The breakage phenomenon has gained attention from geotechnical and mining engineers primarily due to its pivotal influence on the mechanical response of granular soils. Numerous researchers performed laboratory tests on crushable soils and incorporated the corresponding effects into numerical simulations. A systematic review of various studies is crucial for gaining insight into the current state of knowledge and for illuminating the required developments for upcoming research projects. The current state-of-the-art study summarizes both experimental evidence and numerical approaches, particularly focusing on discrete element simulations and constitutive models used to describe the behavior of crushable soils. The review begins by exploring particle breakage quantification, delving into experimental evidence to elucidate its influence on the mechanical behavior of granular soils, and examining the factors that affect the breakage phenomenon. In this context, the accuracy of various indices in estimating the extent of breakage has been assessed through ten series of experiments conducted on different crushable soils. Furthermore, alternative breakage indices are suggested for constitutive models to track the evolution of particle crushing under continuous shearing. Regarding numerical modeling, the review covers different approaches using the discrete element method (DEM) for simulating the behavior of crushable particulate media, discussing the advantages and disadvantages of each approach. Additionally, different families of constitutive models, including elastoplasticity, hypoplasticity, and thermodynamically based approaches, are analyzed. The performance of one model from each group is evaluated in simulating the response of Tacheng rockfill material under drained triaxial tests. Finally, new insights into the development of constitutive models and areas requiring further investigation utilizing DEM have been highlighted.

Debris flows are a dynamic and hazardous geological phenomenon, as by definition, debris flows are rapid, gravity-driven flows of saturated materials that often contain a mixture of water, rock, soil, and organic matter. They are highly destructive and occur in steep channels, posing a significant threat to infrastructure and human life. The dynamics of debris flows are complex due to their non-Newtonian behaviour and varying sediment-water interactions, making accurate modelling essential for risk mitigation and emergency planning. This paper reports and discusses the results of numerical simulations of back analyses aimed at studying the reconstruction of a real rapid debris flow. The selected test case is the event that occurred on 12 and 16 March 2021 along the Rio Sonno channel, a tributary of the Liri River, following the landslide event of Rendinara (Municipality of Morino, Abruzzo Region, Italy). There are significant flow sources in the area, fed by a highly fractured carbonaceous aquifer that extends immediately upslope of the detachment zone. The continuous flow influences the saturation level in the fine-grained sediments and favours the triggering of the debris flow. This phenomenon was simulated using the commercial RAMMS code, and the rheological model selected was Voellmy fluid friction. The modelling approaches used in this research are valid tools to estimate the volumes of materials involved in the flow-feeding process and for the purpose of possible mitigation works (debris flow-type dams, weirs, flow diversion, etc.).

Polymer-blend geocell sheets (PBGS) have been developed as substitute materials for manufacturing geocells. Various attempts have been made to test and predict the behaviors of commonly used geogrids, geotextiles, geomembranes, and geocells. However, the elastic-viscoplastic behaviors of novel-developed geocell sheets are still poorly understood. Therefore, this paper investigates the elastic-viscoplastic behaviors of PBGS to gain a comprehensive understanding of their mechanical properties. Furthermore, the tensile load-strain history under various loading conditions is simulated by numerical calculation for widespread utilization. To achieve this goal, monotonic loading tests, short-term creep and stress relaxation tests, and multi-load-path tests (also known as arbitrary loading history tests) are performed using a universal testing machine. The results are simulated using the nonlinear three-component (NLTC) model, which consists of three nonlinear components, i.e. a hypo-elastic component, a nonlinear inviscid component, and a nonlinear viscid component. The experimental and numerical results demonstrate that PBGS exhibit significant elastic-viscoplastic behavior that can be accurately predicted by the NLTC model. Moreover, the tensile strain rates significantly influence the tensile load, with higher strain rates resulting in increased tensile loads and more linear load-strain curves. Also, parametric analysis of the rheological characteristics reveals that the initial tensile strain rates have negligible impact on the results. The rate-sensitivity coefficient of PBGS is approximately 0.163, which falls within the typical range observed in most geosynthetics. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting 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/).

Burial depth is a crucial factor affecting the forces and deformation of tunnels during earthquakes. One key issue is a lack of understanding of the effect of a change in the buried depth of a single-side tunnel on the seismic response of a double-tunnel system. In this study, shaking table tests were designed and performed based on a tunnel under construction in Dalian, China. Numerical models were established using the equivalent linear method combined with ABAQUS finite element software to analyze the seismic response of the interacting system. The results showed that the amplification coefficient of the soil acceleration did not change evidently with the burial depth of the new tunnel but decreased as the seismic amplitude increased. In addition, the existing tunnel acceleration, earth pressure, and internal force were hardly affected by the change in the burial depth; for the new tunnel, the acceleration and internal force decreased as the burial depth increased, while the earth pressure increased. This shows that the earth pressure distribution in a double-tunnel system is relatively complex and mainly concentrated on the arch spandrel and arch springing of the relative area. Overall, when the horizontal clearance between the center of the two tunnels was more than twice the sum of the radius of the outer edges of the two tunnels, the change in the burial depth of the new tunnel had little effect on the existing one, and the tunnel structure was deemed safe. These results provide a preliminary understanding and reference for the seismic performance of a double-tunnel system.

