Undrained Shear Strength of Soft Soil in Some Areas of Vietnam’s North Central Region

Geotechnical Engineering Journal of the SEAGS & AGSSEA ISSN 0046-5828

Vol. 54 No. 1 March 2023

Undrained Shear Strength of Soft Soil in Some Areas of Vietnam’s North Central Region

Nguyen Thi Nu, Bui Truong Son, Nguyen Thanh Duong, Do Minh Ngoc, and Vu Dinh Tho

ABSTRACT: The paper aims to investigate the undrained shear properties of soft soil distributed in some areas of Vietnam’s North Central region. To study the undrained shear strength properties of soft soil, different test methods in the laboratory and in – situ at different sites were carried out. In the laboratory tests, the undrained shear strength of soft soil was determined by an undrained unconsolidated compressive test, unconfined compressive test, and consolidated undrained compression test. For the in-situ test, vane shear tests were performed at different depths in the borehole. The experimental results showed that there were various characteristics of undrained shear strength of soft soil in the study area. The undrained shear strength of soft soil depended on many factors, such as liquid limit, dry unit weight, void ratio, and plasticity index. The research results also showed that the correlations between the undrained shear strength of soft soil and physical properties have high determination coefficients.

KEYWORDS: Undrained shear strength, Qu test, UU test, CU test, Field vane shear test, Soft soil.