA in Arabidopsis rendered better growth of either seedlings on agar medium containing 85, 100, and 120 mu M NiCl2 or adult plants in a nutrient solution with 5 mM NiCl2 added. Compared to the wildtype, rcnA-OE transgenic plants under Ni stress accumulated lower levels of reactive oxygen species (i.e., superoxide and hydrogen peroxide) in leaves and exhibited less oxidative damage in shoots, as demonstrated by less electrolyte leakage and the lower malondialdehyde content. Notably, rcnA-OE transgenic plants retained a higher content of Ni in roots and had a lower content of Ni in shoots. Therefore, our findings indicated that the bacterial rcnA gene may be utilized to improve plant Ni tolerance through genetic transformation.

When constructing on clay and gyttja soils, low-carbon ground improvement methods such as preloading should be preferred over carbon-intensive solutions (e.g., piles or deep mixing with lime-cement binder). The design of preloading requires knowledge about the compressibility and consolidation properties of subsoil, but site-specific oedometer tests may be scarce or even lacking, especially in the early design phases. Hence, this paper presents two extensive databases based on oedometer tests performed on Finnish clay and gyttja soils, with a special emphasis on consolidation rate and creep properties. The FI-CLAY-oedo/14/282 database contains 282 oedometer test-specific data entries, such as initial hydraulic conductivity and maximum creep coefficient. The second database, FI-CLAY-cv/8/774, contains 774 load increment-specific data entries (e.g., coefficient of consolidation) from 232 oedometer tests. The analysis of these databases provided three main results: (i) statistics for bias factors, which quantify the differences between determination methods (log time vs. square root time method and oedometer vs. falling head test), (ii) transformation models (and their transformation uncertainty) to predict creep coefficient from index or consolidation properties, and (iii) typical value distributions for various consolidation rate and creep properties, in a form of histograms and fitted lognormal distributions. All the results are given with statistical information, which allows their straightforward utilization as input data for probabilistic assessment (reliability-based design). It is concluded that the consolidation properties of clay and gyttja soils are indeed characterized by significant uncertainty. Hence, such results are recommended to be used as existing (prior) knowledge when determining design parameters, either by supporting engineering judgement or via a more systematic framework such as Bayesian statistics.

An approach based on a Physics-Informed Neural Network (PINN) is introduced to tackle the two-dimensional (2D) rheological consolidation problem in the soil surrounding twin tunnels with different cross-sections, under exponentially time-growing drainage boundary. The rheological properties of the soil are modelled using a generalized viscoelastic Voigt model. An enhanced PINN-based solution is proposed to overcome the limitation of traditional PINNs in solving integral-differential equations (IDEs) equations. In particular, two key elements are introduced. First, a normalization method is employed for the spatio-temporal coordinates, to convert the IDEs governing the consolidation problem into conditions characterized by unit-duration time and unit-area geometric domain. Second, a conversion method for integral operators containing function derivatives is devised to further transform the IDEs into a set of second-order constant-coefficient homogeneous linear partial differential equations (PDEs). By using the TensorFlow framework, a series of PINN-based models is developed, incorporating the residual adaptive sampling method to address the 2D consolidation equations of soft soils surrounding tunnels with different burial depths and cross-sections. Comparative analyses between the PINNbased solutions, and either finite element or analytical solutions highlight that the aforementioned normalization stage empowers PINNs to solve the PDEs across different spatial and temporal scales. The integral operator transformation method facilitates the utilization of PINNs for solving intricate IDEs.