【摘要】：河岸邊坡的整體穩(wěn)定性計算,無法定量反映水位變化對邊坡各部位局部穩(wěn)定性的影響。基于點穩(wěn)定系數(shù)法與非飽和土力學理論,運用非飽和流固耦合模型進行河岸邊坡的穩(wěn)定性數(shù)值分析。以某大型模型試驗為例,通過繪制邊坡在水位升降作用下各時段所對應的點穩(wěn)定系數(shù)分布云圖,揭示邊坡的破壞原因與內(nèi)部穩(wěn)定性變化過程,并與實際觀測結(jié)果進行對比。研究表明:點穩(wěn)定系數(shù)法能合理地描述河岸邊坡各位置的穩(wěn)定性及其動態(tài)變化,與實際吻合良好;邊坡臨空面穩(wěn)定性較低,水位緩慢上升將導致有效應力降低及非飽和區(qū)基質(zhì)吸力喪失,易誘發(fā)淺層失穩(wěn);水位下降形成的動水壓力,是導致邊坡穩(wěn)定性下降的主因,坡腳處最易失穩(wěn),致使邊坡發(fā)生牽引破壞;邊坡內(nèi)部點穩(wěn)定系數(shù)隨水力梯度的增大而降低,非穩(wěn)定區(qū)分布面積隨水力梯度的增大而增大,并主要分布于浸潤線以下、坡腳以上。研究成果為此類邊坡的穩(wěn)定性評價及治理提供了一定的科學依據(jù)。
[Abstract]:The calculation of the whole stability of the riverbank slope can not quantitatively reflect the influence of the water level change on the local stability of the slope. Based on the point stability coefficient method and the theory of unsaturated soil mechanics, the numerical analysis of the stability of riverbank slope is carried out by using the unsaturated fluid-solid coupling model. Taking a large scale model test as an example, by drawing the cloud map of the point stability coefficient distribution corresponding to each period of time under the action of water level rise and fall, the failure cause and internal stability change process of the slope are revealed, and the results are compared with the actual observation results. The results show that the point stability coefficient method can reasonably describe the stability and dynamic change of riparian slope, which is in good agreement with the actual situation. The slow rise of water level will lead to the decrease of effective stress and the loss of matrix suction in unsaturated area, which will easily induce the shallow layer instability, the dynamic water pressure caused by the drop of water level is the main cause of the slope stability decline, and the slope foot is the most vulnerable to instability. The internal stability coefficient of slope decreases with the increase of hydraulic gradient, and the distribution area of unstabilized area increases with the increase of hydraulic gradient, and mainly distributes below the infiltration line and above the slope foot. The research results provide a scientific basis for the stability evaluation and treatment of this kind of slope.
【作者單位】： 中國地質(zhì)大學(武漢)教育部長江三峽庫區(qū)地質(zhì)災害研究中心;
【基金】：國家自然科學基金項目(41272309)
【分類號】：P642.2

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