首穿黄河散粒体地层盾构管片力学行为研究

Research on the Mechanical Behavior of Shield Lining on Granular Soil across Yellow River

研究目的:兰州地铁1号线区间隧道首穿黄河散体状巨厚砂卵层,其面临高水压(0.4 MPa)、高渗透(62 m/d)、高强度(59~90 MPa)的工程地质问题。通过研制的具有水土压力独立加载功能的模型试验与数值试验对比研究,揭示变水头、不同侧压力系数、不同拼装形式下穿黄盾构管片内力特征分布规律,达到管片结构优化的目的,确保安全服役。研究结论:(1)球应力状态的水压力增加,对于改善管片内力分布具有积极意义;(2)定水头条件下,管片弯矩和偏心距随侧压力系数的增加而显著减小;(3)错缝拼装较通缝拼装在刚度、防水及受弯性能上具有明显优势,应以黄河低水位、错缝拼装组合为控制工况开展管片结构设计;(4)相关试验成果可为轨道交通领域盾构预制管片设计和施工提供借鉴。

Research purposes: During the tunnel construction of Lanzhou Metro Line 1 with the geological characteristics of high water press( 0. 4 MPa),high permeability( 62 m/d) and high intensity( 59 ~ 90 MPa),comparative study were done based on numerical and model experiment with loading function of water and soil pressure independently. On account of the above experiment,the law of lining internal force was revealed on the condition of different head,lateral pressure coefficient and assembling.Research conclusions:( 1) Incremental water pressure has a positive meaning for improving lining internal force distribution.( 2) Under the condition of constant head,bending moment and eccentricity significantly reduced with the increase of the lateral pressure coefficient.( 3) Contrast to straight assembling,staggered assembling has obvious advantages in the stiffness,waterproof and bending performance,so combination working condition with low water level of the Yellow river and staggered assembling should serve as a control condition.( 4) The related experiment results could provide reference for the design and construction of precast segment lining in the field of railway transit.