Study on fractal dimensions of the silty soil around the tunnel under the subway loading in Shanghai

Based on the global digital systems, by fully considering the factors of the accumulated deformation, such as the frequency, the dynamic stress amplitude as well as the consolidation ratio, the mercury intrusion test was conducted to quantitatively study the microstructures of the silty soil around the tunnel near the Guoquan station of line No. 10 Subway in Shanghai. The thermodynamic model was used to calculate fractal dimensions in the analysis of the mercury intrusion data. The results show that the relationship of ln(W _n /r _n ² ) and lnQ _n was a significant linear correlation and the correlation coefficient is over 0.98. The relationship between the fractal dimensions and the frequency, the dynamic stress amplitude as well as the consolidation ratio was analyzed; the variation law of the residual strain with the fractal dimensions was obtained. The study offers the theoretical support for damage mechanics, the subway axial deformation and the ground settlement under the subway vibration loading.