超高性能混凝土加固盾构隧道结构试验与数值研究

Experimental and Numerical Study on Shield Tunnel Strengthened by Ultra-high Performance Concrete

摘要:

在应用超高性能混凝土（UHPC）加固既有盾构隧道的基础上，提出优化的钢板?UHPC组合加固方法。将钢板作为隧道内衬并在钢板与管片之间填充UHPC，采用植筋、化学锚栓以及栓钉等作为界面连接件，形成共同受力的整体。开展极限承载力足尺试验并建立非线性数值模型，探究组合加固结构的破坏机理以及影响受力性能的关键因素。结果表明，组合加固结构破坏模式具有较好的延性特征；组合加固结构刚度主要受管片及加固体刚度控制，承载力水平主要受管片强度控制，极限承载力相比UHPC加固结构提升28%；极限状态下，顶部和腰部等位置的钢板发生屈服、主筋受拉屈服。数值参数分析结果表明，组合加固结构性能指标受加固层厚度和界面黏结性能影响较大，可适当增大钢板厚度并保证界面连接件的数量。

Abstract:

Based on the application of ultra-high performance concrete （UHPC） in the shield tunnel strengthening， the steel plate-UHPC reinforced structure of shield tunnels was proposed. Steel plates were utilized as the inner linings of shield tunnels， with UHPC filling between steel plates and segments. Planting reinforcing bars， chemical anchors and struts served as the interface connectors， forming a community capable of withstanding external load. By conducting the full-scale ultimate load test and establishing the nonlinear numerical model， the failure mechanism of the reinforced structure was investigated， and key factors affecting the reinforcement performance were analyzed. The results indicate that the failure mode of the reinforced structure exhibits superior ductility characteristics. The stiffness of the reinforced structure is primarily dominated by the stiffness of the segments and the reinforcement， while the bearing capacity of the reinforced structure is crucially influenced by the strength of segements， and the ultimate bearing capacity increases by 28% compared to the structure only reinforced by UHPC. In the event of the limit state， a few steel plates located at the top and waist of the structure yield， with main reinforcements yielding in tension. The numerical parameter analysis demonstrates that the performance indexes of the reinforced structure are significantly influenced by the thickness of reinforcement layers and the bonding performance of interfaces. Consequently， it is recommended that the thickness of the steel plate be increased and that the interface connectors be secured.