基于改进灰色关联度法对超小净距交叉隧道爆破施工研究

Study on Blasting Construction of Super-closely-spaced Cross Tunnel Based on Improved Grey Relational Analysis

在超小净距交叉隧道爆破施工时,对既有隧道扰动大,而且损伤是不可逆的,施工风险极大。因此十分有必要对超小净距交叉隧道爆破施工进行研究。文章以围岩等级、炸药量、净距和交叉角度作为影响因素进行探讨,并提出符合超小净距交叉隧道爆破的控制标准。研究结果表明:(1)对超小净距交叉隧道爆破影响最大是炸药量和净距,其次是围岩等级,最后是交叉角度;(2)当净距小于2D时,净距对既有隧道影响最大,当净距大于2D时,炸药量对既有隧道影响最大;(3)超小净距交叉隧道爆破施工的控制标准为振速和既有隧道衬砌变形,其中振速控制标准为1.73 cm/s,既有隧道衬砌变形控制标准为1.12 mm。

The blasting construction of a super-closely-spaced cross tunnel may pose disturbance to the existing tunnel,of which the damage is irreversible and the construction risk is great.So,it is very necessary to study the blasting construction of a super-closely-spaced cross tunnel.In this paper,the influencing factors of surrounding rock grade,explosive charge,spacing and intersection angle were investigated to put forward the control standards for blasting in the super-closely-spaced cross tunnel.The results indicate that:(1)the maximum influence on the blasting in the super-closely-spaced cross tunnel is explosive charge and spacing,followed by surrounding rock grade and finally crossing angle;(2)the spacing has the greatest impact on the existing tunnel when it is less than2 D and the explosive charge has the greatest impact on the existing tunnel when the spacing is greater than 2 D;(3)the control standards for blasting construction of the super-closely-spaced cross tunnel were vibration speed and deformation of existing tunnel lining,of which the control standard for vibration speed is 1.73 cm/s and that for deformation of existing tunnel lining is 1.12 mm.