曹妃甸海积软土微观结构特征试验研究

Experimental Study on Microstructure of Marine Soft Soil based on SEM

海积软土的微观结构可反映其物理力学性质,滨海地区公路工程施工中受具有特殊微观结构的海积软土的影响较大。以曹妃甸海积软土为研究对象,运用扫描电镜(SEM)微观结构试验方法,获得200kPa、250kPa、300kPa、350kPa、400kPa、600kPa下曹妃甸海积软土土样的微观结构扫描图像,定量计算土样微观结构参数并分析其演变规律特征。研究表明,曹妃甸海积软土为絮凝结构,在逐渐加压作用下,土样结构单元逐渐破碎且形状发生变化,但结构单元与孔隙的分布特征变得有一定相似性,曹妃甸海积软土的压密施工过程为土样结构单元和孔隙由初始无序状态向定向和有序性的演变过程。

The microstructure of marine soft soil can reflect its physical and mechanical properties,and it is greatly influenced by marine soft soil with special microstructure in highway construction in coastal ar⁃ea.Taking Caofeidian marine soft soil as an example,scanning electron microscopy(SEM)microstructural test method was used to obtain the scanning images of the microstructures of marine soft soil under 200kPa,250kPa,300kPa,350kPa,400kPa and 600kPa loads.The average shape coefficient,orientation frequency,anisotropy and determination of marine soft soil under different loads were calculated.Direction⁃al probability entropy,directional fractal dimension and other parameters were analyzed,and structural unit and pore morphology parameters and pore arrangement characteristic parameters were analyzed.The results show that with the increase of pressure,the structure unit gradually breaks up,the shape be⁃comes irregular,the structure unit and the pore arrangement become orderly,and the consolidation of ma⁃rine soft soil is a process of structural unit and pore changing from disorder and directional to orderly and directional.