Bedrock-soil layer slopes (BSLSs) are widely distributed in nature. The existence of the interface between bedrock and soil layer (IBSL) affects the failure modes of the BSLSs, and the seismic action makes the failure modes more complex. In order to accurately evaluate the safety and its corresponding main failure modes of BSLSs under seismic action, a system reliability method combined with the upper bound limit analysis method and Monte Carlo simulation (MCS) is proposed. Four types of failure modes and their corresponding factors of safety (Fs) were calculated by MATLAB program coding and validated with case in existing literature. The results show that overburden layer soil's strength, the IBSL's strength and geometric characteristic, and seismic action have significant effects on BSLSs' system reliability, failure modes and failure ranges. In addition, as the cohesion of the inclination angle of the IBSL and the horizontal seismic action increase, the failure range of the BSLS gradually approaches the IBSL, which means that the damage range becomes larger. However, with the increase of overburden layer soil's friction angle, IBSL's depth and strength, and vertical seismic actions, the failure range gradually approaches the surface of the BSLS, which means that the failure range becomes smaller.

Earthquakes are common geological disasters, and slopes under seismic loading can trigger coseismic landslides, while also becoming unstable due to accumulated damage caused by the seismic activity. Reinforced soil slopes are widely used as seismic-resistant geotechnical systems. However, traditional geosynthetics cannot sense internal damage in reinforced soil systems, and existing in-situ distributed monitoring technologies are not suitable for seismic conditions, thus limiting accurate post-earthquake stability assessments of slopes. This study presents, for the first time, the use of a batch molding process to fabricate self-sensing piezoelectric geogrids (SPGG) for distributed monitoring of soil behavior under seismic conditions. The SPGG's reinforcement and damage sensing abilities were verified through model experiments. Results show that SPGG significantly enhances soil seismic resistance and can detect soil failure locations through voltage distortions. Additionally, the tensile deformation of the reinforcement material can be quantified with sub-centimeter precision by tracking impedance changes, enabling high-precision distributed monitoring of reinforced soil under seismic conditions. Notably, when integrated with wireless transmission technology, the SPGG-based monitoring system offers a promising solution for real-time monitoring and early warning in road infrastructure, where rapid detection and response to seismic hazards are critical for mitigating catastrophic outcomes.

Expansive soil, characterized by significant swelling-shrinkage behavior, is prone to cracking under wet-dry cycles, severely compromising engineering stability. This study combines experimental and molecular dynamics (MD) simulation approaches to systematically investigate the improvement effects and micromechanisms of polyvinyl alcohol (PVA) on expansive soil. First, direct shear tests were conducted to analyze the effects of PVA content (0 %-4 %) and moisture content (30 %-50 %) on the shear strength, cohesive force, and internal friction angle of modified soil. Results show that PVA significantly enhances soil cohesive force, with optimal improvement achieved at 3 % PVA content. Second, wet-dry cycle experiments revealed that PVA effectively suppresses crack propagation by improving tensile strength and water retention. Finally, molecular dynamics simulations uncovered the distribution of PVA between montmorillonite (MMT) layers and its influence on interfacial friction behavior. The simulations demonstrated that PVA forms hydrogen bonding networks, enhancing interlayer interactions and frictional resistance. The improved mechanical performance of PVAmodified soil is attributed to both nanoscale bonding effects and macroscale structural reinforcement. This study provides theoretical insights and technical support for expansive soil stabilization.

Shallow cut-and-cover underground structures, such as subway stations, are traditionally designed as rigid boxes (moment-resisting connections between the main structural members), seeking internal hyperstaticity and high lateral (transverse) stiffness to achieve important seismic capacity. However, since seismic ground motions impose racking drifts, this proved rather prejudicial, with great structural damage and little resilience. Therefore, two previous papers proposed an opposite strategy seeking low lateral (transverse) stiffness by connecting the structural elements flexibly (hinging and sliding). Under severe seismic inputs, these structures would accommodate racking without significant damage; this behaviour is highly resilient. The seismic resilience of this solution was numerically demonstrated in the well-known Daikai station (Kobe, Japan) and a station located in Chengdu (China). This paper is a continuation of these studies; it aims to extend, deepen, and ground this conclusion by performing a numerical parametric study on these two stations in a wide and representative set of situations characterised by the soil type, overburden depth, engineering bedrock position, and high- and lowlateral-stiffness of the stations. The performance indices are the racking displacement and the structural damage (quantified through concrete damage variables). The findings of this study validate the previous remarks and provide new insights.

