Mechanical characteristics of soft clay treated with fibre and cement
ABSTRACT: In this study, the influence of three types of fibre – polypropylene, recycled carpet and steel – on the mechanical properties of cement-treated clay is investigated. Cement-treated clay specimens were prepared with cement contents of 5%, 10% and 15% by weight of dry soil, and cured for 14 days. To investigate and understand the influence of different fibre types and contents, three different percentages of fibre content were adopted. The results of unconfined compression tests on 90 cylindrical samples of cement-treated clay with varied cement and fibre contents are analysed to discern the relationships between these parameters and the key mechanical properties, including unconfined compressive strength and stiffness of treated soil. Furthermore, indirect tension test results of a further 90 treated soil samples have been used to determine the influence of fibre and cement content on the tensile strength of the treated soil. The fibre reinforcement increases the peak compressive strength. The a...
Accumulative Strain of Sand-Containing Soft Soil Reinforced by Cement and Sodium Silicate under Traffic Loading
The accumulative strain of sand-containing soft soil is crucial to the stability of the construction of embankment engineering such as expressways and high-speed railways. However, little attention has been devoted to the accumulative strain of sand-containing soft soil. In the current study, a series of cyclic triaxial tests were performed to investigate the accumulative strain of sand-containing soft soil reinforced by cement and sodium silicate under traffic loading. In addition, the accumulative strain model was proposed to describe the characteristic of accumulative strain. The results show that for the specimens with a high sand content (25%, 30%, and 35%), the accumulative strain increases obviously with the increase of the sand content. For the specimen with a cement content of 3%, the accumulative strain increases distinctly with the increasing loading time. The accumulative strain is strongly influenced by confining pressure. When the repeated cyclic stress amplitude is greater than 0.17 kN, the increase rate of accumulative strain is greater. The shorter the curing time is, the greater the accumulative strain is. The calculated results of the accumulative strain model show a good agreement with test data. Hence, the accumulative strain model can better describe the characteristic of accumulative strain.
Naturally cemented sensitive soils
Many extremely sensitive or quick clay soils, particularly but not only those found in Canada, show characteristics of natural cementation bonding between particles. These soils include not only th...