(NH4)2CO3作用下饱和红黏土的崩解效应

为研究(NH₄)₂CO₃溶液对红黏土崩解性的影响,以桂林红黏土为研究对象,通过自制的崩解装置,测试不同浓度(NH₄)₂CO₃溶液作用下饱和红黏土的崩解特性。比较红黏土与(NH₄)₂CO₃作用前后溶液的pH值、土体C和N元素含量及微形貌,分析崩解的微观机理。同时,结合溶液作用下抗剪强度和渗透性探讨崩解行为。试验发现,饱和红黏土的崩解性随溶液浓度增大而增大;其崩解过程可划分为快速崩解、稳定崩解和完成3个阶段,第Ⅰ阶段持续时间较短,主要是土样从环刀脱出过程中扰动所致;第Ⅱ阶段持续时间长,为崩解的主要阶段,与结合水膜厚度、粒间作用力、胶结作用、强度和渗透性等诸多因素密切相关。

Disintegration Effect of Saturated Red Clay under the Action of (NH4)2CO3

The disintegration characteristics of saturated red clay from Guilin were examined under the action of (NH₄)₂CO₃ solution of different concentrations through a self-made disintegration device. The microscopic mechanism of disintegration was analyzed from aspects including the pH value of solution, the content of elements C and N in the soil, as well as the micromorphology of soil before and after the action of (NH₄)₂CO₃. Meanwhile, the macroscopic effect of disintegration was discussed in terms of shear strength and permeability. Test results manifested that the disintegration of saturated red clay intensified with the increase of solution concentration, and the disintegration process was divided into rapid, constant and stable stages. The first stage, which lasted a short time, was mainly caused by disturbance of the ring cutter; and the second stage, as the main stage of disintegration and lasting long, was closely related with the thickness of water film, the intergranular forces, the cementation force, the strength and the permeability of soil.