摘要
在隧道爆破开挖的过程中,地应力和节理对岩体爆破效果的影响显著,是隧道爆破孔网布设必须考虑的两个重要因素。为了确定地应力和节理共同作用时隧道周边孔孔网布设参数,以铜安高速巴岳山隧道为工程背景,通过现场钻芯取样,开展室内试验,获取了节理板岩的静动力学参数。基于LS-PREPOST软件,建立了不同地应力作用下节理岩体隧道爆破的三维数值分析模型,分析了地应力为3 MPa、6 MPa和9 MPa时节理岩体隧道爆破后不同位置的有效应力分布规律。提出了不同地应力作用下含节理岩体隧道爆破的孔网布设方法,并基于现场爆破试验进行了方法验证。结果表明:地应力对节理岩体隧道爆破时的裂纹扩展具有抑制作用,地应力越大,抑制效果越明显。爆炸应力波会在节理位置发生多次折、反射,导致超挖现象严重。Ⅳ级围岩研究段的周边孔孔距设置为45 cm、线装药密度设置为0.375 kg/m时,平均超挖值控制在20 cm内。研究段混凝土设计值为15.1 m^(3),3次现场试验的实际混凝土用量为26.4 m^(3)、23.7 m^(3)、25.8 m^(3),平均混凝土超耗量为10.2 m^(3),平均超耗率为67.5%,超耗率均控制在100%以内,爆破效果较优。
In the process of tunnel blasting excavation,the influence of ground stress and joints on the blasting effect of rock mass is significant,and they are two important factors that must be considered in the layout of tunnel blasting holes.The static and dynamic mechanical parameters of jointed slate were obtained by indoor experiments by taking the Tongan Expressway Bayue Mountain Tunnel as the engineering background.Based on the LS-PREPOST software,a three-dimensional numerical model of jointed rock mass tunnel blasting under different ground stresses(3 MPa,6 MPa,and 9 MPa)was established to analyze the distribution of effective stress at different locations after blasting.A method for the layout of blasting hole network in jointed rock mass tunnel under different ground stresses was proposed,and the method was verified based on on-site blasting experiments.The results show that ground stress has a restraining effect on crack propagation during jointed rock mass tunnel blasting,and the greater the ground stress,the more obvious the restraining effect.The explosion stress wave will undergo multiple refractions and reflections at the joint location,leading to serious over-excavation.When the hole spacing of the contour holes in the grade IV rock mass was set to 45 cm and the linear charge density was set to 0.375 kg/m,the average over-excavation value was controlled within 20 cm.The designed concrete volume of the research section was 15.1 m^(3),and the actual concrete consumption in the three on-site tests was 26.4 m^(3),23.7 m^(3),and 25.8 m^(3),with an average concrete excess consumption of 10.2 m^(3) and an average excess consumption rate of 67.5%,which were all controlled within 100%.
作者
李国庆
陶铁军
刘霞
田兴朝
谢财进
简兵希
LI Guo-qing;TAO Tie-jun;LIU Xia;TIAN Xing-chao;XIE Cai-jin;JIAN Bing-xi(School of Civil Engineering,Guizhou University,Guiyang 550025,China;School of Mining,Guizhou University,Guiyang 550025,China)
出处
《爆破》
CSCD
北大核心
2023年第3期59-67,共9页
Blasting
基金
国家自然科学基金地区科学基金项目(52064008)
贵州省高层次创新型人才(百层次)(黔科合平台人才-GCC[2022]004-1)。
关键词
地应力
节理岩体
三维数值分析
有效应力
超欠挖
ground stress
jointed rock mass
three-dimensional numerical analysis
effective stress
over-under excavation
