Study On Prediction Of Rock Burst In Qamchiq Railway Tunnel

The length of Qamchiq railway tunnel in Uzbekistan is 19.268 km,and the elevation of entrance is 1480 m while the elevation of exit is 1275 m.The maximum depth of the tunnel is about 1275 m,it belongs to ultra-deep tunnels,which has extremely high ground stress.The main lithology of the tunnel area is granite,granodiorite,granite porphyry and syenite porphyry.The integrity of the lithology is good,and the lithology intensity is strong,which can easily lead to strong rock burst.Qamchiq electrified railway tunnel is a pivotal and significal part of entire Angren-Pap railway project,if the prediction and fortification of the rockburst hazards are not carried out,it will cause a huge delay,economic loss and even casualties.So it is necessary to do the prediction research in tunnel.In order to control the hidden danger caused by rock burst in Qamchiq tunnel,this paper will research and predict the intensity of rockburst through data research,theoretical analysis,numerical simulation and fuzzy evaluation.The specific research contents and conclusions are as follows:(1)Based on the research about the mechanism of rockburst,by referring to the result of the tunnel rockburst prediction,prevention technology and combining with the specific characteristics of rockburst in the construction process,the intensity level of rockburst will be divided.(2)The numeriaclly simulate of the main tunnel and satety tunnel will be done by FLAC3 D.The final intensity level will be caculated by the using of Russense criterion and Turchaninov criterion by the reference of the secondary stress obtained.(3)Selecting the appropriate evaluation factors and applying the fuzzy analytic hierarchy process(FAHP)to predict the rock burst in the main tunnel and the safe tunnel in Qamchiq tunnel.Compared with the rock burst grade in actual construction,the advantages and disadvantages of various methods are summarized.Finally,according to the principle of maximum intensity level,the level of rock bolting protection in the Qamchiq tunnel will be determined.