摘要
为反映寒区遭受冻融的岩石在外力作用下的应力-应变全过程,基于统计损伤力学理论,假设岩石微元体强度服从Weibull分布,结合最大拉应变破坏准则,建立了考虑冻融和荷载耦合作用的寒区冻融岩石损伤模型;推导了模型参数的理论解,利用已有的试验结果和已有损伤本构对模型进行了验证,探讨了不同冻融次数下岩石的总损伤曲线演化规律,并对模型参数进行了分析;采用数值模拟方法计算了冻融循环对隧道工程稳定性的影响.结果表明:本文所建立的模型可较好地重现岩石的应力-应变全过程,并能反映岩石的峰后强度;不同冻融次数下岩石的总损伤演变曲线呈“S”形,总损伤演变曲线可分为3个阶段,即初始损伤阶段、加速阶段和完全损伤阶段;Weibull分布参数m和f_(0)分别代表岩石的脆性特征和塑性特征;随着冻融次数的增加,隧道围岩的垂直位移、最大主应力及衬砌最大主应力均逐渐增加,但隧道围岩的应力增幅较小,经历10次冻融循环后,隧道拱顶的围岩下沉量和底部的围岩隆起量分别增加17.87%和19.24%,隧道围岩最大拉应力和压应力极值分别增加了2.70%和2.01%,隧道衬砌最大拉应力和压应力极值分别增加了21.52%和17.87%.
In order to reflect the whole process of stress-strain of rock subjected to freeze thawing in the cold region under external force,this paper uses the theory of statistical damage mechanics and assumes that the strength of rock microelements obeys Weibull distribution.Then,according to the maximum tensile strain failure criterion,a damage model of rock subjected to freeze thawing in the cold region is established by considering the coupling effect of freeze thawing and load.The theoretical solution of the model parameters is deduced,and the damage model is verified by the test results and damage constitutive model of the predecessors.The evolution law of the total damage curve of the rock under different freeze-thaw cycles is discussed,and the model parameters are analyzed.Finally,the influence of the freeze-thaw cycle on the stability of tunnel engineering is calculated by the numerical simulation method.The results show that the model established in this paper can well reproduce the stress-strain curve of the rock and reflect the post-peak strength of the rock.The total damage evolution curve of the rock under different freeze-thaw cycles is S-shaped,and it can be divided into three stages:initial damage stage,accelerated stage,and complete damage stage.Weibull distribution parameters m and f_(0) represent the brittle and plastic characteristics of rock,respectively.Additionally,with the increase in freeze-thaw cycles,the vertical displacement and the maximum principal stress of the tunnel surrounding rock increase.Meanwhile,the maximum principal stress of tunnel lining also increases.However,the stress of the tunnel surrounding rock increases slightly.After 10 freeze-thaw cycles,the settlement of surrounding rock at the top of the tunnel arch and the uplift of surrounding rock at the bottom increase by 17.87%and 19.24%,respectively;the maximum tensile stress and compressive stress extremes of the tunnel surrounding rock increase by 2.70%and 2.01%,respectively,while those of the tunnel lining increase by 21.52%
作者
候超
靳晓光
何杰
张驰
HOU Chao;JIN Xiaoguang;HE Jie;ZHANG Chi(School of Civil Engineering,Chongqing University,Chongqing 400044,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area,Chongqing University,Chongqing 400044,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China)
出处
《西南交通大学学报》
EI
CSCD
北大核心
2023年第5期1045-1055,共11页
Journal of Southwest Jiaotong University
基金
国家自然科学基金(51578091)。
关键词
岩石
冻融循环
破坏准则
损伤模型
参数分析
rock
freeze-thaw cycle
failure criteria
damage model
parameter analysis
