Influence of the Spacing of Tunnel Groups on Rock Burst in Hard Rock with Extremely High In-situ Stress
In extremely hard rock tunnels with high in-situ stress,reasonable tunnel clear distance not only affects the utilization rate and economy of the tunnel space,but also has a great impact on the severity of rock burst in the tunnel.Reasonable tunnel clear distance can meet the requirements of structural safety and tunnel economy to the maximum extent,so it is very important to find the appropriate tunnel clear distance.Based on the proposed high in-situ stress tunnel of Longmen Mountain between Chengdu and Wenchuan,five kinds of tunnel clearances are designed.In order to find a reasonable tunnel clearances,the displacement and stress of tunnel wall under the five kinds of clearances are analyzed respectively.The influence of the change of the clear distance on the displacement and the maximum principal stress under different lateral pressure coefficients is analyzed,and the rock burst tendency of every working condition is analyzed using the rock burst criterion of elastic strain energy.The results show that:With the increase of the clear distance of the tunnel,the influence between tunnel groups decreases,and the stress and displacement of the feature points on the side near the intermediate sandwiching rock have obvious changes;The maximum principal stress of the tunnel wall near the middle rock sandwiching side is greater than that far away from the middle rock sandwiching side,and rock burst is more likely to occur;When the lateral pressure coefficient is 0.8 and 1,the reasonable clear distance is 1.5D(D is width of the main hole),and when the lateral pressure coefficient is 1.2 and 1.4,the reasonable clear distance is D.
tunnelsclear distancein-situ stressrock burstelastic strain energy
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万方数据
维普
