海底盾构隧道管片上浮分析及控制研究

Floating Analysis and Control of Subsea Shield Tunnel Segment

为研究海底盾构隧道中管片的上浮机理及控制方法,以厦门地铁2号线海底盾构段为依托,采用数值模拟方法,首先分析注浆压力、初凝时间等对管片上浮量的影响,并提出相应的上浮控制措施;然后,建立三维管片模型,对注浆压力作用下,上浮量和管片错动及螺栓的内力进行分析计算;最后,结合现场实测数据予以分析。结果表明:注浆压力越大,管片底部上浮量越大;软土与硬土条件下相比,管片上浮量下降43.8%;沿管片周边不同部位设置不同的注浆压力,提高浆液早期刚度,能显著降低管片上浮量,注浆材料的刚度比E1/E28从0.6提高到0.8时,管片上浮量降低37.99%,最大弯矩降低43.27%;结合实测土压力与计算值表明,基于黏弹塑性流变模型(shotcrete混凝土本构)的海底盾构隧道模拟方法,能较合理地预测管片外土压力主要区段的量值和衰减规律。研究成果可为管片结构设计提供更加合理的依据。

In order to study the floating mechanism and control method of subsea shield tunnel segment,based on the subsea shield section of Xiamen Metro Line 2,the numerical simulation method is adopted.Firstly,the influence of grouting pressure and initial setting time on the floating amount of segment was analyzed,and the corresponding floating control measures were proposed.Then,a three-dimensional segment model was established to analyze the floating amount and segment dislocation under the effect of grouting pressure.The internal force of the bolt was analyzed and calculated.Finally,the field measured data were analyzed.The results show that:the greater the grouting pressure is,the greater the floating amount of segment bottom is;the floating amount of segment in soft soil is 43.8%lower than that in hard soil;setting different grouting pressure along different parts of segment periphery to improve the early stiffness of slurry can significantly reduce the floating amount of segment;when the stiffness ratio of grouting material E1/E28 is increased from 0.6 to 0.8,the floating amount of segment is reduced by 37.99%,and the maximum bending moment is reduced by 43%27%;finally,combined with the measured earth pressure and the calculated value,it shows that the simulation method based on the viscoelastic plastic rheological model(shotcrete concrete constitutive model)can reasonably predict the magnitude and attenuation law of the main sections of the earth pressure outside the segment.The research results can provide more reasonable suggestions for segment structure design.