Influence of structural strength on geotechnical properties of intact red clay

Abstract

Red clay has the characteristics of high water content, high porosity ratio, and complex inverse profile, which can hardly meet the requirement strength and is of most importance in the prevision of foundation or landslides which are mainly controlled by the red clay of geotechnical properties. Hence, the X-ray diffraction test, oedometer test, triaxial un-drained (CU) test, and scanning electronic microscope test are conducted to study the geotechnical properties of intact red clay. In this paper, firstly, the effect of depth on the properties of intact specimens is investigated, including mineral component, dry density, free swell ratio, water content, void ratio, and grain size distribution. Then, the characteristics of compression behavior and its development with depth are investigated. A normalization method is carried, considering the effect of structure. Secondly, CU test is performed to analyze the mechanical behavior and strength parameters of intact, reconstructed, and slurry specimens. In addition, the classification of intact red clay is used to characterize the compression behavior. The intact specimens can be classed as structural un-compacted and structural over-consolidation soil. Moreover, an attempt is made to explain the mechanism of structural strength enhancement in intact red clay, involving interlocking strength, bonding strength, and compaction strength.