泰州大桥悬索桥南锚碇基础的变形及超载安全度分析

 锚碇作为悬索桥的主要承力结构物,其变形是影响悬索桥安全的重要因素。针对泰州大桥悬索桥的南锚碇基础,建立了三维的地层-结构模型,应用大型数值软件Flac3D和超载分析法,假定锚碇的超载为大缆拉力按比例增加,研究了锚碇基础的变形随大缆拉力超载系数的变化规律。结果表明,在大缆拉力为设计载荷,即大缆拉力超载系数λ=1时,数值模拟计算结果与现场实测结果接近;在超载情况下,当λ<3.5时,锚碇基础最大变形随大缆拉力超载系数基本呈线性增加;当λ>3.5时,锚碇基础变形随大缆超载系数呈非线性增加;而当λ=3.81时,锚碇基础的水平位移达到极限值。因此,综合考虑锚碇基础的土体塑性区分布和变形控制要求,得到了泰州大桥悬索桥南锚碇基础的超载安全度为3.81的结论,可为泰州大桥工程的稳定性评价提供参考依据。

Deformation and Safety Analysis of Taizhou Suspension Bridge South-Anchor Foundation under Surcharge

The anchor foundation is the main bearing structure of suspension bridges and its deformation and stability are very important issues. For the south-anchor foundation of the Taizhou Bridge,the stratum and structure model of three-dimensional is established. Using large-scale numerical software Flac3D and surcharge analysis method, the deformations of the anchor foundation with different surcharge coefficients are studied based on the assumption that the values of surcharge are changed proportionally with the cables tension. The results show that the values of numerical simulation are close to the measured values under the design value of the cable tension. The linearly increasing relationship between the maximum deformation of anchorage foundation and value of the surcharge coefficient is obtained when the surcharge coefficient is less than 3.5. The nonlinearly increasing relationship between the maximum deformation of anchorage foundation and value of the surcharge coefficient is obtained when the surcharge coefficient is greater than 3.5. When the value of the surcharge coefficient is 3.81 times of the design value of the cables tension, the maximum horizontal displacement of the anchor foundation reaches the limit value. Based on the soil plastic zone distribution range and deformation control requirements of the anchorage foundation, the numerical value of surcharge safety for the south-anchor foundation of the Taizhou suspension bridge is 3.81. The reference conclusions for the stability evaluation of the Taizhou bridge project are provided.