Performance of pile foundations is significantly influenced by the micromechanical behaviour of the pile-soil interface. In frozen ground, the interface behaviour is temperature-dependent and viscous. This study examines the pullout behaviour of a single pile embedded in frozen soil using a two-dimensional axisymmetric finite element model developed with Abaqus software. A cohesive zone model (CZM) is employed along with a penalty type contact interaction to represent the interface behaviour while a time-hardening power-law creep model is used to simulate the viscous response of the interaction. The model is coupled with temperature and verified by data from temperature-controlled laboratory pullout and creep tests of model pile in frozen sand. The findings demonstrated that CZM effectively describes the behaviour of the frozen interface. Conceptual models that account for non-uniform temperature profiles and variable temperature time-series, showcase the significant influence of temperature on the overall performance of pile foundations in cold regions.

Wear of tillage tools by hard soil particles is a serious concern in the industry since wear is the primary factor that defines an engaging tool's lifespan, stability, and reliability. Many studies have primarily focused on experimental methods to better understand the impact of various parameters on tool wear during tilling operations. Hence, this project focuses on both continuum damage mechanics (CDM) modesl based on thermodynamics for predicting the wear coefficient in tillage tools and experimental validation. The wear process is modeled as sand particle scratching at a prescribed speed and load on the surface of a tillage tool with different hardness, such as heat treated, chromium coated, heat-treated chromium coated, and samples without any treatment. Tillage tool wear is taken as the response (output) variable measured during contact, while operation parameters speed, load, and hardness are taken as input parameters. For C45E4 samples, tests are carried out with a dry sand/rubber wheel abrasion tester, and material loss from the tool surface during scratching is evaluated using the weight loss concept. The design of experiments technique is developed for three factors at four levels. The comparison shows an acceptable agreement in the experimental data and predicted results, which states an error of <20 %. The results also show that heat-treated samples with chromium coating have more abrasive resistance with respect to other samples.

During drilling operations, cyclic loading is exerted on the wellbore wall by the vibrations of the drill string. This loading could lead to rock fatigue, which in turn might result in wellbore failure. In this study, numerical model is developed to simulate the effects of repeated loading on rock fatigue and failure. The simulation is based on an elasto-plastic constitutive model coupled with a damage mechanics approach, which allows us to examine the wellbore instability due to drill string vibrations. The model is verified with the existing data in the literature related to experiments on impact of a steel ball against a curved wall. The findings indicate that cyclic loading increases the development of plastic strain around the wellbore significantly compared to static conditions, promoting rock fatigue. Furthermore, the cyclic loading expands the radius of the yielded zone substantially, a critical factor for maintaining wellbore integrity. The proposed model can be used to evaluate the wellbore stability under repetitive loading caused by the drill string action. 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

The establishment of mechanical models of rocks can provide crucial guidance to the surrounding rocks stability analysis in the rock engineering. According to statistical damage theory and Mohr-Coulomb strength criterion, the Logistic model is used to yield the damage evolution equation and further establish statistical damage constitutive model for describing the whole failure process of rocks. Then, the rationality of the proposed damage model is proved by comparing with the different test curves, and damage evolution laws are summarized into four stages, including: slow-growth stage, rapid-growth stage, constant-speed-similar growth stage and speed-reducing growth stage. Physical meanings of model parameters r' and m are also discussed. Finally, to verify the application of this proposed model, this damage constitutive model is developed and implemented to simulate the tunnel excavation and analyze the stability of surrounding rocks by using Fortran, python and Abaqus. The displacement data on site is used to prove the superiority of proposed damage constitutive model compared with the existing ones in Abaqus. The research outcomes presented in this paper can also provide useful references for the theory and application of rock mechanics.

Soil constitutive models are widely investigated and applied in soil mechanical behaviors simulation; however, the damage evolution process of soil with various shear deformation behaviors was rarely studied. This study introduces a novel shear constitutive model for slip zone soil considering its damage evolution process. Firstly, an innovative method for determining the shear stiffness is proposed to assess the damage degree of slip zone soil during shear deformation. Further, a damage evolution model based on the log-logistic function is derived to characterize the damage evolution process of slip zone soil, and a new shear constitutive model based on the damage evolution process is subsequently proposed. Both the damage evolution model and the shear constitutive model are verified by the ring shear test data of the slip zone soil from the Outang landslide in the Three Gorges Reservoir area of China. Compared to the traditional peak-solving constitutive model based on the Weibull distribution, the proposed shear constitutive model has the distinct advantage of describing not only the brittle (strain softening) mechanical behavior but also the ductile and plastic hardening mechanical behavior of soil. In summary, this method offers a rapid determination of the damage evolution process and the shear behavior constitutive relationship of slip zone soil in landslides.

Tunnels offer myriad benefits for modern countries, and understanding their behavior under loads is critical. This paper analyzes and evaluates the damage to buried horseshoe tunnels under soil pressure and traffic loading. To achieve this, a numerical model of this type of tunnel is first created using ABAQUS software. Then, fracture mechanics theory is applied to investigate the fracture and damage of the horseshoe tunnel. The numerical analysis is based on the damage plasticity model of concrete, which describes the inelastic behavior of concrete in tension and compression. In addition, the reinforcing steel is modeled using the bilinear plasticity model. Damage contours, stress contours, and maximum displacements illustrate how and where traffic loading alters the response of the horseshoe tunnel. Based on the results, the fracture mechanism proceeded as follows: initially, damage started at the center of the tunnel bottom, followed by the formation of damage and micro-cracks at the corners of the tunnel. Eventually, the damage reached the top of the concrete arch with increasing loading. Therefore, in the design of this tunnel, these critical areas should be reinforced more to prevent cracking.

For evaluating the post-earthquake failure probability of the immersed tunnel of Hong Kong-Zhuhai-Macao Bridge subjected transverse earthquake loading. A two-dimensional (2-D) finite element model considering the water-soil-tunnel interaction has been built based on the Abaqus software platform, and a more refined threedimensional(3-D) model was built to examine the preciseness of the 2-D model in calculating the displacement response of immersed tunnel. The seismic damage evaluation of immersed tunnel was presented based the numerical analysis results of 3-D model, and it indicated the IDR is significant related to the damage level of tunnel. The inter-story drift ratio limits of immersed tunnel were defined based on the seismic performance curve obtained from the Pushover analysis. The non-linear dynamic analysis was performed for the 2-D model subjected different amplitude-modulated earthquake records according to the incremental dynamical analysis (IDA) procedure. The IDA curve cluster and corresponding 16 %, 50 %, 84 % percentile lines were plotted by defining the damage measure as the inter-story drift ratio, and employing the PGA to describe the intensity measures. The probability of the immersed tunnel exceeding different seismic performance level subjected different earthquake intensity have been given, and the finding shown the immersed tunnel perform enjoying good seismic performance.