Seismic Response Of Released Rock Zone Of Deep Tunnel

With the rapid development of China’s basic traffic engineering construction, the number of railway, highway tunnels rapidly rising; and our country is a much earthquake country, as a result of the earthquake damage of the tunnel caused by too many to count. In the study of seismic design and performance for all types of damage, the range of tunnel surrounding released rock zone and its determination,the effects of released rock zone on support structure, these are very important, these factors determine the use of the methods, principles of seismic design, the use of materials, the selection of structure type and many other aspects.In this paper, the use of software FLAC3 D were studied in the earthquake prone areas with none of released rock zone and formation of released rock.Firstly, study on the development of the tunnel surrounding released rock zone and broken zone under seismic loads, put forward the expansion of released rock zone further.Secondly, in each direction observing the acceleration-time curve of original monitoring points in surrounding rock under seismic load, comparing before and after the tunnel excavation the acceleration-time curve of each monitoring point under different seismic intensity, thereby determining the affects of different intensity of the seismic input for the development of released rock zone in the size of the case, and analyzing the range of released rock zone and the range of plastic zone.Finally, according to the different thickness of surrounding released rock zone and binding force, explore the cushion effect of released rock zone on lining structure;taking into account the additional stress of the released rock zone on supporting structure as dead load, and compare the stress value of the supporting structure when the released rock zone was used as cushion and weight load.