苏通大桥主塔墩冲刷防护工程关键技术

Key techniques for scouring protection of the main pylon pier of Sutong Bridge

针对苏通大桥桥址处水深流急、河床易冲刷和大桥主墩桩基结构的特点,采用抛投袋装沙作预防护和运用下沉护坦原理作为冲刷防护设计理念,保证了群桩基础顺利施工,并使由于桥墩防护工程边缘遭破坏及河床深槽变化引起的边坡坍塌得到了有效防护.针对群桩墩处河床局部冲刷的复杂性,运用正态动床物理模型较好地预测了桥墩附近河床局部冲刷,并获得了现场监测结果的验证.通过在水流中现场抛投沙袋群体的试验,较好地解决了在易冲底床处大面积抛投防护材料的技术和施工工艺.在此基础上,提出了在苏通大桥主塔墩冲刷防护的验收计算模式.

According to the conditions of the Sutong Bridge, such as deep water, rapid flow, erodible riverbed and pile foundation of the pylon, the sand-filled bags and protection-apron are adopted in designing the scouring protection to ensure the construction of the pile foundation, and to protect effectively the slope failure caused by the failure at the edge of the protection works of the pier and the deep variation of the riverbed. According to the local scouring around the pile foundation of the pylon, a normal movable-bed physical model test is conducted to predict the local scouring and is verified by the field measured data. Based on the field throwing test of sand-filled bags, the techniques for throwing protective materials to the erodible river-bed are solved, and the acceptance calculation model for scouring protection at the pier foundation area of the Sutong Bridge is presented.