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The freezing damage of rock tunnels in cold region involves ice-water phase change and complicated interaction of Thermo–Hydro–Mechanical (THM) field. Taking the fractured rock mass of cold region tunnels as research subject, the THM coupling model of cold region tunnels was established, which is based on the seepage mechanics, heat transfer theory, damage mechanics and equivalent continuum theory. This model could reflect the anisotropic properties of deformation, water migration and heat transfer caused by the initial fracture of rock mass. The construction and operation processes of a rock tunnel in cold region were simulated, and results were compared with the measured value and predecessor’s achievements. It shows that proposed model could reflect the anisotropic property of surrounding rock and the simulated deformation and stress are not symmetrical. Compared with the literature, the calculated results in this paper are closer to the measured values. The insulating layer has a significant effect on the stress of the supporting structures. The maximum tension stress of the lining is 4.5 times as that without insulating layer, and the lining will be destroyed for the overlarge tension stress.

During the construction of mountain tunnels, there are often various intricate and mutable potential hazards, the management and control of which are crucial to ensuring the safety of such construction. With the rapid advancement of engineering information technologies, including Building Information Model (BIM), the internet, big data, and cloud computing, dynamic management of mountain tunnel construction will inevitably become a prevailing trend. This paper proposes a new digital approach to realize the informatization and visualization of risk management in mountain tunnel construction, by combining monitoring measurement with advanced geological prediction based on BIM technology. The proposed approach suggests a BIM-based digital platform architecture for mountain tunnel construction, which is comprised of five layers—basic, model, data, application, and user. The integration of these five layers can realize risk management information during the construction of mountain tunnels. In addition, a set of dynamic risk management systems, including risk monitoring, identification, and assessment, can be established based on the digital platform. The digital platform and dynamic risk management system proposed in this paper have certain advantages in the construction of mountain tunnels, providing a new and significant way for the management of safety risks in such construction projects.

Freeze–thaw failure of frozen rock slope often occurs during engineering construction and mining in cold area, which poses a great threat to engineering construction and people's life safety. The properties of rock mass in cold region will change with the periodic change of temperature, which makes it difficult to accurately evaluate the stability of slope under the action of freeze–thaw cycle by conventional methods. Based on field investigation and literature review, this paper discusses the characteristics of frozen rock mass and the failure mechanism of frozen rock slope, and gives the types and failure modes of frozen rock slope. Then, the research status of frozen rock slope is analyzed. It is pointed out that the failure of frozen rock slope is the result of thermo-hydro-mechanical (THM) coupling. It is considered that freeze–thaw cycle, rainfall infiltration and fracture propagation have significant effects on the stability of frozen rock slope, and numerical simulation is used to demonstrate. The research shows that the safety factor of frozen rock slope changes dynamically with the surface temperature, and the safety factor of slope decreases year by year with the increase of freeze–thaw cycles, and the fracture expansion will significantly reduce the safety factor. Based on the above knowledge, a time-varying evaluation method of frozen rock slope stability based on THM coupling theory is proposed. This paper can deepen scholars' understanding of rock fracture slope in cold area and promote related research work.

A large amount of lining cracks, pavement uplift and cable trench overturning occurred during the operation of the Dugongling tunnel, which finally led to the closure of the whole line. The study on the lining cracking mechanism is very important to ensure that the tunnel opens again early. First, the actual cracks of the lining were investigated in the field. According to the geological data, the expansion and softening of the surrounding rock is likely to be the main cause of lining cracking. To verify this inference, a corresponding research program was drawn up. Then, representative sections were selected and the back-analysis method was used to simulate the cracking characteristics of the lining. Based on the simulation results, the cracking mechanisms were studied. The research showed that the increased water content caused the expansion and softening of the surrounding rock, increased the uneven loading on the lining structure, and, finally, led to lining cracking and pavement uplift. Based on the cracking mechanism, progressive enhancement schemes were proposed for each section. The research results of this paper can provide a reference for the design and construction of this project and similar projects.

The renewal of traditional villages should not only focus on the protection of cultural heritage but also comprehensively consider the development of social, economic, and environmental aspects. The concept of place-making offers an effective strategy to address the issues faced by traditional villages today, such as the destruction of cultural heritage, socioeconomic decline, and population loss. At the core of place-making is the establishment of harmonious human–land relationships. This study aims to explore the influence of different entities on place-making during the process of traditional village renewal. This research focused on traditional villages in southeastern China. Based on literature reviews and field surveys, this study employed the analytic hierarchy process (AHP) to develop evaluation criteria for traditional village renewal based on place-making. By selecting case studies of traditional village renewal driven by three entities, government, artists, and villagers, relevant data were collected through field surveys and expert assessments, followed by a comparative analysis of these villages using the place-making evaluation criteria. The results indicate significant differences in traditional village renewal due to varying entity-driven approaches, leading to diverse impacts on different facets of place-making. In conclusion, establishing a renewal model for traditional villages that involves diverse entities is crucial for achieving comprehensive place-making and ensuring the high-quality, integrated, and sustainable development of traditional villages.

