Experimental study of the effect of total phosphorus on physico-mechanical performance of clays

In order to find the effect of total phosphorus on physico-mechanical performance of clay, samples have been tested with deionized water and total phosphorus solution with different concentrations in laboratory, and the interaction mechanisms of clays and total phosphorus are revealed by mineral and microscopic analysis. The results make clear that the total phosphorus has significant influences on physico-mechanical performance of clay: the plasticity indices of samples decrease with the increasing concentration of total phosphorus solution, the effective cohesive strength is increased and then decreased, and the effective friction angle increases with the increasing concentration; the strain hardening phenomenon appears in the stress-strain relationships, and the variation of stress-strain curve of samples soaks in deionized water and total phosphorus solution is almost the same. The peak shear strength of samples manifests as a trend of increase and then it decreases with the increasing concentration of total phosphorus solution. The mineral composition, microstructure and physico-mechanical performance of clays are affected by the interaction between total phosphorus and clays, including ion exchange, cementation, microbial decomposition as well as the dielectric constant and viscosity of pore solutions.