降雨和水位变化条件下排涝河道岸坡稳定性的数值研究

Stability analysis of drainage channel slopes under rainfall and water level changes

为了研究降雨和水位变化对排涝河道岸坡稳定性的影响,结合温州市鹿城区丰门河的水文地质资料和现场取样试验结果,利用有限元软件建立河道岸坡的数值模型,计算分析在降雨和排涝过程中岸坡的稳定性变化规律。研究结果表明:当岸坡土体的渗透性较小且岸坡周围有建筑遮蔽时,降雨对岸坡渗流场的影响主要取决于降雨时间而非雨型,整个过程中岸坡并未发生大幅渗流,河道水位和河道周围的建筑是影响河道岸坡稳定性的主要原因。水位越高时的岸坡稳定性越大,建筑距离河道越近、荷载越大时,岸坡的稳定性越小。虽然密集分布的建筑会降低岸坡的稳定性,但同时也减小了岸坡稳定性对水位变化的敏感度。在所有工况下,丰门排涝河道岸坡的稳定安全系数均大于临界稳定安全系数1.20,说明当前的岸坡处于安全状态,无需额外支护措施。

To study the impact of rainfall and water level changes on the stability of drainage channel slopes,a numerical model was established using a finite element software,incorporating hydrogeological data and on-site sampling test results from the Fengmen River in Lucheng District,Wenzhou.The research findings indicate that the influence of rainfall on the slope’s seepage field primarily depends on the duration rather than the type of rainfall when there are adjacent buildings and the soil permeability of the slope is relatively low.Throughout the process,significant seepage did not occur in the slope.The water level in the channel and the adjacent buildings are the main factors affecting the stability of the slope.Higher water levels contribute to higher slope stability,while closer proximity of buildings to the channel and larger loads have a negative effect on the stability.Although the dense distribution of buildings may decrease slope stability,it also reduces the sensitivity of slope stability to changes in water levels.In all operating conditions,the stable safety factor of the drainage channel slope is larger than the critical stable safety factor(1.20).This indicates that the current slope of the bank is in a safe state and no additional support measures are necessary.