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为探讨天然沉积硅藻土的微观结构及变形机制,对硅藻土样进行了SEM电镜扫描、压汞试验和高压三轴试验。采用图像分割原理及最佳阈值法分析了天然沉积硅藻土在不同固结压力下的分形特征和孔隙结构特征参数,探讨了硅藻土分形维数和各向等压固结压力之间的关系。结果表明,硅藻土体多孔隙,具有很强的结构性。土中孔隙孔径大多在0.1~1.0μm之间。在固结压力达到屈服压力后,孔径大于1μm的较大孔隙随固结压力的增加而减少,硅藻颗粒破坏,孔隙结构坍塌。获取了灰度阈值及二值化后的SEM图像。得到天然沉积硅藻土在不同固结压力下的分形盒子数和盒维数。结果还表明分形盒维数随固结压力增加而增加,天然沉积硅藻土在固结压力下的微观结构性及孔隙分布可通过分形盒维数来反映。
In order to investigate the microstructure and deformation mechanism of natural sedimentary diatomite, the SEM images of diatomite samples, mercury intrusion tests and high pressure triaxial tests were carried out. Fractal characteristics and pore structure parameters of natural sedimentary diatomite under different consolidation pressures were analyzed by using image segmentation principle and optimal threshold method. The relationship between the fractal dimension of diatomite and the isostatic pressure relationship. The results show that diatomite porous, has a strong structural. Soil pore size mostly in the 0.1 ~ 1.0μm between. After the consolidation pressure reaches the yield pressure, the larger pores with pore size larger than 1μm decrease with the increase of consolidation pressure, the diatom particles destroy and the pore structure collapses. Grayscale thresholds and binarized SEM images were obtained. The fractal box number and box dimension of natural sediment diatomite under different consolidation pressures were obtained. The results also show that fractal box dimension increases with increasing consolidation pressure. The microstructure and pore distribution of natural sedimentary diatomite under consolidation pressure can be reflected by the fractal box dimensions.