摘要
针对竖向排水板中有效真空压力分布模式存在的争议,基于流体力学相关理论对真空度和负压概念加以分析,指出排水板中孔隙水压力的变化量便是有效真空压力大小。通过计算排水板中孔隙水的总势能,并利用水具有趋向于更低能量状态的趋势原理,分析了孔隙水的运动机制及流动全过程,进而得到有效真空压力变化规律。研究表明,排水板中有效真空压力变化规律与初始地下水位、膜下真空度及排水板变形量紧密相关;有效真空压力的简化分布模式为折线形,转折点在与初始地下水位线交汇处;在地下水位线以上时,有效真空压力变化大,衰减梯度达10 k Pam;在地下水位线以下时,有效真空压力基本保持不变;排水板变形量越大,排水阻力越大,如果出现折管现象,可能导致膜下真空压力无法向下传递。
Aiming at the argument of vacuum transmission in drain board under vacuum preloading, this paper analyzes the concept of vacuum and negative pore water pressure under the theory of fluid mechanics, and points out that the real reason of soft soil drainage and consolidation is the decrease of pore water pressure in the drain board. The total potential of pore water in the key position of drain board is calculated by the theory of fluid mechanics. Then the action mechanism and flow process of pore water pressure is analyzed based on the lowest energy principle. So the changing rules of pore water pressure in the drain board are obtained. The results show that： 1） the changing rules of pore water pressure in the drain board relates closely to the ground water level, vacuum degree under membrane and drainage board deformation; 2） in the drain board, the simplified distribution pattern of pore water pressure reduction is a broken line, and the line＇s turning point is located in the ground water level; 3） the pore water pressure reduction changes a lot above the ground water level, and the attenuation rate is l0 kPa/m. But the pore water pressure reduction remains unchanged below the ground water level; 4） the more deformation of drainage board occurs, the more resistance of drainage is. When the drain board breaks, the vacuum load under membrane can not transmit to the deep ground.
出处
《水运工程》
北大核心
2015年第7期161-166,共6页
Port & Waterway Engineering
基金
福建省科技计划重点项目(2012Y0020)
福建省科技计划重点项目(2013H0016)
关键词
真空预压
土水势
孔隙水压力
初始地下水位
排水板变形
vacuum preloading
soil water potential
pore water pressure
initial ground water level
deformation of drain board
