Study of the wavefield generated by a gas exploder used for artificial avalanche release

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• 作者：E. Suriñ ; ach^a ; ^{emma.surinach@ub.edu} ; I. Vilajosana^a ; ^b ; ^{ivilajosana@worldsensing.com} ; K. Kleemayr^c ; ^{karl.kleemayr@uibk.ac.at} ; L. Rammer^c
• 关键词：Snow avalanche ; Artificially release ; Detonation wavefield ; Seismic record ; Gazex® ; device
• 刊名：Cold Regions Science and Technology
• 出版年：2011
• 出版时间：April 2011
• 年：2011
• 卷：66
• 期：1
• 页码：17-29
• 全文大小：2852 K

文摘

A study of the entire wavefield (3D) generated by the detonation of a Gazex® device performed on the Gamsleiten slope, at Obertauern, Austria is presented. The main aim of the study was to determine whether the detonation can trigger snow avalanches in remote locations. A linear array of sensors in the vicinity of the blasting point combining six 1D and two 3D seismic sensors was deployed. Three independent Gazex® detonations were subsequently triggered in intervals of approx. 15 min. The signals obtained were similar. Waves propagating through the ground (P waves) and sound waves were clearly detected. The corresponding ground velocities and accelerations were determined. The frequency content of the whole signals was band-limited to 10–40 Hz, although the frequency content of P waves was lower than that of sound waves in the three components. A different behaviour in the frequency content evolution of the two wave groups was observed. P waves suffered distortion and attenuation with distance. This was not observed in the sound waves which showed local amplifications. The maximum values of the velocity and acceleration measured correspond to the sound waves observed in the horizontal components. The values of the ground accelerations obtained for the whole signals were 6 times lower than the value of the critical acceleration, which is the value that is required for the inclined snow slab to be stable. Cumulative snow slab displacements caused by long vibrations were also considered. The results suggest that in this case the likelihood of a snow avalanche release due the Gazex® device detonations is low. However, this result cannot be generalized to other snow and terrain conditions and to other conventional explosives. Specific studies should be carried out at the target sites/situations. Another important finding was the significant contribution of the horizontal components to the ground movement. This indicates that it is necessary to consider the whole wave field (3D) in this type of study.