摘要
坡面水位下降会在土坡内部产生渗流,同时也会提升土体强度和有效应力水平,前者对土坡安全不利,而后者对土坡安全有利。在分析非饱和土质边坡稳定问题时,须同时考虑瞬态渗流和土体强度变化。这两个因素共同受到土体渗透系数、坡面水位降幅与水位降速的影响。有限元分析表明,土坡的瞬时安全系数在坡面降水位过程中呈先下降后上升的趋势。土坡的最危险状态出现在水位下降前期。水位下降速度越大,土坡最危险状态出现的时间越早,安全系数也越低,这一特点在渗透性差的土坡中尤为显著。渗透性差的土坡其最危险状态安全系数较小,恢复至初始安全系数时所需的时间也较长。根据土体的渗透性选择合理的水位降速区间可避免土坡的稳定性出现过大削弱。
Seepage flow is a negative factor to slope stability under surface water drawdown conditions,while the increase of the effective stress and strength induced by the water drawdown is positive to slope stability.Both of the negative and the positive factors should be considered in stability analysis of unsaturated soil slopes and both of them are influenced by soil permeability coefficient,range and speed of water drawdown.In this paper,finite element analysis was conducted and it showed that the slope safety factor initially decreased,and then increased in the process of water drawdown.The most dangerous status appeared in the early stage of water drawdown,and its appearance instant and the corresponding safety factor value were influenced by water drawdown speed,especially for the slopes with low permeability.A slope with lower permeability rendered a smaller minimum-value for the safety factor,and needed a longer time to recover its initial value.Sharp decrease of safety factor could be avoided by controlling water drawdown speed in a reasonable range according to different soil permeability coefficients.
作者
张涛
张慧
黄文雄
ZHANG Tao;ZHANG Hui;HUANG Wenxiong(College of Mechanics and Materials,Hohai University,Nanjing 211100,P.R.China)
出处
《重庆大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2020年第6期12-20,共9页
Journal of Chongqing University
基金
国家自然科学基金资助项目(11772117)
江苏省普通高校研究生科研创新计划资助项目(KYLX15_0485)。
