Field study on the treatment of collapsible loess using vibratory probe compaction method

A successful case history of using vibratory probe compaction method to treat collapsible loess foundation is presented in this study, where the equipment and execution process of the compaction method are introduced in detail. The results are presented of a project at the construction of the Zhong-Lan high-speed railway, comprising laboratory tests and field tests including standard penetration tests and cone penetration tests. Spectral analysis of surface wave tests were conducted before and after treatment. The test results indicated that the initial average 0.0185 -collapsibility coefficient of loess samples at different treatment depths that reduced to 0.003 after vibratory probe compaction at points spaced 1.2 through 1.4 m. The engineering properties of loess were effectively improved and the surface wave velocity of the subsoil in the treatment depth increased by about 15% similar to 36% compared with 140 m/s before treatment, resulting in a denser soil. The compaction effect in terms of collapsibility coefficient and density at 1.2 m spacing was more pronounced than at 1.4 m spacing. The vibratory probe compaction method was successful for the treatment of collapsible loess.