寒区隧道洞口仰拱混凝土早期开裂机理研究  

Cracking Mechanism of Fill Concrete at Entrance Section in Cold Region

作　　者：傅金阳[1,2] 赵宁宁 肖欧辉 刘任 阳军生 Fu Jinyang;Zhao Ningning;Xiao Ouhui;Liu Ren;Yan Junsheng(School of Civil Engineering,Central South University,Changsha 410075,P.R.China;National Engineering Laboratory of High Speed Railway Construction Technology,Changsha,410075,P.R.China;The 1st Construction Co.Ltd.,of China 16th Corporation,Beijing 101300,P.R.China)

机构地区：[1]中南大学土木工程学院,长沙410075 [2]高速铁路建造技术国家工程实验室,长沙410075 [3]中铁十六局集团第一工程有限公司,北京101300

出　　处：《地下空间与工程学报》2021年第4期1298-1308,共11页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(52078495,U1934211);湖南省自然科学基金(2019JJ50747);湖南省水利科技重大项目(XSK J2018179-01)。

摘　　要：结合数值模拟与对寒区隧道洞口段仰拱填充混凝土早期变形与开裂特征进行了研究。通过ABAQUS平台编写混凝土早期水化热、早期力学性能、温度与湿度动态变化过程子程序,并结合XFEM模拟了混凝土多场耦合作用下裂缝萌生与扩展过程。与某寒区隧道工程仰拱填充混凝土开裂情况进行了对比验证,结果表明:温湿变化耦合作用数值模型可以较好地反映混凝土早龄期温度变化趋势和表面裂缝扩展特征;负温环境和温度应力是其表面开裂的主要原因,既有混凝土和厚度较大处更严重;降低混凝土出罐温度、提高混凝土养护温度可有效避免寒区隧道施工仰拱填充混凝土早龄期表面开裂。Early deformation and cracking characteristics of fill concrete of tunnel invert at entrance section in cold region were studied by numerical simulation and field measurements. Based on the user development function of ABAQUS,four subroutines were coded to reflect the dynamic change process of early hydration heat,early mechanical properties,temperature and humidity of concrete in cold region. Then crack initiation and propagation process of concrete under multi-field were simulated by the extended finite element method(XFEM). Finally,the results were compared and validated with the cracking process of concrete at entrance section in cold region. The results show that the multi-field coupling numerical model presented in this paper can well reflect the temperature variation trend and surface crack propagation characteristics of concrete. Subzero Negative temperature and temperature stress during concrete hardening are the main causes of surface cracking. More serious cracking occurs at thicker concrete part or part closer to the existing concrete due to its deformation constrains. The surface crack distribution can be highly reduced by a higher ambient temperature. When low ambient temperature is inevitable,reducing the concrete tank temperature and increasing the concrete curing temperature can effectively avoid the early age surface cracking of filling concrete of tunnel invert at entrance section in cold region.

关 键 词：寒区隧道 开裂机理 多场耦合 开裂控制 

分 类 号：U455.91[建筑科学—桥梁与隧道工程]