The thermo-mechanical (TM) behaviour of the energy pile (EP) group becomes more complicated in the presence of seepage, and the mechanism by which seepage impacts the EP group remains unclear.In the current work, a 2 x 2 scale model test bench of EP group was set up to investigate the TM behaviour of EP group with seepage. The test results indicate that the heat exchange performance of EP group with seepage can be significantly enhanced, but also leads to obvious differences in the temperature distribution of pile and surrounding soil along the seepage direction, and thus causes evident differences in the mechanical properties between the front pile and the back pile in pile group. Compared with the parallel connection form, the thermal performance of EP group with the series connection form is slightly attenuated. However, the mechanical properties of various piles in the EP group differ significantly. Under the action of seepage, the mechanical balance properties of various piles in the forward series form are optimal, followed by the parallel form, and the reverse series form is the least optimal. A 3-D CFD model was established to further obtain the influence of seepage and arrangement forms on EP group. The findings indicate that seepage can not only mitigate thermal interference between distinct piles but also expedite the process of heat transfer from pile-soil to reach a state of stability. Concurrently, the thermal migration effect induced by seepage will be superimposed along the seepage direction, resulting in the elevation of thermal interference of each pile along the seepage direction, and the superposition of thermal migration effect increases with the time. Under the same seepage condition, the cross arrangement can enhance the thermal performance of EP group, optimize the temperature distribution of pile and soil, and thus the imbalance of mechanical properties among pile groups can be reduced. In addition, the concepts of thermal interference coefficient and heat exchange rate per unit soil volume are introduced to facilitate a more precise evaluation of the thermal interference degree of each pile in the pile group and the heat exchange performance under different pile arrangement forms.The standard deviation and mean value in the statistical method are used to evaluate the equilibrium of mechanical properties of pile group, which is more intuitive to compare the differences in mechanical properties of pile groups under different working conditions.

Predictive modeling of dielectric heating in porous foods is challenging due to their nature as multiphase materials. To explore the relationship between the topological structure of multiphase foods and the accuracy of dielectric mixture models, the degree of anisotropy of two cooked rice samples with 26 and 32 % porosity was determined, and their dielectric properties were estimated using the Lichtenecker (LK), Landau-LifshitzLooyenga (LLL), and Complex Refractive Index Mixture (CRIM) equations. These properties were used in a predictive finite-element model for reheating an apparent homogeneous rice sample on a flatbed microwave (MW) for 120 s. The results were compared with experimental data and a validated two-element model. Unlike LK and LLL equations, the CRIM equation predicted heat accumulation towards the edges of the container at the two values of porosity ratio evaluated, in accordance with the experimental results and the isotropic nature of the sample. The simulated temperature distributions suggest that the three evaluated equations could predict the MW heating behavior of rice to some extent, but that in order to obtain more accurate results, it could be useful to obtain an empirical topology-related parameter specific for this sample. These results can provide insight on the relationship between the topology of the porous structure in the sample and the adequacy of different dielectric mixture models.

In view of the pollution of unpaved road dust in the current mines, this study demonstrated the excellent dust suppression performance of the dust suppressant by testing the dynamic viscosity, penetration depth and mechanical properties of the dust suppressant, and apply molecular dynamics simulations to reveal the interactions between substances. The results showed that the maximum dust suppression rate was 97.75 % with a dust suppressant formulation of 0.1 wt% SPI + 0.03 wt% Paas + NaOH. The addition of NaOH disrupts the hydrogen bonds between SPI molecules, which allows the SPN to better penetrate the soil particles and form effective bonding networks. The SPI molecules rapidly absorb onto the surface of soil particles through electrostatic interactions and hydrogen bonds. The crosslinking between SPI molecules connects multiple soil particles, forming larger agglomerates. The polar side chain groups in the SPN interact with soil particles through dipole-dipole interactions, further stabilizing the agglomerates and resulting in an enhanced dust suppression effect. Soil samples treated with SPN exhibited higher compressive strength values. This is primarily attributed to the stable network structure formed by the SPN dust suppressant within the soil. Additionally, the SPI molecules and sodium polyacrylate (Paas) molecules in SPN contain multiple active groups, which interact under the influence of NaOH, restricting the rotation and movement of molecular chains. From a microscopic perspective, the SPN dust suppressant further strengthens the interactions between soil particles through mechanisms such as liquid bridge forces, which contribute to the superior dust suppression effect at the macroscopic level.

