线性剪切流作用下设置沉井施工期受力特性研究

Research on Mechanical Property of Open Caisson Directly Mounted on Pre-consolidated Seafloor/Riverbed Under Linear Shear Current Actions During Construction

为研究水流作用对设置沉井施工期受力特性的影响,采用线性剪切流模拟非均匀流,建立水流-圆形设置沉井相互作用模型,分析不同施工阶段圆形设置沉井与水流的相互作用情况,并与均匀流作用进行对比。结果表明:线性剪切流作用下圆形设置沉井水流力及水流力矩随流速的增加均呈平方关系。线性剪切流呈表面流速大、底层流速小的规律,对结构尾流区的涡漩有显著抑制作用,与均匀流作用相比,线性剪切流作用下结构受力偏小。随着沉井不断下沉,结构吃水深度增加,过水断面进一步压缩形成了绕流,引起局部压力及水流力成倍增加。

The impact of current actions on the mechanical property of the open caisson that is directly mounted on the pre-consolidated seafloor/riverbed during construction is the focus of this study.A current-circular open caisson interaction model was developed to analyze the interaction of the circular open caisson and the currents at the construction stage,in which the non-uniform currents were simulated using the linear shear currents.The results were compared with the simulation under uniform currents.It is concluded that under the action of linear shear current,the current forces and the force moments exhibit a quadratic relationship as the current velocity rises.The linear shear currents feature greater surface velocity and smaller bottom velocity,which significantly suppress the vortexes in the wake area of the structure.Compared with the action of uniform currents,the load bearing capacity of the structure weakens under the linear shear current action.As sinking,the draught of the caisson increases,the cross-section of the passing-through currents is further compressed to be circumfluence,which causes fold increase of local pressure and current forces.