Study On The Smooth Blasting Technology Of Weak-vibration In Tunnel

Smooth blasting as a controlled blasting technology to make the regular and smooth contoar,it used in all kinds of Geotechnical Engineering.Blasting vibration is a secondary hazard which can not be avoided in the process of blasting construction,it cause the surrounding rock to loosening and fall off.Especially in bad geological condition,it can cause collapse and brought serious hidden danger to excavation construction.In this paper,we use theoretical analysis and engineering experiment to analysis the influencing factors of blasting vibration in the tunnel excavation.Then implementation control improvement in cutting hole,blasting parameters and Hydraulic blasting on the basis.Finally,applying the finite element software ANSYS/LS-DYNA to analysis the blasting process.Further study on the vibration regularity of smooth blasting in tunnels.And provide evidence for guiding blasting construction with safety and fast.The principal results are as follows:(1)Under the Millisecond Blasting,the largest blasting velocity focus on the front blasting process.Especially the cutting hole,it's vibration size is twice as other hole.Therefore,focus on the cutting hole to make improvement is a effective method to reduce blasting vibration;(2)The excavation depth and the amount of single blasting explosive is the main factor of blasting.Under the premise of not affecting the progress of the construction,We can according to the actual surrounding rock condition,use the reasonable control of the excavation depth to control blasting vibration.On the other hand,under the condition of the amount of single blasting explosive,we can reducing the blasting vibration by increasing the number of holes in the larger section of the vibration,reducing the spacing of holes and reducing the amount of blasting explosive.In new technology,Hydraulic Blasting can reduce the concentration of dust and improve the fargmentation degress of the rock,it also has a good effect to reducing blasting vibration,through the experimental study it can make 10% to reduce.(3)In Smooth Blasting,the intensity of blasting vibration has a direct relationship with geological conditions,position of the hole,distribution of the exlosive and the method of blasting.When conteol the main influencing factors,wo should also combined with other methods to make one by one to optimize,only through this,we can get the best practical results.Therefor,analysis the effect of blasting vibration withqualitative and quantitative,at the same time,improve the blasting schemeand by dynamic improvement and Digital monitoring have a important practical significance to promote the improvement of controlled blasting technology,prevent geological disasters and ensure construction safety.