Use of Foamed Cement Banking for Reducing Expressways Embankment Settlement

Yuedong Wu,Hui Liu,Jian Liu

doi:10.3390/app112411959

Abstract

Expressways are often built on soft ground, the foundation of which is not processed adequately during the construction period. Consequently, the traffic safety and embankment stability will be seriously affected due to uneven settlement. The technology of holing the embankment and replacing foamed cement banking (FCB) could control the settlement of an embankment without road closure, thus reduce the impact of construction on normal operation of highways. In this paper, the principle of FCB is described. Additionally, a sedimentation ratio calculation method, through the analysis of the settlement load ratio, is proposed for calculating the roadbed replacement thickness. This paper takes the example of the test section EK0 + 323 on Shen-Jia-Hu expressway in Zhejiang Province and combines with site settlement monitoring data to confirm the effectiveness of the calculation method proposed.

Highlights

With the rapid development of expressway construction, in China, construction on soft ground is sharply increasing, such as Shen-Jia-Hu Expressway that passes through soft soil [1,2]
In order to reduce post-construction settlement, the embankment is replaced with light soil to reduce the overburden load and control the settlement [7,8]
The lightweight soil’s cohesion, global strength, bulk density, and other parameters can be adjusted by adjusting the output of cement and foam [9]

Summary

Introduction

With the rapid development of expressway construction, in China, construction on soft ground is sharply increasing, such as Shen-Jia-Hu Expressway that passes through soft soil [1,2]. Owing to shortened construction periods and to the rheological properties of soft soil, among other reasons, the embankment after settlement of many highways opened abroad is too high, which does not meet relevant regulatory requirements (i.e., post-construction should be less than 30.0 cm) [3]. In order to reduce post-construction settlement, the embankment is replaced with light soil to reduce the overburden load and control the settlement [7,8]. As FCB’s bulk density is only conventional soil bulk density of 1/4 to 1/8, its use as a replacement of embankment material [15,16,17], can reduce the base load pressure, but can reduce the total settlement and differential settlement [18]. Replacing the undisturbed soil with lightweight soil to process the post-construction settlement of expressway under traffic control seriously affected highway traffic operations. There are no closed roads (ramps) during construction, the lightweight soil is being put down to achieve subgrade compactness, that causes huge economic losses due to the road closure

Methods

Findings

Discussion

Conclusion