摘要
为解决溶洞与隧道间安全距离如何确定的问题,在研究现有动荷载下顶板安全厚度确定方法的基础上,推导出固支梁振动微分方程,建立隧道与溶洞间岩层失稳的双尖点突变模型,分析其失稳力学机制及破坏条件,得到安全厚度的非线性方程,并运用Matlab进行迭代法编程求解;分析爆破振动强度、频率、围岩特性、隧道跨度等对安全厚度的影响。结果表明:隧道与溶洞间岩层安全厚度是由岩层的内外因素共同决定;在同一振动荷载幅值下,安全厚度与振动频率呈非线性关系;在同一振动频率下,安全厚度与爆破振动荷载幅值呈线性关系;安全厚度随弹性模量的增加而逐渐减小,随溶洞跨度的增加呈近似正比例增加。
To solve the difficult problem of how to determine the safe distance between karst caves and tunnels,the vibration differential equation of fixed-supported beam was established on the basis of the study of the existing methods for determining the safe thickness of roofs under dynamic load,and the double cusp catastrophe model of rock stratum instability between tunnels and karst caves was deduced.Then,its instability mechanism and failure conditions were analyzed,the nonlinear equation of the safe thickness was obtained before Matlab programming-based iteration method was utilized to solve the equation.What’s more,analysis was also made on the impact of blasting vibration intensity,frequency,features of surrounding rocks and tunnel span on the safe thickness.It was found that the safe distance between tunnels and karst caves was determined by the internal and external factors of the rock strata;in addition,under the same amplitude of vibration load,the safe thickness has a nonlinear relationship with vibration frequency,while it has a linear relationship with blasting vibration amplitude when at the same vibration frequency;meanwhile,the safe thickness gradually decreases with the increase of elastic modulus,and was approximately proportional to increase along with the increase of the karst cave span.
作者
刘波
肖红飞
LIU Bo;XIAO Hongfei(Institute of Urban Construction and Enviroment,City College Dongguan University of Technology,Dongguan Guangdong 523419,China)
出处
《中国安全科学学报》
CAS
CSCD
北大核心
2019年第4期104-111,共8页
China Safety Science Journal
基金
东莞市社会科技发展项目(20185071511503)
东莞理工学院城市学院院级重大科研培育项目(2019YZD001Z)
关键词
隧道
溶洞
突变理论
失稳
顶板安全厚度
tunnel
karst cave
catastrophe theory
instability
safety thickness of roof
