基于HSS本构模型的瓯江特大桥钢板桩围堰数值模拟

Hardening Soil Model with Small Strain Stiffness Based Numerical Simulation of Steel Sheet Pile Cofferdam of Ou River Specially Long Span Bridge

针对瓯江特大桥工程特点及地质条件,确定9#主墩承台施工的支护方案采用含二道内支撑的钢板桩围堰。基于小应变土体硬化模型(HSS模型),利用PLAXIS数值模拟软件建立了考虑河床在内的钢板桩围堰三维模型,对施工过程二种不同工况作了数值模拟,并与施工监测获得的围堰各构件应力进行了比较。结果表明:钢板桩围堰的刚度和强度均能满足要求,且围堰结构安全由钢板桩变形控制;数值模拟计算结果与现场实测数值较吻合,说明了可用HSS模型进行钢板桩围堰的设计优化。

The steel sheet pile cofferdam with two inner supports is determined to be adopted as the supporting scheme for construction of bearing platform of 9#main pier according to characteristics and geological conditions of the Ou River specially long span bridge. The PLAXIS numerical simulation software is utilized to establish the 3 D model of the steel sheet pile cofferdam by taking riverbed into consideration based on hardening soil model with small strain stiffness(HSS model), to conduct numerical simulation on two different working conditions during construction. In addition,comparisons are made on stress of various components of the cofferdam acquired from construction monitoring. According to the results,both the stiffness and the strength of the steel sheet pile cofferdam can meet related requirements,and the structure safety of the cofferdam is controlled by steel sheet pile deformation. The numerical simulation results are consistent with measured values,indicating that the HSS model can be adopted for design optimization of the steel sheet pile cofferdam.