Driven piles provide excellent stability to a structure by resisting lateral and vertical loads, such as those from wind and earthquakes. The impact force generated by the hammer causes the soil to compress around the pile, providing additional support and stability. In the current investigation, the overall behaviour of driven piles in multi-layered soil is assessed through finite element simulation. The soil domain comprises clay of soft consistency, loose sand, clay of medium consistency and dense sand at the bottom. The stroke applied on the top of the pile is simulated with the help of a harmonic loading system. In the study, the influence of parameters namely, pile diameter, water table depth, amplitude multiplier and soil constitutive models are examined on the behaviour of the driven pile. The results are presented in terms of settlement of the pile, excess pore water pressure phenomenon and shear stress development along the pile length. It is noticed that with the existence of a water table at the ground level, a high value of excess pore water pressure is generated at the bottom of the pile which enhances the settlement of the pile.

A three-dimensional numerical analysis is conducted on a group pile adjacent to a deep multi-strutted excavation in a naturally occurring soil profile comprising both cohesive and non-cohesive layers. The contrasting soil layers affect the soil stiffness, strength, and deformation characteristics, thereby impacting the load transfer mechanism within a pile group. The primary aim of this study is to specifically understand how the presence of a noncohesive soil layer within a predominantly cohesive soil profile, affects the behavior of a pile group during excavation. By systematically varying the position and thickness of the soil layers, the analysis highlights the significance of considering the actual soil profile's inherent heterogeneity rather than assuming a homogeneous clay layer. 19.2% and 17% deviations respectively are observed for pile group settlement and lateral deflection when a homogeneous clay layer is considered instead of the natural soil profile. The findings also show that the position of the non-cohesive soil layer within a predominantly clay soil profile is more critical than its thickness in determining the pile response to excavation-induced changes. The non-cohesive soil layers within the excavation depth, significantly influence the lateral and axial pile behavior, while those below the final excavation depth have a limited impact. A theoretical simplified framework is proposed for the preliminary assessment of the excavation-induced effect on an adjacent pile group. This simplification helps minimize the initial calculation time and effort while capturing the significant factors affecting the pile group behavior near the excavation.

This paper investigates the consolidation behavior of multi-layered viscoelastic soils considering groundwater. First, the fractional Merchant viscoelastic model is introduced to describe the behavior of multi-layered viscoelastic soils considering groundwater. Later, the governing equations are extended to a viscoelastic medium by virtue of the elastic-viscoelastic corresponding principle in the Laplace-Hankel domain. According to the extended precise integration method, the soil layer is divided into a series of layer units. Then the relationship between general stress vector and general displacement vector on the top and bottom planes is established. Every two adjacent layer units are combined into one layer in each computational iteration. The solutions in the Laplace-Hankel domain are obtained by considering the boundary conditions, and numerical inversion is performed to obtain the solutions in the physical domain. The practicability of the present method is assessed by comparing the numerical results with those in the existing literature and done by ABAQUS. Finally, the effects of groundwater table, properties of the soils above groundwater table, load depth, viscoelastic parameters, and soil stratification are investigated.

Geo-materials naturally display a certain degree of anisotropy due to various effects such as deposition. Besides, they are often two-phase materials with a solid skeleton and voids filled with water, and commonly known as poroelastic materials. In the past, despite numerous studies investigating the vibrations of strip foundations, dynamic impedance functions for multiple strip footings bonded to the surface of a multi-layered transversely isotropic poroelastic half-plane have never been reported in the literature. They are first presented in this paper. All strip foundations are assumed to be rigid, fully permeable, and subjected to three types of time-harmonic loadings. The dynamic interaction problem is investigated by using an exact stiffness matrix method and a discretization technique. The flexibility equations are established by enforcing the appropriate rigid body displacement boundary conditions at each footing-layered soil interface. Numerical results for dynamic impedance functions of two-strip system are presented to illustrate the influence of various effects on dynamic responses of multiple rigid strip foundations.