上海冻融淤泥质软黏土孔隙结构特征分形研究

Fractals of Pore Structure Characteristic of Muddy Clay in Shanghai After Artificial Ground Freezing

摘要:

对上海第④土层淤泥质软黏土进行了冻融试验、压汞试验和渗透性试验，并结合分形理论，确定了冻融对土壤孔隙结构的影响.根据分形计算，将上海软黏土中的孔隙分为3类.结果表明，在冻融过程中，中孔和大孔的总分形维数和表面分形维数随渗透系数的增加而增大.最后，提出了由小孔隙和中、大孔隙组成的渗透系数与孔隙结构参数之间的关系，小孔隙的渗透系数比中、大孔隙低几个数量级.

Abstract:

In this paper, the muddy clay that obtained from Shanghai 4th stratum has been selected to conduct a freezingthawing test, MIP test, and permeability test to figure out the freezingthawing effect on soil pore structure, especially on pore size distribution and surface fractal dimension. Combined with the fractal theory, the pores in remolded muddy clay have been divided into three categories. The results indicate that the total percentage and surface fractal dimension of medium and large pores increase after freezingthawing, with the increase of permeability. Finally, a relationship between permeability and porestructure parameters has been proposed, which consists of small pores, and medium and large pores. The permeability for small pores is several orders of magnitudes lower than that of medium and large pores.