摘要
蠕变是隧道施工期的典型变形特征.针对现有蠕变模型参数多的问题,结合铜万高速公路隧道施工期的蠕变特点,提出了改进的Kelvin三维蠕变模型,模型只有两个蠕变参数.基于改进蠕变模型的单轴压缩数值模拟结果表明:非破坏荷载下二云石英岩的轴向蠕变与室内试验结果拟合程度高,破坏荷载下的轴向蠕变相对误差在5%以内.在单轴压缩数值模拟的基础上开展了铜万高速公路狮子垴二号隧道三维蠕变数值模拟,由于隧道埋深小未出现屈服,只有减速蠕变和稳定蠕变两个阶段,瞬时弹性变形只有5.35 mm,当变形时间为10 h时,净蠕变量约为瞬时变形的48%,10h后的蠕变变形很小.由于蠕变工况下隧道变形大,围岩出现卸荷现象,蠕变工况下地表和开挖处附近的应力小于非蠕变工况下的对应值.研究结果对于隧道现场支护时机和方法的选择具有一定的指导意义.
Creep is a typical deformation characteristic during tunnel construction.Aiming at the problem that there are many parameters in the existing creep model,combined with the creep characteristics of Tongwan Expressway Tunnel in construction period,an improved Kelvin three-dimensional creep model is proposed.The model has only two creep parameters.The results of uniaxial compression numerical simulation based on the improved creep model show that the axial creep of dolomite quartzite under non-destructive load is in good agreement with the laboratory test results,and the relative error of axial creep under failure load is less than 5%.Based on the uniaxial compression numerical simulation,the three-dimensional creep numerical simulation of shizinao No.2 tunnel on Tongwan expressway is carried out.Due to the small buried depth of the tunnel,there are only two stages of deceleration creep and stable creep.The instantaneous elastic deformation is only 5.35 mm.When the deformation time is 10 h,the net creep deformation is about 48%of the instantaneous deformation,and the creep deformation after 10 h is very small.Due to the large deformation of the tunnel under creep condition,the unloading phenomenon occurs in the surrounding rock.The stress on the surface and near the excavation site under creep condition is less than the corresponding value under non creep condition.The research results have a certain guiding significance for the selection of tunnel support opportunity and method.
作者
黄红元
赵明阶
何昌春
HUANG Hong-yuan;ZHAO Ming-jie;HE Chang-chun(Hydraulic Structure Health Diagnosis Technology of Chongqing Jiaotong University,Chongqing University Engineering Research Center,Chongqing 400074,China;School of Civil and Architectural Engineering,East China University of Technology,Nanchang 330013,China)
出处
《数学的实践与认识》
2021年第9期145-153,共9页
Mathematics in Practice and Theory
关键词
隧道蠕变
二云石英岩
开尔文模型
数值模拟
单轴压缩
tunnel creep
dolomite quartzite
kelvin model
numerical simulation
uniaxial compression
