Effect of Seabed Instability on Pile Soil Pressure

Abstract

In a narrow sense, the seabed instability means that the shear failure, liquefaction or scour occurs in the seabed; in a broad sense, the seabed instability means that the soil displacement occurs in the seabed. The seabed instability widely exists in the ocean environment, however, it has not been considered in the current design and calculating methods of the marine pile foundation, consequently, the accuracy and reliability of design results can not be guaranteed, which may induce that the ocean buildings are not safe enough. Therefore, it is necessary to found one new method to calculate the pile soil pressure with the influence of seabed instability, before which, one approximate mathematical model shall be established. Thus, based on Biot consolidation theory and fictitious pile technique, this paper firstly establishes a mathematical model describing pile-soil interaction considering the seabed instability, the soil pressure obtained through which can cover such factors as ocean environment, seabed soil condition and pile condition etc. And then, this paper introduces one mathematical solver (FlexPDE) to get the numerical solutions of the mathematical model presented. Finally, based on the numerical solutions, this paper discusses the effects of pile deflection, wave height, water depth, soil modulus, pile length and diameter on soil pressure, and some conclusions are obtained, which can be referenced in the design of ocean pile foundation.