岩土工程学报Issue(6)：1093-1104,12.DOI:10.11779/CJGE201506016
地铁列车振动荷载对穿越泥水盾构泥膜渗透系数的影响
Change ofhydraulic conductivity of filter cake caused by train vibration load of a running subway
摘要
Abstract
The pressure of filter cake declines because of the generation of the excess pore pressure caused by the train vibration load of a running subway when a slurry shield crosses the subway. The hydraulic conductivity amplification of the filter cake on account of its swelling due to the reduction of the pressure brings negative impact on the stability of excavation face. The effect of the running subway train vibration load on the generation of excess pore pressure in three categories of sand specimens is investigated through dynamic triaxial tests. The findings from these tests are used to predict the change of the hydraulic conductivity of filter cake via the improved Kozeny-Carman formula. It is concluded that the relationship between the maximum excess pore pressure and the amplitude of train vibration load can be described as an exponential function, and the maximum dynamic excess pore pressure ratio when the sand void is determined by the void between coarse particles is 50% of that when it is determined by the void between fine particles. The amplitude of train vibration load has no significant influence on the maximum dynamic excess pore pressure ratio when the dynamic stress ratio is not more than 0.15. Moreover, the effect of sand relative density on the maximum excess pore pressure is not evident. The rise of the maximum excess pore pressure in sand is the same when the decline of vertical stress is half of that of horizontal stress. The vibration load makes the hydraulic conductivity of filter cake increase 15 times in most cases, however, it will not rise to be too large and permeable if the hydraulic conductivity of filter cake is less than 7.73×10-8 cm/s.关键词
泥水盾构/下穿越/列车振动荷载/饱和砂土/动三轴试验/泥膜/渗透系数Key words
slurry shield/lower-crossing/train vibration load/saturated sandy soil/dynamic triaxial test/filter cake/hydraulic conductivity分类
建筑与水利引用本文复制引用
武军,廖少明,霍晓波..地铁列车振动荷载对穿越泥水盾构泥膜渗透系数的影响[J].岩土工程学报,2015,(6):1093-1104,12.基金项目
国家自然科学基金项目（51078292，51378389) （）
