The Tibetan Railway has introduced pressures on the fragile grassland ecosystems of the Tibetan Plateau. However, the impact of the railway on the carbon sequestration remains unclear, as existing studies primarily focus on in-situ vegetation observations. In this study, we extracted the start and end of the growing season (SOS, EOS) and maximum daily GPP (GPPmax) along the railway corridor from the satellite-derived Gross Primary Productivity (GPP) data, and quantified the extent and intensity of the railway's disturbance on these indicators. We further employed the Statistical Model of Integrated Phenology and Physiology (SMIPP) to translate these disturbances into annual cumulative GPP (GPPann). Results show that Tibetan Railway significantly influences grassland within 50-meters, causing earlier SOS (0.1086 d m-1), delayed EOS (0.0646 d m-1), and reduced GPPmax (0.0069 gC m-2 d-1 m-1) as the distance to the railway gets closer. The advanced SOS and delayed EOS contributed gains of 28.82 and 104.26 MgC y-1, but reduction in GPPmax accounted for a loss of 2952.79 MgC y-1. Railway-induced phenology-physiology trade-off causes GPPann loss of 2819.71 MgC y-1. This study reveals Tibetan Railway's impact on grassland carbon cycling, offering insights for grassland conservation and sustainable transportation infrastructure projects.

The practice of widening levees to mitigate frequent river flooding is globally prevalent. This paper addresses the pressing issue of sand-filled widened levee failures under the combined effect of heavy rainfall and high riverine water levels, as commonly observed in practice. The primary objective is to illuminate the triggering mechanism and characteristics of such levee failures using the well-designed physical model experiment and Material Point Method (MPM), thus guiding practical implementations. Experimentally, the macro-instability of the levee, manifested as slope failure within the sand-filled widened section, is primarily triggered by changes in the stress regime near the levee toe and continuous creep deformation. Upon failure initiation, the levee slope experiences a progressive failure mode, starting with local sliding, followed by global sliding, and ultimately transitioning into a flow-like behaviour, which characterises the slide-to-flow failure pattern. The slope failure along the interface between the original and new levees is the result of shear deformation rather than the cause. Parametric studies conducted using the calibrated MPM model reveal a critical threshold for the widening width, beyond which the volume of sliding mass and travel angle exhibit no further variation. Increasing the cohesion of the river sand used for levee widening demonstrates the most pronounced improvement in levee stability in the face of the combined effect of intense rainfall and elevated river levels. The MPM-based evaluation of common slope protection measures demonstrates the superior protective benefits of grouting reinforcement and impervious armour layer protection, providing valuable insights for reinforcement strategies in levee engineering applications.

In silty (fine) sand aquifer, water-soil gushing (WSG) of shield tunnel may occur, causing structural damage and even collapse. A comprehensive understanding of the mechanism behind ground displacement and tunnel deformation during WSG in stratified soil was required for guiding disaster-relief in practice. In this article, the responses of ground and shield tunnel to WSG in stratified soil were investigated using a material-point method (MPM). First, a typical case of WSG in stratified soil was studied. By comparing the results with those of WSG in a homogeneous sand, both the ground and tunnel responses to WSG in a stratified soil were clarified. It was found that in stratified soil, the tunnel lining may deform first and then became stable, while in homogeneous sand, the tunnel deformation was shown to continuously develop with time due to unremitting soil loss. Then, the effects of the WSG locations, the sand layer position to tunnel, the layers number and permeability of clay and the discharge rate on WSG were further analyzed.

The frequent occurrence of extreme rainfall events often triggers levee slope failure (LSF), which, due to the levee effect, significantly damages the roads behind the levee. This paper presents a novel framework for the quantitative risk assessment of roads posed by LSF. Within the framework, the innovative integration of Monte Carlo simulation (MCS) and Material point method (MPM) provides a unique solution for simulating the complicated dynamic relationship between LSF and road destruction. MCS generates precise failure scenarios for MPM simulations, overcoming the limitations of traditional approaches in addressing uncertainty in complex scenario systems. With its technical superiority in capturing post-failure deformations, MPM offers critical insights for assessing road exposure and vulnerability. The framework also accounts for indirect losses from road disruptions, which have long been overlooked. The application of the framework to the risk assessment of the road behind the Shijiao Levee in the Pearl River Basin fully demonstrates its practicality and robustness. Compared to traditional risk assessment methods, the proposed framework provides a more refined dynamic evaluation, facilitating the formulation of more effective disaster mitigation strategies.

