Frost heaving and crack initiation characteristics of tunnel rock mass in cold regions under low-temperature degradation  

作　　者：CHEN Wenhua XIANG Tian 

机构地区：[1]School of Civil Engineering,Beijing Jiaotong University,Beijing 202303,China

出　　处：《Journal of Mountain Science》2024年第8期2844-2854,共11页山地科学学报（英文）

基　　金：This study was funded by the National Natural Science Foundation of China(No.51978039).

摘　　要：Water freezing in rock fractures causes volumetric expansion and fracture development through frost heaving.This study introduces a novel analytical model to investigate how uneven freezing force and surrounding rock pressure influence fracture initiation,based on mass conservation,elasticity,and water-ice phase transition principles.A model for rock fracture initiation considering freezing temperature,uneven freezing expansion,in-situ stress,and lateral pressure was proposed based on fracture mechanics.Equations for stress intensity factors were developed and validated using the phase field method.The effects of rock elastic modulus anisotropy and critical fracture energy density on fracture initiation were also discussed.The results show that the values of KI and KII exhibit an upward trend as the freezing temperature,uneven expansion,in-situ stress,and lateral pressure increase.The uneven freezing expansion has the most significant influence on KI and KII values among these parameters.As the uneven freezing expansion coefficient increases to 0.5,the fracture initiation mode shifts from tensile fracture to shear fracture.As the lateral pressure coefficient increases to 1,the fracture initiation mode shifts from tensile fracture to shear fracture.Rock elastic modulus anisotropy causes fractures to propagate in a clockwise direction,forming a'butterfly'pattern.Critical fracture energy density an isotropy causes counterclockwise deviation in propagation direction,resulting in branching paths and an'H'-shaped pattern.

关 键 词：Rock fractures Fracture water Uneven freezing expansion Phase field method Initiation angle ANISOTROPY 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]