盾尾注浆材料硬化特性对隧道和地层力学响应影响的有限元模拟研究

Finite Element Method Simulation for the Influence of Hardening Characteristic of Grouting Materials at the Shield Tail on Mechanical Response of the Lining and Ground

为了探究注浆材料硬化和注浆压力的消散过程对软土地层和隧道衬砌受力变形的影响,以青岛某地铁隧道为背景,考虑盾构机与土体相互作用、衬砌-注浆层-土体相互作用,以及注浆材料硬化和注浆压力消散过程,基于ABAQUS有限元平台建立了盾构施工精细化的有限元数值仿真模型,并利用实测地层沉降和隧道衬砌的收敛变形验证了数值模型的合理性。同时,对注浆材料初凝时间分别为0、2、6、12 h的数值模型进行了计算,获得了地层和隧道衬砌受力变形随注浆材料硬化过程的发展规律,以及注浆材料硬化特性对地层和隧道衬砌受力变形的影响规律。模拟结果表明:盾尾注浆8 h以内,地层的沉降和水平位移以及隧道衬砌的围岩压力和内力增加显著,注浆时间超过8 h后增加变得缓慢;注浆材料的初凝时间越长,地表沉降、地层水平位移和竖向位移则越大;衬砌拱顶和拱腰的径向收敛越大,拱底径向收敛则越小;衬砌的轴力和弯矩在注浆8 h以内增加显著。

The filling of the grout in the shield tail clearance of the shield is a significant measure to ensure the construction quality of shield tunnel.The process of the pressure dissipates and material hardening of grouting have a great impact on the deformation and force of the soft soil layers and shield tunnel.However,the related researches focusing on this issue are rarely reported in the literature.By considering the interaction between shield machine and soil,the interaction between lining grouting layer and soil,as well as the hardening process of grouting materials and the dissipation process of grouting pressure,a finite element method(FEM)numerical simulation model of shield tunneling was conducted in this study.Based on a case of shield tunnel in Qingdao,this FEM model was verified by measured ground settlement and convergence deformation.To obtain the development principle of the deformation and force of the soil layers and shield tunnel due to the pressure dissipates and material hardening of grouting,the FEM numerical models without considering the hardening process of grouting materials and the initial solidified time of grouting materials being 2 hours,6 hours and 12 hours were calculated,respectively.The FEM results show that the settlement and horizontal displacement of the soil layers within 8 hours of grouting,and the surrounding earth pressure and internal force of the shield tunnel increase significantly,while increase slowly after the grouting time exceeds 8 h.