The lateral cyclic bearing characteristics of pile foundations in coastal soft soil treated by vacuum preloading method (VPM) are not well understood. To investigate, static lateral cyclic loading tests were conducted to assess the impact of treatment durations and sealing conditions on pile performance. Results indicated that vacuum preloading significantly improved soil properties, with undrained shear strength (S-u) increasing by up to 36.5 times, especially in shallow layers. Longer treatment durations boosted the ultimate lateral bearing capacity by up to 125%, although the effect decreased with depth, suggesting an optimal duration. Sealing conditions had minimal impact on capacity but affected S-u distribution and pile behaviour. Analysis of p-y curves revealed that longer durations improved soil resistance in shallow layers, while shorter durations provided consistent resistance across depths. Sealed conditions enhanced displacement capacity. The API specification predicted soil resistance accurately for lateral displacements under 0.1D but showed errors for larger displacements. These findings emphasise the need for optimising VPM parameters to enhance pile-soil interaction and lateral cyclic performance. The study offers guidance for applying VPM in soft soil foundation engineering and balancing performance with cost efficiency.

The escalating environmental challenges posed by waste rubber tyres (WRTs) necessitate innovative solutions to address their detrimental effects on the geoenvironment. Thus, the knowledge about the recent advancements in material recovery from WRTs, emphasising their utilisation within the framework of the United Nations Sustainable Development Goals (SDGs) and the circular economy principles, is the need of the hour. Keeping this in mind, various techniques generally used for material recovery, viz., ambient, cryogenic, waterjet, and so on, which unveil innovative approaches to reclaiming valuable resources (viz., recycled rubber, textiles, steel wires, etc.) from WRTs and various devulcanisation techniques (viz., physical, chemical, and microbial) are elaborated in this paper. In parallel, the paper explores the utilisation of the WRTs and recovered materials, highlighting their application in geotechnical and geoenvironmental engineering development projects while addressing the necessary environmental precautions and associated environmental risks/concerns. This paper incorporates circular economy principles into WRTs utilisation and focuses on achieving SDGs by promoting resource efficiency and minimising their environmental impact.

Accurate continuum modelling of granular flows is essential for predicting geohazards such as flow-like landslides and debris flows. Achieving such precision necessitates both a robust constitutive model for granular media and a numerical solver capable of handling large deformations. In this work, a novel unified phase transition constitutive model for granular media is proposed that follows a generalized Maxwell framework. The stress is divided into an elastoplastic part and a viscous part. The former utilizes a critical-state-based elastoplasticity model, while the latter employs a strain acceleration-based mu(I) rheology model. Key characteristics such as nonlinear elasticity, nonlinear plastic hardening, stress dilatancy, and critical state concept are incorporated into the elastoplasticity model, and the non-Newtonian mu(I) rheology model considers strain rate and strain acceleration (i.e., a higher-order derivative of strain) to capture changes in accelerated and decelerated flow conditions. A series of element tests is simulated using the proposed unified phase transition model, demonstrating that the novel theory effectively describes the transition of granular media from solid-like to fluid-like states in a unified manner. The proposed unified model is then implemented within the material point method (MPM) framework to simulate 2D and 3D granular flows. The results show remarkable consistency with results from experiments and other numerical methods, demonstrating the model's accuracy in capturing solid-like behaviour during inception and deposition, as well as liquid-like behaviour during propagation.

