The issue of problematic disposal of excavated material, commonly referred to as muck, generated during tunnel boring machine (TBM) excavation has emerged as an environmental challenge amidst the escalating demand for sustainable engineering solutions. TBM excavation operations necessitate the use of a slurry to bolster the excavation process and aid in muck conveyance. Typically composed of bentonite, this TBM slurry is conventionally discarded along with the excavated spoils, posing risks to human safety and raising environmental contamination apprehensions. This study aims to explore a novel slurry material as a means to mitigate the toxicity associated with muck disposal. Given the notable adsorption capabilities of bentonite, alternative options such as kaolinite clay and xanthan gum biopolymer are under consideration. Through experimental analysis, various combinations of bentonite clay, kaolinite clay, and xanthan gum are examined to assess their effectiveness in enhancing tunneling performance and optimizing transport properties. The evaluated parameters encompass rheological characteristics, swelling behavior, permeability, suspended viscosity and stickiness. Employing statistical analysis integrated with random weighting factors and the measured properties of each slurry candidate, competitiveness of each slurry candidate is analyzed. The findings of this investigation, accounting for 47.31% priority across all probabilistic scenarios, indicate that a specific blend consisting of bentonite and xanthan gum (2.5% bentonite, 0.75% xanthan gum) demonstrates considerable promise as a substitute for conventional bentonite-based slurries (7.5% bentonite) in TBM excavation applications.

The aim of the present investigation is focused on the nonlinear forced vibration analysis of porous FGM sandwich beam with a viscoelastic core resting on nonlinear elastic foundation. The analytical formulation incorporates both normal and shear deformations in the core by utilizing the Zig-Zag theories. The harmonic balance method is integrated with a one-mode Galerkin's procedure designed for a simply supported beam. The nonlinear geometric coupling and viscoelastic effects result in a frequency amplitude equation that is nonlinear and governed by multiple complex coefficients. The damping and frequency response curves are depicted and analyzed across various geometrical and mechanical configurations of sandwich beams. The results indicate that the porosity effects and elastic coefficients of the foundation exert a significant influence on the damping and nonlinear vibration response of these beams.

The pressurized water conditions of goafs weaken the support of remaining coal and rocks, which causes instability, failure, and sudden ground collapse. The impact of pressure-bearing water and CO₂ on the tensile properties of residual coal pillars was explored in old goafs. Coal was analyzed using a pressure-water soaking device, electronic scanning microscope, and 3D full-field strain measurement system. Besides, Brazilian splitting tests were performed. The failure characteristics and energy evolution law of the macro-microscopic structure of coal specimens were analyzed under different soaking conditions-desiccation (DC), CO₂ soaking (CS), water-CO₂ soaking (WCS), and water soaking (WS). The peak stress of coal specimens and time to reach the peak decreased with varying soaking environments. Stress concentration initially occurred at the water end under the WCS condition, indicating that coal specimens deteriorated more under the pressure-bearing WCS condition compared with the CS condition. Fractures of coal specimens exhibited the highest development under the WS condition. Besides, dissolution was observed at the fractures of coal specimens, with severe failure to their internal microstructures. In conclusion, the instability failure of residual coal pillars is significant in studying the old goafs.

The construction of the shield tunnel results in the deformation of the surrounding soil and the existing pipeline. It is important to analyze the deformation of the existing pipeline during the excavation of the tunnel. Based on the two-stage analysis method, the shear effect of pipeline due to the uneven settlement was considered and the deformation and internal force of existing pipeline due to the tunnel excavation were studied. The theoretical formulas were verified by the in-site monitoring. Compared with the theoretical calculation, the three-dimensional numerical simulation was established to simulate the deformation of the existing pipeline and the ground surface during the tunnelling. The effect of the Poisson's ratio, the tunnel diameter and the pipeline shading on the deformation of the existing pipeline were further investigated. The results show that the deformation curves of the pipeline and the ground surface conform to the Gaussian distribution, and the position above the axis of the tunnel experiences the maximum. When the excavation surface of tunnel crosses underneath the pipeline, the pipeline and the ground surface experience larger deformation and more subsidence, respectively. A certain amount of uplift is generated for the pipeline and the ground surface at ± 20 m away from the center line of the tunnel. The deformation of existing pipelines is affected by the tunnel excavation within its diameter range. The results can provide a reference for the design and construction of the shield tunnel underpass.

With the recent development of satellite, aerial, and remote sensing technologies, it is easy to produce landslide inventory maps over a large area. In this study, the object-based framework was designed to address the limitations inherent in the pixel-based deep learning (DL) methodology. This framework explores the potential of combining Sentinel-2 MultiSpectral Instrument (MSI) satellite imagery and digital elevation models (DEMs) to enhance shallow landslide mapping across diverse terrains comprehensively. The study area for analysis and verification was selected as Jucheon-myeon, Namwon-si, and Jeollabuk-do, where significant large-scale landslides and slope failures occurred in 2020. As a result, the application of this framework led to the classification of 68 candidate sites spanning an area of 0.5 hectares or more. Site surveying was conducted on 20 random sites with a 1ha or more scale. Furthermore, six sites were selected where satellite imagery could discern the damaged areas. At these locations, the damaged area estimated by the framework was compared with the actual observed damaged area to assess accuracy. These rapid and cost-effective landslide mapping techniques can accurately estimate the location and extent of landslides and enhance the precision of sensitivity models and land management strategies.

The goal of this work is to examine how a fiber-reinforced thermoelastic half-space with voids is affected by the gravity field and viscosity. The displacement, stress, and temperature distributions' analytical formulas are obtained from the normal mode analysis. The problem is analytically addressed using a three-phase-lag model. Use MATLAB programming to determine the physical fields with appropriate boundary conditions and carry out numerical computations. Examine the outcomes in the absence and presence of gravity, viscosity as well as reinforcement. Graphs are used to visualize and analyze computational findings. Theoretical as well as numerical results reveal that all the field variables are sensitive towards the gravity field, the viscosity, and the reinforcement.

Construction on waterlogged ground presents significant challenges for geotechnical engineers due to the low bearing capacity, high water table, and risks of post-construction settlement, all of which can compromise the stability of buildings. This study aims to investigate the settlement behavior of foundations on such terrains and recommend suitable foundation types to safely support building loads. To achieve these objectives, three-dimensional coupled consolidation analyses were performed to evaluate the bearing capacities of shallow footings with dimensions of 1.22 × 1.22 m² and 1.83 × 1.83 m². The results showed ultimate load capacities of approximately 10 kN and 21 kN, respectively, for these footings on waterlogged ground. To enhance these capacities, the use of pit sand as a filling material was explored, yielding substantial improvements. The bearing capacity of the 1.22 × 1.22 m² footing increased by a factor of 9, while the 1.83 × 1.83 m² footing saw a sixfold improvement. In addition, alternative foundation solutions were evaluated to achieve higher load-bearing capacities. These included raft foundations, single piles, pile groups, and piled raft foundations. Among these, a single pile demonstrated an ultimate load capacity of 300 kN, while a (2 × 2) pile group supported up to 400 kN. The piled raft foundation exhibited the highest capacity, with an ultimate load of 620 kN. These findings provide valuable insights into effective foundation designs for waterlogged conditions, enabling safer and more reliable construction practices.