This study investigates slope stability under rainfall infiltration using numerical modeling in Plaxis 2D, comparing poorly graded sand (6.5% fines) and well-graded sand (11.9% fines) under high-intensity rainfall of 30 mm/h for durations of 8, 12, 18, and 24 h. The results indicate that, as rainfall duration increases, soil saturation rises, leading to reduced suction, lower shear strength, and decreased safety factors (S.F.s). Poorly graded sand shows minimal sensitivity to infiltration, with the S.F. dropping by only 4.3% after 24 h, maintaining values close to the initial 1.126. Conversely, well-graded sand demonstrates significant sensitivity, with its S.F. decreasing by 25.4% after 8 h and 73.7% after 24 h, due to higher water retention capacity and suction. This highlights the significant contrast in stability behavior between the two soil types. The findings emphasize the critical role of soil hydro-mechanical properties in assessing slope stability, especially in regions with intense rainfall. This study establishes a methodology for correlating safety factor variations with rainfall duration and soil type, offering valuable insights for modeling and mitigating landslide risks in rainy climates, considering the hydraulic and mechanical parameters of the soil.

Deep foundation pits, pipe gallery troughs, culverts, and other infrastructure often require backfilling operations. Soil-based controlled low-strength material (soil-based CLSM), with its advantages of self-compaction, self-leveling, and self-hardening, has garnered significant attention in recent years and shows potential as a replacement for traditional rolling compaction backfill materials. Based on the backfill project of the pipe gallery at the Xihong Bridge in Ningbo, this study investigates the unconfined compressive strength, permeability coefficient, compression characteristics, and flow behavior of soil-based CLSM with varying curing agent ratios, assessing its engineering feasibility through field testing. The results demonstrate that soil-based CLSM, particularly with polycarboxylate superplasticizer agent, exhibits substantially improved strength, permeability, construction workability, and other service performance. Additionally, a detailed simulation of the entire pipe gallery foundation pit construction process-including pipe gallery construction, trench backfilling, support removal, and road construction-was performed using the Hardening soil with small strain stiffness model of the soil. The deformation characteristics were analyzed under different backfill conditions to assess the suitability of soil-based CLSM for trench backfilling. The analysis also considered soil deformation under varying curing ages and upper load conditions. The optimized backfilling solution for soil-based CLSM was obtained and validated with field test data. The findings suggest that using soil-based CLSM for foundation trench backfilling can effectively mitigate settlement issues.

The geotechnical properties of soil are crucial in determining the stability of foundations and construction safety in regions with high groundwater levels, such as Warsak Road in Peshawar, Pakistan. Due to its proximity to the Warsak Dam and intersecting irrigation canals, the area experiences a consistently high water table, which significantly impacts soil stability, leading to potential issues such as excessive settlement, reduced shear strength, and increased structural instability. These groundwater conditions pose unique challenges for foundation stability, making it essential to develop a comprehensive understanding of the soil's consolidation behavior and shear strength properties. To address these concerns, this study employs a combined experimental and numerical approach, aiming to evaluate these critical soil properties in detail. The experimental phase involved collecting three undisturbed soil samples from each of the five distinct sites along Warsak Road, spaced approximately 5 km apart. These samples were subjected to standardized laboratory tests, including grain size distribution, specific gravity, Atterberg Limits, direct shear, unconfined compression, and oedometer tests, per ASTM standards. To further validate the laboratory findings, numerical analysis using PLAXIS software was conducted, along with analytical evaluations using the Meyerhof and Vesic bearing capacity equations. This integrated methodology provided a comprehensive understanding of the soil's behavior under varying conditions, revealing distinct variations in the average values of the three samples from each site. Specifically, Site 1 exhibited an average cohesion of 18.22 kN/m2, making it suitable for low-rise structures, whereas Site 2, with an average cohesion of 15.23 kN/m2, indicated the need for stabilization due to its high consolidation potential. Site 3, averaging 13.3 kN/m2, showed higher settlement risk, necessitating deep foundations, while Site 4, with the lowest average cohesion of 9.94 kN/m2, was deemed unsuitable for heavy loads without reinforcement. In contrast, Site 5, having the highest average cohesion of 20.2 kN/m2, demonstrated excellent stability, ideal for multi-story buildings and other heavy structures. The numerical results from PLAXIS offered a more accurate understanding of soil behavior compared to the traditional Meyerhof and Vesic methods, highlighting the necessity of integrating advanced numerical techniques with conventional approaches. Accordingly, targeted soil improvement measures are recommended for weak and highly compressible soils to ensure the long-term stability and safety of structures in the region.

