Experimental Study On Abnormal Contact Of Underground Concrete Buildings By Seismic Wave Transmission Tomography

Underground concrete structures generally adopts the slurry-supported. By using the method of piecewise pouring to become one whole. This method can be applied to all kinds of size, shape of the concrete structure is completed. In concrete pouring process, due to uneven material particle size, tamping, complex geological conditions, construction conditions and construction, construction technology and process is not mature, the appearance of concrete structure and internal possible defects such as mud, hollow, thus brings to the engineering safety hidden trouble. Seismic CT transmission tomography technology of concrete of the meticulously probing ability is stronger, in terms of concrete structures fine probe has important application value.This paper through the forward modeling for seismic wave in underground concrete structures at different anomaly of the contact zone with the response characteristics were studied. The wave velocity distribution of CT images is obtained by numerical simulation. On this basis, concrete physical model study on contact anomalies of underground concrete structures is builded. The use of physical model test research, through the meshing, first break picking, then inversion imaging, to obtain concrete section internal shock velocity profile, according to the wave velocity size differences inside the concrete geological characteristics were analyzed and explained. It is concluded that the concrete structure of contact area image reconstruction favorable collection, observation system and reconstruction method, locate the contact abnormal body size, shape and space location, at the same time of seismic CT transmission tomography technology have a certain understanding.The paper also points out the shock wave CT transmission tomography technique in the concrete application, existing problems and the future research direction of the use of wave velocity to the adoption plastid internal structure characteristics, not to conduct the thorough research to the boundary effect, did not give a direct transmission line tracing method of quantitative evaluation basis, In the study of the future seismic CT transmission tomography observation system should be optimized to take full advantage of seismic waves contain other physical parameters, to improve the accuracy of the ray tracing, inversion algorithm. Figure [27] table [4] references [68]...