深埋大变形隧道炭质板岩蠕变特性试验  

Experiment of Creep Characteristics of Carbonaceous Slate of Deep-buried Tunnel with Large Deformation

作　　者：王更峰[1] 张永兴[1] 熊晓晖[1] 黄达[1] 

机构地区：[1]重庆大学土木工程学院,重庆400030

出　　处：《公路交通科技》2012年第9期95-102,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(41172243);长江学者和创新团队发展计划项目(PCSIRT)

摘　　要：针对深埋隧道中厚层炭质板岩蠕变特性,进行三轴压缩强度试验与三轴蠕变试验,建立能反映时间损伤的炭质板岩蠕变模型,进而为后续的深埋隧道时空效应分析提供蠕变模型与参数。结果表明,炭质板岩峰值强度较高,峰后出现应变软化,破坏时出现明显剪切破裂面。蠕变试验显示,随着加载应力水平提高,轴向与侧向均出现衰减蠕变、稳态蠕变及加速蠕变,侧向与轴向应变之间的关系由近似线性增加趋于破坏应力水平时的非线性增加。轴向蠕变存在起始应力阈值,约为同围压下瞬时抗压强度的60%,侧向蠕变起始应力阈值约为轴向的50%,侧向加速蠕变比轴向加速蠕变发生略早。在Burgers模型中引入反映力学参数随时间损伤劣化的损伤因子,建立了变参数Burgers蠕变损伤模型,损伤蠕变模型对试验数据的拟合效果优于定常Burgers模型。将变参数Burgers蠕变损伤模型串联一个由非线性黏壶与塑性元件并联而成的非线性粘塑性体,建立了非线性粘弹塑性蠕变损伤模型,该模型较好的描述了炭质板岩的加速蠕变,可用于后续的隧道大变形时空效应分析。According to the creep characteristics of middle thickness layer carbonaceous slate in deep buried tunnel, the triaxial compress strength test and triaxial creep test were carried out. The carbonaceous slate creep model for reflecting time damage was established, it can provide creep model and parameters for time - space effect analysis of the deep buried tunnel. The results show that the peak strength of carbonaceous slate was higher, the strain softening happened after peak strength, and appeared evident shear failure plane. The creep result shows that （1） with the increase of loading stress level, axial and lateral attenuation creep, steady creep and accelerated creep all appeared, and the relation between lateral strain and axial strain changed from approximate linear increase to nonlinear increase in failure stress level; （2） axial creep had starting stress threshold whose value was about 60% of the instantaneous compressive strength under the same confining pressure, the lateral starting creep stress threshold is about 50% of the axial threshold, and the lateral accelerated creep happened early than the axial accelerated creep. Then, the damage factor for reflecting mechanical parameters damage degrading with creep time was introduced into Burgers model, and the variable parameter Burgers creep damage model was established, whose fitting effect of test data was better than that of Burgers model. By connecting the variable parameter Burgers creep damage model with a nonlinear viscoplastic body which consisted of a nonlinear viscous component parallel connected with a plastic component, the nonlinear viscoelastic-plastic creep damage describe the accelerated creep of carbonaceous slate and can with large deformation.

关 键 词：隧道工程 深埋隧道 Burgers损伤蠕变 炭质板岩 蠕变特性 非线性黏弹塑性蠕变模型 

分 类 号：U451.1[建筑科学—桥梁与隧道工程] U456.1[交通运输工程—道路与铁道工程]