摘要
现行隧道设计规范未考虑浅埋黄土隧道常见的地表张拉裂缝对围岩压力的影响。文章首先总结了浅埋黄土隧道围岩变形特征和破坏滑移面组成特点,之后基于极限平衡理论构建围岩压力计算模型,推导了张拉裂缝开裂深度和隧道围岩压力计算公式,探讨了计算结果与影响参数之间的关系,最后通过与实测数据和现有理论计算结果对比,证实了计算方法的合理性。研究表明:由于地表张拉裂缝的存在,土体内倾斜剪切面上的正应力和切应力均较不考虑地表张拉裂缝时的大,破裂面分担更多上覆土体产生的荷载,浅埋黄土隧道围岩压力显著降低;新模型的围岩压力计算结果随埋深增加呈抛物线形式变化,其曲线峰值可为隧道深浅埋界定提供参考,与传统方法相比,新模型计算结果更接近实测值。
The influence of ground surface tension cracks on surrounding rock pressure of shallow-buried loess tunnels is not considered in the current tunnel design code.The paper first summarizes the deformation characteristics of surrounding rocks and the composition characteristics of failure slip plane in shallow-buried loess tunnels,then it constructs the calculation model of surrounding rock pressure based on the limit equilibrium theory,deduces the calculation formulas of tension cracking depth and tunnel surrounding rock pressure,and discusses the relationship between calculation results and influencing parameters,and finally,by comparing with the measured data and the existing theoretical calculation results,it proves the rationality of the calculation method.The research results show that due to the existence of ground surface tension cracks,both the normal stress and shear stress on the inclined shear plane in the soil mass would increase compared with that without considering surface tensile cracks,the fracture plane would share more loads generated by the overlying soil masses,and the surrounding rock pressure of the shallow-buried loess tunnel would be significantly reduced.The calculation curve of surrounding rock pressures in the proposed new model presents a form of parabola changing with the increase of buried depth,and the peak value of the curve can provide a reference for the demarcation of deep or shallow buried depth of a tunnel.Compared with the traditional methods,the calculation results of the new model are closer to the measured values.
作者
来弘鹏
王斌
刘禹阳
LAI Hongpeng;WANG Bin;LIU Yuyang(School of Highway,Chang′an University,Xi′an 710064;School of Civil Engineering,Chang′an University,Xi′an 710064)
出处
《现代隧道技术》
CSCD
北大核心
2021年第6期95-101,共7页
Modern Tunnelling Technology
基金
国家自然科学基金(51978064,51908051)
山西省交通科技项目(2018-1-3)
山西交通控股集团有限公司科技项目(2019-JKKJ-41).
关键词
黄土隧道
张拉裂缝
极限平衡
围岩压力
Loess tunnel
Tension crack
Limit equilibrium
Surrounding rock pressure