In this paper a three-dimensional agro-hydrological model for shallow landslides' prediction is presented. The model is an extension of the CRITERIA-3D free-source model for crop development and soil hydrology, developed by the Hydrometeorological service of the Regional Agency for Environmental prevention and Energy of EmiliaRomagna region (Arpae-simc). The soil-water balance is computed through the coupling of surface and subsurface flows in multi-layered soils over areas topographically characterized by Digital Elevation Model (DEM). The rainfall infiltration process is simulated through a three-dimensional version of Richards' equation. Surface runoff, lateral drainage, capillarity rise, soil evaporation and plant transpiration contribute to the computation of the soil hydrology on an hourly basis. The model accepts meteorological hourly records as input data and outputs can be obtained for any time step at any selected depth of the soil profile. Among the outputs, volumetric water content, soil-water potential and the factor of safety of the slope can be selected. The validation of the proposed model has been carried out considering a test slope in Montue` (northern Italy), where a shallow landslide occurred in 2014 a few meters away from a meteorological and soil moisture measurement station. The paper shows the accuracy of the model in predicting the landslide occurrence in response to rainfall both in time and space. Although there are some model limitations, at the slope scale the model results are highly accurate with respect to field data even when the spatial resolution of the Digital Elevation Model is reduced.

During the development blasting of circular tunnels, the detonation of multiple blastholes arranged on concentric circles induces a complex dynamic response in the surrounding rocks. This process involves multiple blast loadings, static stress unloadings, and stress redistributions. In this study, the dynamic stresses of the surrounding rocks during development blasting, considering multiple blasting-unloading stages with exponential paths and triangular paths (linear simplified paths of exponential paths), are solved based on the dynamic theory and the Fourier transform method. Then, a corresponding discrete element model is established using particle flow code (PFC). The multiple-stage dynamic stress and fracture distribution under different in situ stress levels and lateral coefficients are investigated. Theoretical results indicate that the peak compressive stresses in the surrounding rocks induced by both triangular and exponential paths are equal, while the triangular path generates greater additional dynamic tensile stresses, particularly in the circumferential direction, compared to the exponential path. Numerical results show that the exponential path causes less dynamic circumferential tensile damage and forms fewer radial fractures than the triangular path in the first few blast stages; conversely, it exacerbates the damage and instability in the final blasting-unloading stage and forms more circumferential fractures. Furthermore, the in situ stress determines which of the two opposite effects is dominant. Therefore, when using overly simplified triangular paths to evaluate the stability of surrounding rocks, potential overestimation or underestimation caused by different failure mechanisms should be considered. Specifically, under high horizontal and vertical stresses, the static stress redistribution with layer-by-layer blasting suppresses dynamic circumferential tensile and radial compressive damage. The damage evolution of surrounding rocks in multi-stage blasting under different in situ stresses is summarized and classified according to the damage mechanism and characteristics, which can guide blasting and support design. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

The K & uuml;& ccedil;& uuml;k & ccedil;ekmece-Avc & imath;lar corridor of the D100 highway constitutes a critical component of Istanbul's transportation infrastructure. Given its strategic importance, ensuring its operational continuity following the anticipated major Istanbul earthquake is imperative. The aim of this study was to investigate the liquefaction-induced geotechnical risks threatening the K & uuml;& ccedil;& uuml;k & ccedil;ekmece-Avc & imath;lar segment of the D100 highway. Initially, the study area's liquefaction susceptibility was assessed through Liquefaction Potential Index mapping. Subsequently, post-liquefaction ground displacements were quantified using semi-empirical methodologies and advanced numerical analyses focused on representative critical sections. Numerical simulations incorporated various constitutive models for liquefiable soils, enabling a comparative assessment against semi-empirical estimations. The results revealed that semi-empirical approaches systematically overestimated the lateral displacements relative to numerical predictions. Moreover, the analyses highlighted the sensitivity of model outcomes to the selection of constitutive parameters, underscoring the necessity for careful calibration in modeling liquefiable layers. Despite considering the most conservative displacement values from numerical analyses, findings indicated that the D100 highway is likely to experience substantial damage, potentially leading to extended service disruptions following the projected seismic event.