石家庄环城公路泥炭土微观结构及工程特性研究

Study on peat soil micro-structure and its engineering properties related to Shijiazhuang encircling city highway

依据石家庄环城公路（省道 S101）泥炭土地基处理工程，采用扫描电子显微镜、X 射线衍射、压汞试验等对泥炭土微观结构进行分析，得出其微观结构是由微团聚体和团粒共同构成，土颗粒多呈平直的板状或管状。泥炭土孔径一般为1～5μm，孔隙呈正态分布，架空的大孔隙较多，孔径可达10～30μm。泥炭土与原状黏土主要矿物成分的不同就在于含有硅磷酸铝分子筛（ AlSi2 P3 O12），它对泥炭土的结构和刚度有重要影响，是造成泥炭土具有多孔结构、压缩性高、含水量大、强度低等工程特性的直接原因。结合泥炭土的物理力学性能试验，揭示了泥炭土微观结构与工程特性之间的本质联系，对其工程应用具有参考价值。

T he paper studies the micro-structure of peat-soil subgrade of Shijiazhuang belt highway （ also known as S101） via scanning electron microscope,x-ray diffraction and mercury pressure test,and the results show that the structure displays the form of micro-aggregate and conglomeration,with most of the grain being flat and tubular. Generally,the aperture of such soil ranges 1 ~5 μm in length,as the pore distributes in line with the normal discipline. However,the fly-over holes with large aperture are large in number,whose diameters stand at 10 ~30 μm. Compared with undistributed soil,peat soil stands out in configuration,as it has Aluminum Silicon Phosphate （ AlSi2P3O 12） . T he component,directly affecting the soil structure and its rigidness,is the reason behind the multi-aperture structure,highly compressible and moisture property,and the fragile strength of the soil. T he paper conducts mechanical tests to unveil the connection between the micro structure of the soil and its engineering properties,the results are of value for further studies.