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通过室内试验,考察了去离子水及不同浓度总磷溶液对黏土物理力学性质的影响,并通过土体矿物成分含量及微观形貌分析,对总磷溶液与黏土作用机制进行了初步探讨。结果表明,总磷对土体物理力学性质影响明显:黏土塑性指数随着总磷溶液浓度的增大而减小,有效黏聚力先增大后减小,有效内摩擦角则随着溶液浓度的增大而增大;各浸泡条件下,黏土应力-应变关系曲线变化规律基本一致,均呈应变硬化现象,土体剪切峰值随总磷溶液浓度的增大先增大后减小;总磷溶液与土体间相互作用主要包括离子交换作用、胶结作用及微生物分解作用,并同时受到孔隙液介电常数及黏滞性的影响,这些作用通过改变黏土的矿物成分含量,使其微观形貌及孔隙特征发生明显变化,最终导致土体的宏观力学特性改变。
The effects of deionized water and different concentrations of total phosphorus solution on the physical and mechanical properties of clay were investigated through laboratory experiments. The mechanism of action of total phosphorus solution and clay was discussed through the analysis of mineral composition and microstructure of soil. The results show that total phosphorus has obvious effect on the physical and mechanical properties of soil. The clay plasticity index decreases with the increase of total phosphorus concentration. The effective cohesion first increases and then decreases. The effective internal friction angle decreases with the increase of solution concentration , And the stress-strain curves of clay are basically the same under all soaking conditions. All show the phenomenon of strain hardening. The shear peak of soil first increases and then decreases with the increase of total phosphorus concentration. The interaction between the phosphorus solution and the soil mainly includes ion exchange, cementation and microbial decomposition, and is also affected by the dielectric constant and viscosity of the pore fluid. These effects change the mineral content of the clay and make it microscopic The appearance and pore features change obviously, which eventually leads to the change of macroscopic mechanical properties of the soil.