Monitoring Study On Blasting Vibration By Excavation Of Large Cross-Section Shallow Urban Tunnel Constructed In Hard Rock Mass

The paper studies the influence of blasting seismic wave caused by the construction of the shallow, big span ,big rock tunnel with the drill-blasting method in Qingdao , beginning with studying the transmission field of blasting seismic velocity,taking blasting vibration monitoring on site as the basic research methods,basing on the Qingdao end connection project of the jiaozhou bay undersea tunnel in Qingdao ;and researches the vibration velocity size of the surface in different depth and position and the surface vibration characteristics and the changing laws in the excavation blasting process of the tunnel;which aims to predict the blasting vibration effect in order to ensure the safety of the building and put forward reasonable suggestions in the construction of the shallow and big rock tunnel with the drill-blasting method in city. Test results show that:1,this paper described the theories of rock blasting damage mechanism,evaluated their applicability;clarified the mechanism,types and characteristics of blasting seismic wave.2,Under the conditions of the free surface, the difference of vibration effect is bigger caused by blasting in the different types of blast hole,in which the blasting vibration effect of cutting blast hole is most strongly.3,The forms of the blasting velocity field are different.in different depth and regional.Due to the regional characteristics of the surface vibration caused by driving and blasting the hard rock tunnel in Qingdao, thus the damping law of surface vibration cannot use single vibration damping parameters to describe. According to the test results,the tunnel is divided into 3 types of surface area: set foword influence area of blasting,left and right lateral area of blasting,cavity pocket influence area of blasting.The damping parameters of seismic wave in every area of hard rock tunnel are gained, through the study of the regularities of distribution of vibration velocity of the blasting influence area in different depth and the formula regression.4,The paper give qualitative and quantitative research about the shock wave of the composite blasting caused by the wedge cut blasting. 5,The building influenced most by the adjacent tunnel is monitored , Through monitoring and feedback,the tunnel picks through the adjacent influence section safely and smoothly,Proof of the blasting vibration monitoring is a effective means of the problems caused by blasting effect building, it is the key for construction the Nearly meet engineering Successfully.