大型钢吊箱封底混凝土与钢护筒共同作用研究

通过监测钢护筒和混凝土的应变，换算封底混凝土与钢护筒接触面的黏结强度，同时观测封底混凝土与钢护筒的相对位移，用于反演封底混凝土和钢护筒接触面的计算参数，进而反馈于封底混凝土与钢护筒共同作用的三维数值模拟计算分析，以获得封底混凝土与钢护筒接触面的平均极限摩擦强度．试验结果表明，在未浇注封底混凝土之前，观测期间承台混凝土发挥的最大握裹力为0．07MPa、数值模拟计算分析结果表明，在线性阶段封底混凝土与钢护筒接触面的平均单位摩阻力可达到0．28MPa．当平均单位摩阻力达到0．37MPa时，局部区域接触面达到屈服强度．

Study on coaction of subsealing concrete and steel pipe pile for large steel suspension-box cofferdam

The coaction of subsealing concrete and steel pipe pile is the key technology for design and construction of a large steel suspension-box cofferdam. The strain of steel pipe and subsealing concrete was converted into the bond strength of their contact surface in this test. By monitoring of the relative displacement of subsealing concrete and steel pipe, the calculation parameters of contact surface were back analyzed and then used for 3D numerical analysis of the coaction of subsealing concrete and steel pipe, so that the average ultimate frictional strength of the contact surface was educed. According to the monitoring results, the maximum bond strength of subsealing concrete was 0.07 MPa before placement of bearing subsealing concrete. The numerical analysis indicated that the average unit friction was 0.28 MPa at the elastic stage and the local contact surface came to yield when the average unit friction was 0.37 MPa.