The cracking during the drying process of thickened tailings stack is a critical issue impacting its stability. This study establishes a comprehensive analytical framework that encompasses both mechanism cognition and technical methodologies by systematically integrating multidimensional research findings. Research indicates that cracking results from the coupling effects of environmental parameters and process conditions. The environmental chamber, with its precise control over external conditions, has emerged as essential experimental equipment for simulating actual working environments. From a mechanical perspective, water evaporation induces volume shrinkage, leading to microcrack formation when local tensile stress surpasses the matrix's tensile strength, ultimately resulting in a network of interconnected cracks. This process is governed by the dual parameters of matric suction and tensile strength. In terms of theoretical modeling, the fracture mechanics model analyzes crack propagation laws from an energy dissipation standpoint, while the stress path analysis model emphasizes the consolidation shrinkage coupling effect. The tensile damage model is particularly advantageous for engineering practice due to its parameter measurability. In numerical simulation technology, the finite element method is constrained by the predetermined crack path, whereas the discrete element method can dynamically reconstruct the crack evolution process but encounters the technical challenge of large-scale multi-field coupling calculations. Research suggests that future efforts should focus on optimizing theoretical prediction models that account for the characteristics and cracking behavior of tailings materials. Additionally, it is essential to develop a comprehensive equipment system that integrates real-time monitoring, intelligent regulation, and data analysis. This paper innovatively proposes the establishment of a multi-scale collaborative research paradigm that integrates indoor testing, numerical simulation, and on-site monitoring. By employing data fusion technology, it aims to enhance the accuracy of crack predictions and provide both theoretical support and technical guarantees for the safety prevention and control of thickened tailings stacks throughout their entire life cycle.

A tensor-type capillary stress, instead of a scalar suction, has been proposed to serve as a stress-like state variable to capture the effects of capillarity in the mechanics of unsaturated granular soils. However, the influence of water content on the evolution of capillary stress in such soils remains insufficiently understood. This study performs numerical simulations of unsaturated granular soils in the pendular regime using the Discrete Element Method (DEM) involving a volume-controlled capillary bridge model. In these simulations, water content is maintained constant by redistributing the water from ruptured capillary bridges to adjacent ones. The evolution of capillary stress with varying water contents during triaxial and biaxial loading conditions is systematically examined. The DEM simulation results show that, under both loading conditions, the mean component of the capillary stress generally decreases, while its deviatoricity gradually develops. These changes are observed to become less significant as the initial degree of saturation increases. At low saturation levels, capillary bridges between non-contacting particle pairs rupture due to soil deformations, and the water from these ruptured bridges redistributes to existing contacts. This redistribution leads to an anisotropic distribution of pore water aligned with the contact network. At higher saturation levels, non-contacting capillary bridges persist due to their ability to sustain large relative displacements between particles, allowing the spatial distribution of pore fluids to remain less constrained by the solid contact network. Additionally, at higher water contents, relative sliding and particle rearrangement are the primary factors influencing the directional distribution of capillary bridges.

With the advantages of low construction costs and rapid installation, suction caissons are widely used as foundations in offshore engineering. This paper investigates the behavior of suction caisson foundations located in sandy soil under horizontal cyclic loads. The upgraded simple anisotropic sand constitutive model with memory surface (SANISAND-MS model) is employed to accurately capture the sand's cyclic behavior. To calibrate the parameters of the upgraded SANISAND-MS model, a series of triaxial drained monotonic and cyclic tests was performed. The effects of load idealization and loading sequence on the cyclic behavior of sand are studied based on the element test results, and the effects of load idealization on the cyclic response of suction caissons are studied from a finite-element simulation perspective. The triaxial test results indicate that load idealization slightly affects strain accumulation in both loose and dense sand. Based on simulation results, it is found that the loading sequence of load packages with varying amplitudes has a minor effect on the rotation accumulation of the suction caisson. The current load idealization method used in the engineering design practice of suction caissons is acceptable under drained conditions.