APPLICATION THE POINT FOUNDATION (PF) METHOD FOR SOFT SOIL IMPROVEMENT: A CASE STUDY FROM VETNAM

Bui Truong Son

doi:10.46717/igj.53.2d.1ms-2020-10-23

Abstract

The point foundation method is the head enlarged cement deep mixing columns with high-quality control which can be used for soft ground improvement. The article aims to present the application of this method to treat soft soil for the foundation of Samse Vina factory, Ninh Binh province. The thickness of soft soil varies from 5.4 m to 7.4 m with high compressibility and low shear strength. Thus, point foundation was used to improve this layer. The prediction methods of soil bearing capacity and the settlement on the point foundation were calculated. After the treatment of soil, the unconfined compression strength of the point foundation column was determined and the static compression test for the point foundation column was also performed. The research results show that this method can significantly reduce the settlement of shallow footing and improved the bearing capacity of the soil. The final settlement of shallow footing was smaller than 2.54 cm and the bearing capacity of soil treatment can be satisfied with the requirement of construction building. This is a successful case of the application of point foundation to improve soft soil in Vietnam.

Highlights

Vietnam has two large deltas, including Red river and Mekong deltas
The soft soil is widely distributed in the area of Samse Vina factory with the thickness varying from a few meters to more than 10 meters
The soft soil layer distributes at a shallow depth; has a low bearing capacity and cannot meet the construction load

Summary

Introduction

Due to the deposition of young sediments, soft soil is widely distributed in these deltas. The thickness of soft soil layers varies from a few meters to more than 30-50 meters (Bui Truong et al, 2020; Giao and Hien, 2007; Nu et al, 2020; Nguyen Thi et al, 2020 and Nu and Thinh, 2020). In Vietnam, many methods have been used for the treatment of soft soil such as sand column, sand well, prefabricated vertical drain (PVD), and cement deep mixing (CDM). In Vietnam, soft soil can be improved by mixing with cement and coal bottom ash from thermal power plants (Nu et al, 2019 and Nguyen Thi et al, 2019)

Methods

Results

Conclusion