大型干坞放排水过程中边坡稳定性分析

Analysis on Stability of Side Slopes of Large Dry Docks during Water Filling and Water Discharging

为研究复杂工况下干坞放排水过程中边坡的稳定性,以生物岛——大学城隧道工程为例,利用ANSYS计算软件进行数值模拟,同时结合现场监测数据,以修正理论计算方法,得出如下结论:1)干坞放、排水2个阶段,边坡几乎同时完成对水的"吸、吐"过程。"吸水"过程中边坡变形大于"吐水"过程中边坡的变形,并且边坡的"吸水"速率大于"吐水"速率,由于边坡持水能力,造成边坡内外水差局部最大达4m,对边坡稳定造成威胁;2)在控制边坡滑动时锚杆、锚索可以被动的发挥作用,而控制边坡的变形则十分有限;3)锚杆、锚索提高了潜在滑动面土体的整体性及强度,也使边坡土体内部刚度不连续,致使局部出现较大的屈服应力和变形;4)边坡两翼历史累积变形大于边坡中部。在边坡内外水作用下,由于边坡两翼约束方式不同,使之因"吸吐"水产生的变形也有差异。

Numerical simulation is made by means of ANSYS software and field monitoring data is used to modify the theoretical methods,so as to study the stability of the side slopes of large dry docks during water filling and water discharging under complex conditions.Conclusions drawn are as follows： 1） The course of the water absorption and water drainage of the side slopes are completed almost at the same time with the water filling and water discharging.The deformation of the side slopes in the water absorption period is larger than that in the water drainage period,and the water absorption velocity of the side slopes is larger than than of the water drainage velocity.Due to the water containing capability of the side slopes,the maximum difference between that of the water head in the side slope and that in the foundation pit at local positions reaches 4m,which jeopardizes the stability of the side slopes;2） While anchor bolts and anchor cables can play a passive role in the control of the slope slide,they can play little role in the control of the deformation of the slopes;3） While anchor bolts and anchor cables can improve the integrity and strength of the soil mass of the potential slide plane,they can make the internal rigidity of the soil mass of the slopes discontinuous and can induce large yielding stress and deformation at local positions;4） The accumulative deformation at both wings of the slopes are larger than that at the central point of the slopes.Under the action of the water heads inside the slopes and outside the slopes,the deformation at both wings of the slopes induced by water absorption and water drainage is different,due to the different restraining means at both wings.