Study on influence of key blasthole parameters on tunnel overbreak  

作　　者：Zi-qiang Li Zheng Li Wei-wei Huang Xuan-ming Ding Hang Zhang 

机构地区：[1]School of Civil Engineering and Architecture,Chongqing University of Science&Technology,Chongqing 401331,China [2]Key Laboratory of New Technology for Construction of Cities in Mountain Area,Ministry of Education,Chongqing University,Chongqing 400045,China [3]Chongqing City Construction Investment(Group)Co.,Ltd.,Chongqing 400023,China [4]School of Civil Engineering,Chongqing University,400045,China

出　　处：《Underground Space》2023年第2期76-90,共15页地下空间（英文）

基　　金：supported by the Open-end Fund of Key Laboratory of New Technology for Construction of Cities in Mountain Area(LNTCCMA-20210108);the National Natural Science Foundation of China(5108098,51908387);the Chongqing Municipal Construction Investment(Group)Co.,Ltd.Joint Technical Issues(CQCT-JSA-GC-2021-0138);the Chongqing Natural Science Fund General Project(cstc2020jcyj-msxmX0904);the Chongqing Talents:Exceptional Young Talents Project(cstc2021ycjh-bgzxm0246);the China Postdoctoral Science Foundation-General Project(2021M693739);the Chongqing Outstanding Youth Science Fund Project(2022NSCQ-JQX1224);the Chongqing University of Science&Technology Graduate Innovation Program Project(YKJCX2120613);the Special Funding for Postdoctoral Research Projects in Chongqing(2021XM2019).

摘　　要：To determine the influence of key blasthole parameters on tunnel overbreak during blasting construction,an intelligent detection sys-tem for tunnel blasting construction is independently developed.And the key blasthole parameters and overbreak of a typical section of a single line tunnel under the condition of Class V surrounding rock are analyzed and detected.The actual data obtained is compared with the results of numerical simulations and theoretical calculations.The results are as follows:(1)Quantitative analysis is performed based on the blasthole angle,opening position,and charge mass by the self-developed intelligent detection equipment for blasthole parameters,which can be used to guide the drilling construction.Intelligent scanning equipment for outline excavation can be used to image the actual excavation section in real-time and has the advantages of high precision and fast speed;(2)Tunnel overbreak can be regarded as consisting of two parts:the surrounding rock damage caused by the blasting load,and the collapse of the surrounding rock caused by the blasthole opening position.Every parameter of the peripheral hole will affect the tunnel overbreak;however,the key parameter is the blasthole opening position;(3)The distributions of the tunnel overbreak volume obtained with the theoretical analysis,finite element simulation,and measurements are basically consistent.Under the condition of Class V surrounding rock,the overbreak of this single line tunnel can reach 14.1–78.2 cm.To meet the specification requirements,the opening position and construction accuracy of the peripheral hole should be strictly controlled.

关 键 词：Tunnel blasting Blasthole parameters Tunnel overbreak Surrounding rock damage Smooth surface blasting 

分 类 号：U45[建筑科学—桥梁与隧道工程]