Study on Soil Spring Model for Pipe and Silty Clay Interaction Based on Physical Model Test

Liyun Li,Xiangjian Wang,Junyan Han,Patrice Berthod

doi:10.1155/2021/2838605

Abstract

The previous soil spring model cannot describe the nonlinear characteristics of soil in elastic stage, and there are some shortcomings in the selection of soil spring parameters in some published codes. Meanwhile, the literatures about the spring model for pipe and silty clay interaction are rare. Thus, a series of pipe-silty clay interaction tests are conducted, and some corresponding experimental results are obtained. The effects of soil properties, pipe diameter, and embedment depth on the horizontal resistance of soil are studied. Based on the experimental results, the failure modes of soil are analysed, and a formula to calculate the peak resistance of soil and the corresponding displacement to peak resistance are proposed. Finally, a method to describe the nonlinear spring stiffness coefficient of silty clay is recommended.

Highlights

In the analysis and design of buried pipeline, soil spring model is often adopt to describe the action of soil on the pipeline, in which the soil around pipeline is equivalent to a three-dimensional soil spring, and many fruits have been obtained based on the soil spring model [1,2,3,4,5,6,7,8,9,10]
For the transverse soilpipe interaction, it is common practice to idealize the resistance displacement curve into a linear elastic-perfectly plastic model represented by two straight lines, as shown in Figure 1, so that the properties of soil spring can be determined by getting the peak soil resistance and its corresponding displacement
Based on the experimental results, the authors discuss the determination of key parameters of soil spring and the mathematical description of soil spring coefficient, in order to provide an experimental basis for the laying of pipelines in silty clay site in Beijing region

Summary

Introduction

In the analysis and design of buried pipeline, soil spring model is often adopt to describe the action of soil on the pipeline, in which the soil around pipeline is equivalent to a three-dimensional soil spring, and many fruits have been obtained based on the soil spring model [1,2,3,4,5,6,7,8,9,10]. Trautmann and O’Rourke [12] conducted a model test of pipe-sand interaction and suggested a method for determining the parameters of transverse soil spring in sandy soil. Pipe-soil interaction in clayey soil, Oliveira et al [20] carried out the centrifuge physical model test of pipe-soft clay interaction and proposed a method for calculating the ultimate bearing capacity of soft clay when the pipeline moved laterally. Liu et al [21,22,23] conducted a series of pipe-soil interaction model tests on soft clay in Bohai region, analyzed the failure mode of the soil, and proposed a formula for calculating the peak resistance of soil. In view of the above discussion, the authors carried out some physical model tests of pipe-soil interaction with the silty clay in Beijing region. Based on the experimental results, the authors discuss the determination of key parameters of soil spring and the mathematical description of soil spring coefficient, in order to provide an experimental basis for the laying of pipelines in silty clay site in Beijing region

Physical Model Tests

Reliability Verification of Experiment

Results and Discussion