| In a lot of tunnel's close construction, besides the static influence for the stress re-distribution by the reason of excavating tunnels, it must consider the vibration effect with which using the boring and blasting method in rock. This paper combined the weak-vibration controlled blasting technique, with the example of Yanjin No.l tunnel of Neijiang-Kunming railway down-through some buildings of Yanjin county, especially the seven-floors nation-revenue building, carrying out fruitful research towards tunnel's close construction blasting controlling technique.As well known, the basic characteristic of tunnel engineering are the complexity of geological environment and difficulty to acquire geology and surrounding rock's blasting design parameter exactly. For quite a long time, the blasting design of tunnel engineering is mainly calculated by experience formula and engineering analogy. So the technique path of this paper is field test, through site monitor measuration, continuously feedback and adjust blasting parameter, thereby reach the goal of disturb-decouple.Based on lots of investigation and research, this paper study and expatiate the origin, actuality and development of weak-vibration blasting technique, therefore, bring forward the research method:combining the rock blasting excavation test of practice engineering, testing blasting vibration attenuation law. Analysing the spectroscopy of blasting vibration waveform, dividing frequency groupingly, adjusting blasting design parameter continuously, make sure the appropriate blasting parameter ultimately, insuring the constructing plan of new-construction tunnels and the safety of existent structure.This paper is carrying out systemic expatiate of weak vibration blasting controlling technique, combining field experiment, expatiate test process and test parameter, feedback analysis based on blasting vibration spectrum, by the way of the bases of next phase's parameter adjusting, and reaching the disturbing damoing goal ultimately. Being the important parts of control blasting technique, this paper study on grain side blasting principle and smooth blastmg testing as well.At last, through the research and construction with the disturbing vibration control blasting technique of Yanjin-1 tunnel, achieving the ideal research fruits,controlling the speed of weak vibration blasting under 2.0cm/s. The truth has proved: using disturbing blasting method and combining synthesis damping methods, using high degree of accuracy detonator blasting, it's a good construction method to control blasting quake intensity and insuring the safety of earthface buildings. Meantime, enducing the optimal disturbing postponed time At is 1/2 of rock vibration cycle T, t=T/2; In order to avoid the nestification of blasting shake, the time of postponed outburst must be 3 times greater than rock vibration cycle. The time of postponed outburst is 2.5 times rock vibration cycle. These results are hopeful to have more benefit and development in allied engineering aftertime. |
