Study On Control Standard Of Blasting Vibration Safety Of Excavation For The Cold Area Of Large Hydropower Station Reconstruction Engineering

The construction of water conservancy project completed in the last century in China, after long time operation, although the middle to take various kinds of measures to carry on the reinforcement, but many projects are also different extent into the aging period, face reconstruction problem. In this paper, with the Fengman Hydropower Station reconstruction project dam foundation blasting excavation as the background, the theoretical calculation, numerical simulation and field test method and under conditions of cold on the ground is frozen, the blasting vibration attenuation law and changes in building blasting vibration safety control standard, the main conclusions are as follows:(1) under the cold condition, rock were frozen and the peak velocity of blasting vibration and blasting vibration frequency were increased; in rock fissure water of blasting stress wave high frequency components with filtering function and water formed after the ice, the filter significantly weakened.(2) cold under the condition of a certain depth beneath the surface is frozen, effect of blasting vibration attenuation parameters and alpha decreased and with increase of the depth of frozen, blasting vibration attenuation parameters and alpha were further reduced, the rock mass to the completeness of the state transition; rock mass of water rate is higher, the frozen before and after blasting vibration attenuation parameter’s fluctuation more.(3) surface rock mass were frozen, building tensile stress, pressure should be force and blasting vibration velocity were increased significantly, and with increase of the depth of frozen ground, building dynamic response more; according to the corresponding force and vibration velocity of the ice layer thickness and the building of the maximum tensile stress relationship are different frozen depth of the building vibration safety control standard.(4) Compare the blasting vibration characteristic of excavation during summer and winter; fitting attenuation of summer and winter to get the value of K and α two seasons, and compared with numerical simulation results to verify the reasonableness of model calculations;the blasting vibration monitoring data of different shields in winter were in control of the allowable range, will not cause harm to the surrounding plant units.