Influence Laws Of Ground Particles Caused By Large Span Tunnel Blasting Construction In Hard Rock

Monitoring schemes are designed according to both the blasting schemes in testing aeras and the testing lines of the measuring points. The testing lines are parallel or vertical to the tunnel axis and they are fixed on the front, on the back and on the lateral of the working face, combining conditions of the Qingdao side connection project which belongs to the Kiaochow Bay undersea tunnel. Based on the monitoring data data, the vibration laws of the ground particles are studied systematically certain limits areas. The vibration laws of ground particles changed along the distance are got by the mathematical statistics method. Specific research contents include:(1) the vibration laws of ground particles parallel to the tunnel axis, (2) the vibration laws of ground particles vertical to the tunnel axis, (3) computing formula of the blasting vibration velocity of ground particles. The vertical vibration velocity and the horizontal vibration velocity of blasting with their main vibration frequency are got.Vibration laws of ground particles are follows:(1) the changeing characteristics of the vertical vibration velocity and horizontal vibration velocity of ground particles on the tunnel axis are concussion. (2) In the range of 10m to 20m in horizontal distance to the center of blasting, "maximum vibration effect" existes, and the changing laws of the vertical vibration velocity and horizontal vibration velocity of ground particles doesn't accord with Sodev's formula. (3) The maximum value of the vertical vibration velocity of ground particles from the explosion appeares in the distance of 5m to 20m. And this value is 1.04 to 3.1 times of the vertical vibration velocity above the center of blasting. (4) The maximum value of the horizontal vibration velocity of ground particles from the explosion appeares in the distance of 5m to 15m. And this value is 1.1 to 6 times of the horizontal vibration velocity above the center of blasting. (5) The frequency of the vertical vibration and horizontal vibration in range of 10Hz to 120Hz. The change laws of vibration frequency are not clear.The value of K andαin Sodev's formula of Qingdao granite is calculated by linear regression. Based on the measured data, regional prediction formula of vertical vibration velocity of ground particles above the tunnel axis is got by curve fitting. Measuring schemes and laws got in this paper instruct security construction effectively, and also provide important reference for similar engineering. Empirical formula established in this paper reflects the phenomenon of"maximum vibration effect", and this kind of formula provides important ideas for the related blasting theory in the future studies.