硅酸钾对遗址土的渗透加固机制及改进特性研究

Research on infiltration reinforcement mechanism and improved properties of potassium silicate for earthen relics soils

即一定模数硅酸钾溶液,是保护加固土遗址的一种无机化学材料。通过近20年的实践证明,PS材料具有增强遗址土体强度和抵抗外界环境破坏的作用。但PS渗透加固遗址土的微观机制以及加固后遗址土宏观特性的改变如何,并没有取得显著的突破和统一的认识。利用3%体积浓度的PS溶液渗透加固室内击实制备的良渚遗址土试样,渗透初始含水率为13%、17%、19%、21%和25%,并对加固前、后试样进行非饱和直剪、压汞和扫描电镜试验,旨在解决上述两个问题。基于压汞试验得到的双峰孔隙分布模型,提出了PS渗透加固遗址土的两种微观加固机制,并通过扫描电镜试验结果验证了加固机制,同时提出了用于表征两种加固机制指标参数P1和P2。通过研究发现,加固指标P1和P2能够较好地描述在不同含水率下经PS加固试样的相关改进特性如土-水特征曲线和剪切特性的变化规律。研究成果为PS的进一步应用和加固保护土遗址研究提供了新的方法和手段。

PS, a certain modulus potassium silicate, is a kind of inorganic chemistry materials to protect and reinforce earthen relics. It is proved that PS material can enhance soil strength and the resistance of external environment damage by nearly twenty years of practice. However, the reinforcement mechanism and related improvement of macroscopic properties are not fully understood and invested until now. To contribute to this field of research, Liangzhu earthen relics soil specimens with initial water contents of 13%, 17%, 19%, 21% and 25% are reinforced by PS with 3% volume concentration through infiltration method. After that, scanning electron microscope （SEM）, mercury intrusion porosimeter （MIP） and direct shear test are employed to compare the difference between unreinforced specimens and reinforced specimens respectively. Based on bimodal pore size distribution obtained by MIP and SEM, two sorts of microcosmic reinforcement mechanisms of PS, which are represented by indexes P1 and P2, are proposed to characterize the two mechanisms. Through the study, the above two indexes of specimens can characterize the variation of improved properties such as shear strength characteristic and soil-water characteristic curve very well at different reinforcement water contents. These conclusions provide a further research method and means for the application of PS material.