盾构管片横向大变形TRC控制方法及作用机制研究

 为有效控制盾构管片的横向变形，分析盾构隧道的加固特点和常用内表面加固方法存在的不足，提出纤维编织网增强混凝土(textile-reinforced concrete，TRC)控制方法。建立TRC加固层及界面模拟方法，并利用试验结果验证该方法的合理性，进一步采用数值手段研究隧道横向变形和顶拱接头张开量在不同地层刚度系数、加固时机、纤维编织网用量和加固层布置范围下的响应规律。在此基础上，结合管片的变形和内力规律，揭示TRC控制管片横向变形的作用机制。研究表明：TRC能有效控制隧道横向变形和顶拱接头张开量，地层刚度系数越小，控制效果越优异；加固前隧道已有变形会造成纤维编织网产生损失应变，已有变形越小，损失应变越小，控制效果越好；纤维编织网用量提高，控制效果增强，但纤维编织网利用率降低，因此增强趋势减弱；TRC加固层合理布置范围建议在顶拱反弯点间的受拉部位，在该范围内，加固层越长，控制效果越好。研究结果丰富了管片内表面加固方法，深化了内表面加固机制的认识，可为工程实践提供理论指导和技术支持。

Control method and mechanism of large transverse deformation of shield segment using TRC

The strengthening characteristics and the shortcoming of the strengthening methods commonly used at the inner interface of the shield tunnel were analyzed and the textile reinforced concrete(TRC) was proposed to control the transverse deformation. The method of simulating the strengthened layer and interface was presented and validated by experiment. The responses of lateral deformation and joint opening at the top arch were analyzed with numerical analysis in terms of the stiffness coefficient of the formation，the timing of the strengthening construction，the amount of the textile and the arrangement of the reinforcement layer. The mechanism of TRC in controlling the transverse deformation of shield tunnel was revealed based on the analysis of deformation and internal force of the segment. The results of the research indicate that TRC can effectively restrict the horizontal convergence and joint opening. The reinforcement effect is better if the stiffness of ground layers are lower. The increasing in textile layers enhanced the control effect，however，the efficiency of fiber utilization was decreased. The reasonable layout of the strengthening layer was proposed to be set in the tension section of the arch between the inflection points. The longer the strengthening layer，the better the controlling effect.