摘要
含预切空腔的轮廓爆破技术被认为是改善高地应力下隧道轮廓成型的有效方法。然而,对这种爆破技术在不同地应力下性能的研究较少。本文通过校验后的公路隧道数值模型,调查了含预切空腔(PC)的两种典型轮廓爆破技术(即光面爆破(SB)和预裂爆破(PB))在不同地应力条件下的性能。结果表明,在耦合装药和50 MP地应力下,PCSB比PCPB能获得更好的隧道轮廓成型效果。此外,研究了两种轮廓爆破技术在不同的不耦合系数和地应力条件下的性能,发现随着地应力从30 MPa增加至50 MPa,PCSB和PCPB作用下隧道轮廓成型效果均逐渐改善。此外,在不同地应力条件下调整周边孔的不耦合系数能使PCPB形成有效的隧道轮廓。然而,对于PCSB,在不同地应力条件下,需调整所有炮孔的不耦合系数才能形成符合要求的隧道轮廓。最后通过多元非线性回归获得经验公式,本研究可以为不同地应力下使用PCSB和PCPB开挖隧道提供设计参考。
Contour blasting techniques with pre-cutting areas are deemed as promising methods to improve the contour quality of tunnel with high in-situ stress.However,their performance under different in-situ stresses has not been well studied.In this paper,the performance of two typical contour blasting techniques,i.e.,smooth blasting(SB)and presplitting blasting(PB)with pre-cutting(PC)areas(namely PCSB and PCPB)under different ground stress conditions is investigated by the road tunnel numerical model after calibration.The results show that under the coupled charge and 50 MPa in-situ stress,PCSB can form a better tunnel contour than PCPB.In addition,the performance of two techniques is investigated with different decoupled charge coefficients and in-situ stresses.It can be found that the contour quality under the PCSB and PCPB both gradually improves with increased in-situ stresses from 30 to 50 MPa.Moreover,adjusting decoupled charge coefficients of peripheral boreholes is feasible for the PCPB to form effective tunnel contour under different in-situ stresses.However,it is more appropriate to adjust decoupled charge coefficients of all boreholes for the PCSB to form eligible tunnel contours under different in-situ stresses.Empirical formulae are finally given to provide design guides of PCSB and PCPB to excavate different in-situ stresses of rock mass used in this paper.
作者
周子龙
王培宇
程瑞山
陈翠刚
蔡鑫
ZHOU Zi-long;WANG Pei-yu;CHENG Rui-shan;CHEN Cui-gang;CAI Xin(School of Resources and Safety Engineering,Central South University,Changsha 410083,China;Center for Infrastructural Monitoring and Protection,School of Civil and Mechanical Engineering,Curtin University,Bentley 6102,Australia)
基金
Project(2022YFC2903901)supported by the National Key R&D Project of China
Projects(52274249,52334003)supported by the National Natural Science Foundation of China
Project(2020-24)supported by the Key Science and Technology Project of Guangxi Transportation Industry,China
Project(2023ZZTS0516)supported by the Fundamental Research Funds for the Central Universities,China。
关键词
地应力
光面爆破
预裂爆破
隧道轮廓成型
不耦合系数
in-situ stress
smooth blasting
pre-splitting blasting
tunnel contour quality
decoupled charge coefficient
作者简介
Corresponding author:CHENG Rui-shan,PhD,Research Associate,E-mail:chengruishan@gmail.com,ORCID:https://orcid.org/0000-0002-7595-0428。