Purpose - The purpose of this paper is the dynamic analysis and seismic damage assessment of steel sheet pile quay wall with inelastic behavior underground motions using several accelerograms. Design/methodology/approach - Finite element analysis is conducted using the Plaxis 2D software to generate the numerical model of quay wall. The extension of berth 25 at the port of Bejaia, located in northeastern Algeria, represents a case study. Incremental dynamic analyses are carried out to examine variation of the main response parameters under seismic excitations with increasing Peak ground acceleration (PGA) levels. Two global damage indices based on the safety factor and bending moment are introduced to assess the relationship between PGA and the damage levels. Findings - The results obtained indicate that the sheet pile quay wall can safely withstand seismic loads up to PGAs of 0.35 g and that above 0.45 g, care should be taken with the risk of reaching the ultimate moment capacity of the steel sheet pile. However, for PGAs greater than 0.5 g, it was clearly demonstrated that the excessive deformations with material are likely to occur in the soil layers and in the structural elements. Originality/value - The main contribution of the present work is a new double seismic damage index for a steel sheet pile supported quay wharf. The numerical modeling is first validated in the static case. Then, the results obtained by performing several incremental dynamic analyses are exploited to evaluate the degradation of the soil safety factor and the seismic capacity of the pile sheet wall. Computed values of the proposed damage indices of the considered quay wharf are a practical helping tool for decision-making regarding the seismic safety of the structure.

Recent accidents in water supply networks have the negative impact on the state of the historical and architectural heritage of the Kyiv-Pechersk Lavra, which has been formed over many centuries and is a UNESCO World Heritage Site. We have analysed the water supply system emergency situation on the territory of the Metropolitan Garden that occurred in October 2022 during the Russian military aggression. It caused surface sinkholes, increased groundwater levels, and significant destruction of a historical underground - the Metropolitan Cellar. The study was carried out using numerical analysis implemented in Plaxis 2D. To resolve the uncertainties of the accident, several options for developing the emergency situation were considered, taking into account the number of probable pipe leakages, their size, etc. Accident parameterization was performed with a leakage volume of 1600.0 m3/day, considering damage to the water supply network in two locations. The volume of the watered soil mass was 7.0-8.5 thousand m3. We evaluated the state of destruction of the southern and southeastern branches of the Metropolitan Cellar. Engineering measures for strengthening the of the Monastery walls with buttress elements, increasing the width of the foundations by means of additional concrete and piling are studied. The numerical calculations were verified using the results of geophysical surveys. Comparison of analytical calculations, geophysical surveys and field surveys showed that parts of the underground structure were completely destroyed. Their restoration is possible only by modern methods through reconstruction, that will lead to a loss of authenticity, which is unacceptable for historical structures. To take preventive actions for the protection of monuments, it is necessary to conduct continuous monitoring.

Tunnels located in liquefiable soils are prone to flotation following earthquakes. When the shaking-induced pore water pressure buildup continues, saturated soil surrounding the tunnels liquefies, flotation occurs and the soil loses its shear resistance against the uplift force from the buoyancy of the tunnel. Mitigation of liquefaction-induced uplift of tunnels is one of the concerns of geotechnical engineers. This article aims to investigate the efficacy of the available mitigation techniques using a finite element program with an emphasis on the prediction of excess pore water pressures in the surrounding soil and the uplift of the tunnel. In addition to the conventional techniques, a newly developed technique Partial Saturation was modeled to examine its effect on the reduction of the tunnel uplift. A parametric study was done to compare the effectiveness of partial saturation with other mitigation techniques. Results showed that the partial saturation technique would effectively dissipate the excess pore water pressure in the soil around the tunnels. It also performs well in the reduction of the uplift of the tunnel. The most appealing advantage of this technique against the other available mitigation techniques is that it can be employed easily without disturbing the soil around the tunnels. A new methodology to numerically simulate the partially saturated sands was described in this paper.

