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 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.

Industrialization and population growth have made surface areas more valuable, thereby the multi-story buildings have become an absolute necessity. At this point, numeric models became the fastest and simplest way to evaluate the response of soils and structures. The issued factor in the current paper is related to the way of transferring the multi-story building loads to an alluvial stratum and evaluate the accuracy of different cases, in order to save time and economy. For load transfer, the first case (case i) includes uniform distributed load, the second case (case ii) includes the transfer from the basement columns and walls, and the third case (case iii) includes modeling the real state of the building. Mainly, all three cases gave close results in terms of settlement magnitudes of 2.21, 1.96, and 1.81 cm, respectively. It was inspected that case (i) showed 12.8% more deformation than case (ii) and 22.1% more deformation than case (iii). However, the situation is not the same for the settlement pattern, and the under-column and corner effects are neglected in uniform load. Additionally, the bending moments, which is a critical parameter for the design of a reinforced concrete foundation, have developed different results. In case (ii) and (iii) a bending moment of 500 kNm/m is observed in the center column, while in case (i) the moments converge to 0. Therefore, this study highlights the importance of outstanding decision making when assessing the load-transferring mechanism in modeling with numerical methods. The necessity of the determination of the convenient load transfer way depending on the parameter that is crucial in the evaluation of the soil-structure interaction comes to the fore with current paper.

The construction of group foundation pits near subway stations often leads to environmental pollution, thereby causing certain damage to urban ecology. By optimizing the excavation sequence of group foundation pits, the adverse effects on surrounding underground structures and soil during excavation can be effectively mitigated, contributing to the sustainable development of cities. Taking a group foundation pit project in Changzhou as an example, this study utilized the finite element software PLAXIS 3D to simulate various working conditions under different excavation sequences, comparing the deformation of the subway station, shield tunnel, and surrounding soil. The results show that, influenced by the excavation of group foundation pits, the difference between maximum deformation and minimum deformation of shield tunnel is 25.85%, and the difference between the maximum deformation and minimum deformation of the subway envelope is 19.44%. The subway envelope is least affected by the change in excavation sequence. Both the displacement of the subway station and the surrounding soil exhibit a significant cumulative effect, with displacement changes closely related to the distance from the pit to the station and the ground, as well as the amount of soil unloaded in each excavation. Therefore, it is advisable to adhere to the principle of far before near, shallow before deep, small before large during excavation, which facilitates the coordinated development of urban infrastructure construction and the urban ecological environment, providing valuable reference and guidance for the sustainable development of cities.

The paper aims to contribute to the preservation of high valuable historic masonry structures and historic urban landscapes through the combination of geotechnical, structural engineering. The main objective of the study is to conduct finite element analysis (FEA) of bearing saturated soft clay soil problems and induced structural failure mechanisms. This analysis is based on experimental and numerical studies using coupled PLAXIS 3D FE models. The paper presents a geotechnical analytical model for the measurement of stresses, deformations, and differential settlement of saturated clay soils under colossal stone/brick masonry structures. The study also discusses the behavior of soft clay soils under Qasr Yashbak through numerical analysis, which helps in understanding the studied behavior and the loss of soil-bearing capacity due to moisture content or ground water table (G.W.T) changes. The paper presents valuable insights into the behavior of soft clay soils under colossal stone/ brick masonry structures. The present study summarized specific details about the limitations and potential sources of error in Finite Element Modeling (FEM). Further field research and experimental analysis may be required to address these limitations and enhance the understanding of the studied soft clay soil behavior. The geotechnical problems in historic monuments and structures such as differential settlement are indeed important issues for their conservation since it may induce serious damages. It deserves more in-depth researches.

Pile foundations are frequently used to safely transfer enormous loads from superstructures to deeper soil layers in order to support structural weight. Due to earthquakes, piles are subjected to dynamic loadings, which causes significant damage to the foundation as well as the superstructure. Laterally loaded piles vulnerable to earthquakes have a complex dynamic reaction. Earthquake motions shake the foundation ground which can make it unstable. Due to this unpredictable behaviour, the research has been carried out for the last few decades on it but still the behaviour is not understood completely. Therefore, an attempt has been made in this study to investigate the dynamic response of the pile foundation due to earthquakes by performing numerical study using Finite Element (FE) program, PLAXIS 3D. In addition to it, several parameters have been studied to understand the effects of several parameters like soil properties, earthquake features (acceleration, frequency etc.) on pile behaviour, considering soil-pile interaction. It can be stated that this numerical simulation will be useful for the researchers and practicing engineers working on this domain.