Rural house is a fundamental component of rural settlements, and understanding its construction and development characteristics is crucial for rural land use and development planning. This paper focuses on the spatiotemporal characteristics and influencing factors of Rural Houses Construction Development (RHCD) from 1980 to 2019 with a case study of Qingyuan Town in China. Based on the literature review and filed research, a set of evaluation indicators for RHCD was established. The article calculates RHCD indicators from temporal and spatial dimensions, uses the location entropy method to demonstrate the spatial distribution of indicators, and classifies the RHCD type of 14 villages in Qingyuan Town using clustering algorithms. It also analyzes the influencing factors of spatiotemporal distribution. The results show that the RHCD in Qingyuan Town exhibits typical characteristics of mountainous areas and aligns with the development trends of rural society in China. Population growth, geographical location, and economic development are the primary driving factors for the quantity indicator (Qi), while economic growth, construction technology, industrial development, and policy adjustments are the key factors influencing the form indicator (Fi). In future policy-making, greater emphasis should be placed on optimizing development strategies, improving data and monitoring systems, and integrating administrative strength with actual development needs.

Many underground projects are built in cohesionless soil regions, where soil strength is crucial for stability. Particle size greatly influences the mechanical behavior of cohesionless soil. To investigate the relationship between particle size (as a single internal variable) and the strength behavior of cohesionless soil, this study employed idealized spherical glass beads of varying sizes as an experimental material. A series of consolidated-drained triaxial compression tests, including both conventional and large-scale tests, were conducted on specimens with different particle sizes. The correlation between particle size and stress-strain behavior, as well as strength characteristics, was analyzed. Additionally, the influence of particle size variations on the macroscopic strength characteristics was investigated. Results indicated that for both small-sized (2 mm–6 mm) or large-sized (10 mm–30 mm) granular materials, the peak shear stress and internal friction angle increased with increased particle size. The strength of large-sized granular materials was significantly higher than that of small-sized ones. During the shear process of large-sized particles, the particle breakage rate initially increased and then decreased with increasing particle size. The internal friction angle rose monotonically with particle size, but showed insensitivity in the 4 mm–5 mm and 20 mm–25 mm particle size ranges. This insensitivity reflects a macroscopic effect resulting from the interplay between the number of inter-particle contacts and the micro-area of their surface, which reaches an extremum. These findings provide valuable insights into the micromechanical interactions governing the strength of behavior of cohesionless soils and highlight the importance considering particle size effects in geotechnical analysis. The derived particle-interaction framework provides theoretical underpinnings for optimizing design methodologies in underground infrastructure projects involving granular media.

To analytically describe the internal stress in a fill mass made of granular man-made material (cemented paste backfill, CPB), a new 3D effective stress model is developed. The developed model integrates Bishop effective stress principle, water retention relationship, and arching effect. All model parameters are determined from measurable experimental data. The uncertainties of the model parameters are examined by sensitivity analysis. A series of model application is conducted to investigate the effects of field conditions on the internal stress in CPB. The obtained results show that the proposed model is able to capture the influence of operation time, stope geometry, and rock/CPB interface properties on the effective stress in CPB. Hence, the developed model can be used as a useful tool for the optimal design of CPB structure.

Reasonable excavation step footage and lining support timing are highly important for improving tunnel construction efficiency and ensuring construction safety. Taking the Huanxian No. 1 Tunnel of the Xi-Yin railway as the basis of this study, a 3D numerical model was established using MIDAS GTS NX290 finite element software. This model was used to investigate the deformation and force characteristics of the tunnel-surrounding rock and support structures under three different excavation footages and four different lining construction timings; the numerical results were then compared with the on-site monitoring results. This research aimed to determine reasonable excavation parameters for the three-bench seven-step excavation method used in shallowly buried loess tunnels. The results revealed positive correlations between the excavation step footage and surface subsidence, crown subsidence, and clearance convergence. An excavation footage of 3 m could balance construction efficiency and safety effectively. Keeping the secondary lining construction time unchanged, the early closure of the initial support was beneficial for reducing the force on the secondary lining. Keeping the early closure time of the initial support unchanged, the early construction of the secondary lining would lead to an increase in the force on the secondary lining. The initial support of the tunnel is recommended to be closed as early as possible, and the construction of the secondary lining should be shifted by 21 m behind the upper step palm surface. By comparing the on-site monitoring data with the numerical simulation results, similar trends were observed, providing reference and guidance for the subsequent construction of large-section tunnels in shallowly buried loess formations.

The stability of the two-layer undrained clay slopes should be given considerable attention since they are commonly observed in nature and in manmade structures, and they traditionally have low stability. Therefore, with the elastoplastic finite element method, this paper thoroughly explores the influence of the soil strength parameter cu, slope angle β, and slope depth ratio DH on the slope stability and failure mechanisms by the wide-ranging parametric changes. The aims of this study are also to find the critical strength ratio (cu2/cu1)crit and the maximum values of the stability number Nc that were observed in the parametric studies. Numerical results are displayed in the form of charts to give Nc and (cu2/cu1)crit as a function of cu, β, and DH. Moreover, influences of DH and β on Nc and failure mechanisms are examined in this study. The results of numerical analysis demonstrate that cu2/cu1 significantly affects both the critical failure mechanism and the stability of the two-layer undrained slope. Improved knowledge of the location of the critical failure mechanism allows for accurately estimating the stability of the two-layer undrained slopes for future strengthening measurements to preserve stability.