石灰加固膨胀土机理研究综述和展望

对石灰加固膨胀土机理的研究现状进行了综述,明确了石灰加固膨胀土性质变化的过程:离子交换是石灰加入土中最先发生的反应,之后发生絮凝和结团、结块,使膨胀土的性质快速发生变化。现有机理研究成果表明:硬凝反应是一个长期的过程,能提高土体的强度;碳酸化和结晶作用也有助于提高土体的强度;扩散和胶结是使土体内部产生变化的原因;微观结构和矿物组成的变化是石灰改性膨胀土的内因。提出了进一步从土中离子含量的定量变化、土的微观结构的定量分析、以及石灰加固膨胀土中吸力的变化等方面开展石灰加固膨胀土机理研究的新思路;并阐述了石灰加固膨胀土可能带来的环境污染基本上可以忽略。研究工作将有助于进一步揭示石灰改性膨胀土的机理。

A Review and Prospect on the Mechanism of Expansive Soil Stabilized by Lime

Previous research results on the mechanism of expansive soil stabilized by lime are summarized.It is clear that cation exchange is the first reaction when lime is added into expansive soil,followed by flocculation and agglomeration.These reactions change the soil’s properties quickly.Pozzolanic reaction of lime and soil is a long-term process,which helps increase the strength of expansive clay.Carbonation and crystallization also contributes to the strength increase of expansive soil.Diffusion and cementation are the causes of interior changes in the soil. Microstructure and mineralogy changes are the internal causes of stabilization of expansive soils.Moreover,analysis on the quantitative cation exchange,quantitative microstructure change,and soil suction change of expansive soil during lime treatment would be new research focus.These investigations will further reveal the fundamental mecha-nism of expansive soil stabilized by lime.The review also indicates that the possible environmental pollution caused by lime stabilization can be ignored.