博罗县河道清淤深度对岸堤变形及渗流影响分析

河道清淤能够提高河道防洪、排涝和灌溉能力，但由于施工扰动，部分清淤工程会引起河道岸坡应力调整、卸荷变形及损伤破坏，影响坡体安全和工程质量。本文以博罗县河道清淤项目为例，结合非饱和流固耦合理论，分析了清淤深度对岸坡滑动面、安全系数、塑性破坏以及监测点位移的影响。结果表明：随着清淤深度的增大，边坡的安全系数逐渐降低，当清淤深度为1.6m 时，安全系数为1.58，比原始岸坡降低了9.19%；清淤深度对边坡的塑性破坏有明显影响，当开挖到设计高度后，其坡角的塑变破坏范围约为临空面长度的1/3；随着开挖深度的增加，4 个边坡监测点的水平位移均呈增长趋势，但非线性特征明显，呈对数函数增长；随着开挖至最后阶段，岸堤内部的地下水向清淤方向流动，其中出口的流速最大。

英文摘要:

River dredging can improve the flood control，drainage and irrigation capacity of the river. However，due to construction disturbance，some dredging projects will cause stress adjustment，unloading deformation，and damage of the river bank slope，affecting the slope safety and project quality. Taking the river dredging project in Boluo county as an example，combined with the unsaturated fluid structure coupling theory，this paper analyzes the influence of dredging depth on bank slope sliding surface，safety factor，plastic failure and displacement of monitoring points. The results show that the larger the dredging depth is，the larger the landslide volume will be and the lower the safety factor of the slope will be. When the dredging depth is 1.6m，the safety factor is 1.58，which is 9.19% lower than the original bank slope；the depth of dredging has a significant impact on the plastic failure of the slope. When the excavation reaches the design height，the plastic deformation failure range of the slope angle is about 1/3 of the length of the free face；With the increase of excavation depth，the horizontal displacement of the four slope monitoring points shows an increasing trend，but the nonlinear characteristics are obvious，showing a logarithmic function growth；With the excavation until the final stage，the groundwater in the bank lift flows towards the dredging direction，and it flows most quickly at the outlet.

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