No fragile-to-strong crossover in LiCl-H2O solution
Dynamics of water, especially in the temperature range of the “no man's land”, remain a mystery. We present detailed study of dynamics in aqueous LiCl solution that is often considered as a model for bulk water. We employ broadband dielectric and light scattering spectroscopy in a broad frequency and temperature range. Our analysis reveals no sign of the fragile-to-strong crossover (FSC) neither in structural relaxation nor in translational motions. Our experimental results combined with a large selection of literature data lead to the clear conclusion–there is no FSC in dynamics of aqueous solutions at T ∼ 200–230 K. Instead, our analysis reveals appearance of the so-called excess wing at the high frequency tail of the structural relaxation peak. We discuss the localized nature of the relaxation process that contributes to the excess wing.
Based on the field settlement monitoring data in the construction of Hangzhou Qingchun Road river-crossing tunnel,settlements of the embankment induced by two shields respectively were compared.Results showed that the settlements of the embankment induced by the shield on west line were larger than those on east line,which was due to sustained rainfall,severe fluctuation of chamber pressures,lack of construction experience and worse control of shielding parameters on the west line.Peck equation's applicability was evaluated,and the value range of the transverse settlement tough-width parameters and the soil loss ratio in this project were suggested.Considering the successful experience of crossing the embankment by these tunnels,some practical and effective measures are suggested for slurry shield to traverse the embankment.These results would provide a scientific basis for the design and construction of similar shield tunnels.