The pounding between two structures may cause severe damage, as demonstrated during historical seismic events. In particular, the effects of the continuity between the foundations below two structures have been investigated a few times in the past literature. Two different configurations (continue and non -continue foundations) have been investigated herein by considering several low-rise buildings. In order to consider the effects of Soil Structure Interaction (SSI) between the structures, the foundation, and the soil, a deformable soil below the foundations was considered. 3D Numerical simulations have been performed with Opensees by considering the SSI non -linear mechanisms of the complex system: soil-foundation-structure. A parametric study on the dynamic characteristics (fundamental periods) of the two structures was performed in order to assess the mutual effects of the soil and the considered low-rise buildings. It was demonstrated the role of continued foundations, whether for existing or new buildings, on reducing the pounding risk between structures. In particular, the collision between the two foundations may significantly increase the response of the building, depending on its flexibility. Also, the level of stress in the soil depends on the pounding forces causing significant increases in the structural deformations.

With more and more the transportation tunnels that have been and will be constructed in loess areas in Northwest China with high earthquake potential, the overall stability of tunnel portal sections under earthquake action and the related aseismic countermeasures has attracted the attention of both scholars and engineers, especially for tunnels in upper slope connecting high bridges crossing rivers or valleys. To study the dynamic response characteristics and damage evolution of steep loess slopes with tunnels under earthquake action, large-scale shaking table tests and numerical simulations were performed on steep loess slopes with tunnels. In particular, three-dimensional noncontact optical measurement techniques were used to obtain the slope surface displacements. The results showed that the main deformation patterns of the studied slopes were horizontal movement and settlement when the seismic waves were input in the X and X-Z directions, respectively. However, the seismic wave from the X direction had a greater impact on the deformation of a slope than that from the X-Z direction, and the tunnel portal slopes were ultimately destroyed under the action of a large horizontal seismic acceleration. Slope failure ahead of a tunnel was divided into four stages, i.e., the elastic deformation stage, plastic deformation accumulation stage, local failure stage, and overall failure stage. The existence of the tunnel had a great influence on the peak ground acceleration (PGA) and the PGA amplification factor (PGAAF) of the surrounding soil mass. The changes in the PGD and PGA on the slope surface determined via numerical simulation were basically consistent with the experimental results.

Owing to valuable significance of bioconvective transport phenomenon in interaction of nanoparticles, different applications are suggested in field of bio-technology, bio-fuels, fertilizers and soil sciences. It is well emphasized fact that thermal outcomes of nanofluids can be boosted under the consideration of various thermal sources. The aim of current research is to test the induction of induced magnetic force in bioconvective transport of non-Newtonian nanofluid. The rheological impact of non-Newtonian materials is observed by using Casson fluid with suspension of microorganisms. The chemical reaction effected are interpreted. The thermal conductivity of material is assumed to be fluctuated with temperature fluctuation. The flow pattern is endorsed by stretching surface following the stagnation point flow. Under the defined flow assumptions, the problem is formulated. A computational software with shooting technique is used to present the simulations. A comprehensive analysis for problem is presented. It is claimed that the interpretation of induced magnetic force exclusively enhanced the thermal phenomenon.

Thermal conduction control is important for retarding permafrost degradation and mitigating of frost geohazards. Similar to a thermodiode, high thermal conductivity contrast (HTCC) materials can serve as good thermal insulators. A preferred HTCC material for ground cooling is larger in thermal resistance in summer and smaller in winter. Because of contrasting thermal conductivity under frozen and thawed states, organic soil is blessed with such a property. This study quantified and reported the HTCC effects on a range of soil organic matter concentrations (SOMC) and soil moisture saturation degree (SMSD). Using the COMSOL, influences of different SOMC and SMSD on ground temperatures were simulated and compared with laboratory-measured properties. Simulation results demonstrated that with constant SMSD at 20% throughout the year, the thermal insulation effect was strengthened with increasing SOMC. A better insulating effect was judged by lower annual amplitudes and smaller depths of zero annual amplitude of ground temperatures. In case of low SMSD in summer (20%) and high SMSD in winter (60-80%), the HTCC effect of soil is enhanced with increasing SOMC. This enhancement was evidenced by increased thermal offsets and decreased maximum summer and average nearsurface soil temperatures. With constant SOMC and increasing SMSD, the rising HTCC effect gradually cools the ground. An integral analysis indicates that the higher the SOMC and SMSD in winter, the larger the thermal offset and the lower the ground temperature, i.e., the greater the HTCC effect of organic soil. This study may provide geocryological bases for engineering and environmental applications in cold regions.