大直径钢圆筒结构稳定性离心模型试验研究

Centrifugal model test on stability of large diameter steel cylinder structure

大直径钢圆筒结构是近年来兴起的一种新型水工结构形式,具有结构简单、施工速度快、结构受力条件好、造价低等优点,能够适应水深浪大的恶劣环境,在软土地区具有广阔的应用前景。在钢圆筒施工过程中,其在风浪荷载下的稳定性是工程关注的主要问题。以东海某码头工程钢圆筒护岸为研究对象,通过土工离心模型试验,研究钢圆筒结构的破坏模式和稳定性,并对位移、筒壁土压力、筒身应变等进行分析。结果表明:软土地基上钢圆筒结构在水平荷载作用下的失稳破坏模式主要表现为倾斜失稳,而不是整体平移;钢圆筒失稳破坏时的极限荷载约为其所受水平荷载的2倍;在水平荷载作用下,陆侧筒壁土压力逐渐升高,海侧筒壁土压力逐渐降低,陆侧筒壁土压力明显大于海侧;筒身应变随深度的增加而增大,钢圆筒底部的筒身应力明显大于上部。

The large diameter steel cylinder structure is a new type of hydraulic structure that has emerged in recent years.It has advantages of simple structure,fast construction speed,good structural stress conditions,low cost,and can adapt to the hostile environment of deep water and large waves,which has broad application prospects in soft soil areas.During the construction of steel cylinder,its stability under wind and wave load is the main issue of engineering concern.Taking the steel cylinder revetment of a wharf project in the East China Sea as the research object,we study the failure mode and stability of the steel cylinder structure through the geotechnical centrifugal model test,and analyze the characteristics of displacement,the cylinder wall soil pressure,cylinder body strain and etc.The results show that the failure mode of steel cylinder structure on soft soil foundation under horizontal load is mainly inclined failure,not overall translation.The ultimate load of the steel cylinder is about 2 times of the horizontal load when it loses stability and fails.Under the action of horizontal load,the soil pressure of the cylinder wall on the land side gradually increases,and the soil pressure of the cylinder wall on the sea side gradually decreases,and the soil pressure of the cylinder wall on the land side is significantly greater than that on the sea side.The strain of the cylinder increases with the depth,and the stress of the cylinder at the bottom of the steel cylinder is significantly greater than that at the top.