Vertically Dynamic Response of an End-Bearing Pile Embedded in a Frozen Saturated Porous Medium under Impact Loading

Lu Cao,Weiwei Duan,Qiang Li,Bin Zhou,Wenli Shu

doi:10.1155/2019/8983128

Abstract

A frozen soil is a multiphase medium composed of solid particles, ice, and water, and the cementation between the solid particles and ice strengthens with a decrease in temperature. Based on the theory of a composite solid-state saturated porous medium, a uniform solution for the vertical vibration of an end-bearing pile in a frozen soil is derived analytically. The axial displacements under impact loading in the time domain are calculated by using the numerical inverse transformation technique. The solution can degenerate into an end-bearing pile in a saturated soil layer as the temperature approaches the freezing point. If the cementation between the solid particles and ice is ignored, the amplitude of the displacement will be overestimated. The numerical results show that temperature has a significant impact on the dynamic responses of the pile due to variation of the ice content and, consequently, of the cementation between solid particles and ice.

Highlights

In many high-latitude regions of the world, there are large numbers of permafrost and seasonally frozen soils
For the first key problem, the frozen porous medium is considered as consisting of a composite solid skeleton and pores formed by the soil particle, and the pores are full of water and air, in which parts of the water freeze to the ice. erefore, there are two solidphase matrices, and generally, there is an interaction between the solid and ice; and the cementation strengthens with the deceasing temperature
Leclaire et al established a kinematic model of the frozen saturated porous medium consisting of three phases of soil particles, ice, and water, ignoring the interaction between the solid and the ice phases [6]. en, an ultrasonic test based on the established frozen porous media model verified the existence of multiple body waves predicted by the model [7]

Summary

Introduction

In many high-latitude regions of the world, there are large numbers of permafrost and seasonally frozen soils. E virtual pile model originated by Muki and Sternberg [17,18,19,20,21,22,23,24] and the simplified continuum analytical model proposed by Nogami and Novak [25] are used to investigate the dynamic load transfer problem of a one-dimensional elastic rod in the stratum. The dynamic responses of a pile embedded in a soil layer under transient loading in the time domain are of concern in practical engineering.

Mathematical Model

Solution of Interaction between the Pile and Soil

Numerical Results and Discussion

Conclusions