The Study Of Blasting Vibration Influence And Control Technology On Established Tunnels

With the rapid development of China's economy,the existing tunnel facilities plays an increasingly important role in transport infrastructure.A lot of new construction in the construction process,engineering blasting will produce more or less influence on safety stability of the existing tunnel.At present,study on the influence of blasting vibration on the existing tunnel structure is insufficient.Therefore,we carry out research on blasting vibration control of tunnel effect,the results of the study is the tunnel structure safety and stability,anti vibration and anti vibration damping measures and site safety coefficient.These results provide reference for tunnel design and safety evaluation.These studies have important significance in accelerating construction progress,improve safety and improve economic efficiency.In this paper,based on the classical stress wave analysis method,we carried out the influence of blasting vibration effect on tunnel stability analysis.At the same time,we established mathematical analysis model about the blasting vibration effect on tunnel,and obtained concrete ultimate tensile and shear safety vibration velocity of P wave and S wave.By the method of limit analysis,first of all,the author replace the blasting dynamic force with static force.Secondly,the calculation model is established according to the limit analysis of theory and Mohr-Coulomb strength criterion.Finally,through the principle of virtual power,we got the horizontal foundation of shallow tunnel and tunnel surrounding rock pressure calculation formula of limit bias.This paper uses the safety coefficient method to analysis the safety and stability of the existing tunnel.First of all,the author according to the load on both the characteristics of tunnel structure,we got the blasting vibration on the existing tunnel damage equivalent shear and tensile equivalent formula.Secondly,the author uses the finite difference software calculating model was established,which is based on Mohr-Coulomb and strength reduction principle.Finally,through the common judgment criterion of instability,we got the safety factor of tunnel under different vibration velocities and change regulation.Field test research was carried out based on the two typical conditions.First of all,we carried out parallel tunnel blasting vibration and blasting technology test effect on the existing tunnel control,and using common nonel detonator and digital electronic detonator in test,the results show:The common Nonel Detonator vibration propagation law v=140.41(Q^1/3/R)^1.41,and the maximum vibration velocity in the cutting section.Compared with,the digital electronic detonator has good damping effect,the delay time is 25ms.Secondly,we have done experiments on open pit blasting,the test results show:The optimal delay time of digital electronic detonator is 17ms;The blasting vibration damping hole on the same level of communication with good damping effect;The free surface normals than normal vertical tunnel initiation free surface vibration velocity of parallel tunnel is high.Final,we use the safety coefficient method to evaluate the safety and stability of the existing tunnel,the evaluation results show:Using digital electronic detonator,compared with the parallel tunnel blasting,the safety and stability of existing tunnel is increased 52.6%;Open air blasting engineering,with single vibration damping hole,double vibration damping hole,the bottom of the hole and the free surface and change the direction,the safety of existing tunnel stability are increased by 11.25%,12.75%,10.75%and 16.25%.