The stone column encasement is a widespread ground improvement technique that effectively improves the engineering characteristics of weak and compressible soils with excessive settlement problems under vertical loadings. Despite the extensive use of stone columns, the settlement response of sandy soils reinforced with various geosynthetic encasement configurations under cyclic loading conditions remains unexplored. This study aimed to understand the settlement response of sandy soils reinforced with dual-layer geosynthetic-encased stone columns (DLGESCs), single-layer geosynthetic-encased stone columns (SLGESCs), and ordinary stone columns (OSCs) under cyclic loading conditions. The effects of cyclic loading amplitude, frequency, and geosynthetic encasement on settlement behavior were investigated using PLAXIS-3D (version 21) software with the hardening soil small constitutive model, and geosynthetic encasements with variable axial stiffness and tensile strength were studied. The study results indicated that higher cyclic loading amplitudes and frequencies increase the settlement of the stone column. DLGESC outperformed SLGESC with a 5.8%-11.2% settlement reduction, while SLGESC reduced settlement by 40.9%-47.8% compared to OSC. Geosynthetic GT3 (800 kN/m axial stiffness, 70 kN/m tensile strength) decreased settlement by 7.6%-13.6% compared to GT1. This research emphasizes ground improvement techniques and demonstrates the way DLGESC reduces settlement and improves structure stability on stone column-reinforced sandy soils. This study can help design resilient and stable foundations for pavements, railroad tracks, and offshore structures under cyclic vertical loading characteristics and suitable encasement configurations.

Environmental vibrations produced often by industrial and construction processes can affect adjacent soils and structures, sometimes resulting in foundation failure and structural damage. The application of confined cells under foundations as a mitigation technique against dynamic sources, such as generators, is investigated in this study. Numerical models were developed using Plaxis 3D software to simulate the effect of a vibrating source on a circular footing, both with and without confined cells filled with sand soil at varying depths and diameters. In these cells, the soil modeling considered compaction loads typical in actual construction conditions. Results indicate that placing a minimum-diameter cell closer to the foundation with adequate penetration depth can significantly enhance dynamic response and reduce subgrade deformation. The effectiveness of confined soil in minimizing displacement amplitude in the foundation is evaluated, revealing an impressive 86% reduction with specific cell dimensions (Hc/D = 0.50 and Dc/D = 1.15). Moreover, peak particle velocity and excess pore water pressure at monitored points in the surrounding environment experience reductions of 62% and 87%, respectively, demonstrating substantial vibration attenuation. The study does effectively highlight the novelty of the confined sand cell approach, positioning it as a more targeted, efficient, and cost-effective alternative to existing methods, especially for conditions where large-scale, deep vibrations are a concern.

The stability of a slope located between the Belen and El Espejo sectors, Merida, Venezuela with high seismic hazard, due to the presence of the active Bocono Fault, which together with high rainfall and steep slopes, represent triggering factors where the slopes are prone to landslides. Through the Limit Equilibrium (LEM) and the Finite Element (FEM) Methods, we seek to identify the area's most prone to damage in the event of a landslide. The slope studied is located in an area unfavourable geomorphological zone, due to the erosive action of the Chama river that undermines it, generating gullies with detrital flows that affect its stability. The study of slope stability began with the compilation and review of bibliographic, the collection of soil samples for laboratory tests and the calculation of its properties and geomechanically parameters. The data obtained are used for the study of soil behavior and the calculation of the safety factor through of the Slide and Plaxis programs. It was determined that the slope is more unstable for the saturated pseudo-static condition in both programs. It is recommended to implement bioengineering as slope stabilization methods, in the upper zone of the slope, where there is damage to houses that are in danger, suggesting the biomantle, double torsion mesh and passive anchors, as a proposal of recommendation for the stabilization of the slope studied.

The continuous demand for urban development, along with the construction of new buildings, highways, and infrastructure, creates an increasing necessity for excavation activities. Deep excavation near existing buildings can lead to ground instability, potentially causing structural damage to nearby properties. This research aims to investigate methods for enhancing buildings stability from the initial stages of construction, focusing on protecting structures from potential future adjacent excavations. This study utilizes a skirt-raft foundation system, modeled using the finite element software PLAXIS 3D, to evaluate its effectiveness in improving stability and protection. The study analyzed the behavior of raft foundations in clay soil adjacent to excavations ranging from 1 m to 10 m and compared this with the performance of raft foundations with added skirt foundations. The comparison focused on settlement, rotation, and lateral movement of the excavations to assess potential building damage. The results showed that incorporating a skirt foundation significantly enhanced structural stability and reduced excavation-related damage. The implementation of a skirt foundation to a depth of 0.5B (where B is the foundation width) for excavations of similar depth has been shown to significantly reduce damage levels from medium or high to light while also decreasing differential settlement by 80%. It is recommended that adjacent excavation depths should not exceed 0.25B. However, if a skirt foundation is constructed at a depth of 0.5B, the excavation depth can be safely extended to 0.75B.