水泥土搅拌法加固冲填土软土地基的微观试验

Micro-experiments in Cement-mixed Soils on a Dredger Fill of Soft Ground

摘要:

针对某工程冲填土软土地基水泥土搅拌法处理过程中的冲填土与自然软土加固效果差异问题,从化学成分与物理结构等微观角度出发,分别对冲填土和自然软土的原状样、加固样进行了X射线衍射试验和扫描电镜试验两种微结构试验,对比分析了导致这种加固效果差异的微观机理及其形成原因.研究发现,物理微结构对冲填土软土地基的水泥土搅拌法加固效果存在重要的影响.虽然水泥土搅拌法加固冲填土与自然软土的化学反应是类似的,但加固后的土体在物理微结构特征上却差异显著,并导致加固土体宏观强度表现上的不同.因此,应采取相应的施工措施,改良冲填土的微观结构特征,优化地基加固效果.

关键词:水泥土; 水化产物; 物理微结构; X射线衍射试验; 扫描电镜试验

Abstract:

To investigate the different effectiveness between dredger fill and natural soft soil in the cement-mixed improvement processes of an engineering case,two kinds of micro-experiments on dredger fill and natural soft soil before and after cement-mixed processes were carried out by using X-ray diffraction(XRD)and scanning electron microscope(SEM)tests in the view of chemical and physical microstructures.It is found that the physical microstructures have an important effect on the reinforcement performance of cement-mixed soils.Although the chemical reactions of cement-mixed processes are similar in both dredger fill and nature soft soil,there are significant differences in the microstructures of treated soils,which can affect the macro-scale strength directly.Therefore,in order to optimize the improvement in soft ground engineering,proper construction measures should be taken to improve the microstructures and mechanical properties of the dredger fill.

Key words:cement-soil; hydration products; physical microstructure; X-ray diffraction; scanning electron microscope