# Responses of Laterally Loaded Single Piles Subjected to Various Loading Rates in a Poroelastic Soil
## 1 Introduction
Their results show that soil yielding significantly increases the pile bending moments and lateral displacements. Finite difference analysis using FLAC3D has also been performed on a single pile subjected to lateral load [11]; different pile cap sizes and pile lengths have been considered. The findings were that the influence of the pile cap on the soil is mainly within the first quarter of the pile length, and that the pile cap would affect the location of the maximum soil resistance, and if the critical load is reached, the maximum soil resistance would increase with the sizes of the cap. [PERSON] and [PERSON] [12] developed a continuum-based nonlinear analysis of laterally loaded piles. The nonlinear behavior of sands and clays were represented by the nonlinear elastic constitutive model, in particular, the hyperbolic modulus-reduction model. It was concluded that the lateral load of pile head settlement can be overestimated by 60-80% if linear elastic analysis is performed with small-strain elastic modulus instead of their nonlinear analysis. [PERSON] and [PERSON] [13] conducted numerical analyses of single pile and pile group in clayey soils subjected to monotonous lateral loading using the FE program ABAQUS on free head and embedded capped piles. Their results show that pile cap size influences the lateral capacity of single pile, while the pile-soil-pile interaction and the cap embedment depth affects the resistance in the leading pile of the pile group. [PERSON] et al. [14] numerically examined the effect of the pile cap on lateral capacity of a single pile with and without a pile cap in clayey soil, also using the FE program ABAQUS. They investigated the influence of cap area, embedded depth and vertical load on the pile's lateral capacity and found that the lateral resistance of the pile is influenced by the embedment depth and the thickness of the pile cap; the larger the cap's surface area, the greater the pile cap's lateral resistance. The vertical load in the case of pile without cap has little influence on the capacity but in the case of pile with cap, the vertical load could significantly raise the lateral capacity of the pile. [PERSON] and [PERSON] [15] numerically analyzed the interaction of pile-soil-cap under lateral load, taking into account the effects of pile spacings and pile diameters. The analysis was conducted using Plaxis 2D and under drained condition with Mohr-Coulomb failure criteria. The conclusion was that the greater the depth of the pile cap from the ground surface, the greater the cap's lateral resistance. To study the influence of excess pore-water pressure build-up on the response of laterally loaded single micropiles, [PERSON] and [PERSON] [16] performed a three-dimensional finite element simulation with [PERSON]'s theory for the fluid-soil skeleton coupling. Their soil was represented by an elastoplastic constitutive relation with a non-associated Mohr-Coulomb flow rule. It was found that the excess pore fluid pressure is mainly induced in the proximity of the pile head, and it dissipated quickly. Geotechnical engineering problems require a thorough understanding of the relationship between the porous soil and the interaction between the various multiphysics. The characteristic of a porous soil, in which a pile is buried, is that it generates excess pore-water pressure, which reduces the effective stress of the porous soil and, hence, its shear strength, which could lead to disastrous consequences. The term used to describe the interaction between the fluid flow and solids deformation within a porous medium is called \"poroelasticity\". Most of the soil-pile interaction simulations presented above involved only the solid mechanic part of the problem; simulation based upon the poroelastic constitutive framework has rarely been encountered, probably, because simulation based on solid mechanics without accounting for the fluid flux generated through the pores space of the soil often leads to a quick result.