Dissertation > Transportation > Road transport > Tunnel project > Tunnel construction > Tunneling,guided Lane and support

Research on Pressure-relief Support Technique for High Initial Stressed Tunnel at Depth

Author GuoXiangCan
Tutor DaiJun
School Xi'an University of Science and Technology
Course Geotechnical Engineering
Keywords Highland stress Zonal disintegration Destress Blasting Numerical Analysis Tunnel Support
CLC U455.7
Type Master's thesis
Year 2010
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With the development of transport and energy extraction into the tunnel under the deep, Highland stress conditions effectively support nursing became underground engineering must face one of the problems. The Heights under stress conditions, using ordinary strengthen support law enforcement, is not only a waste of a lot of manpower, material and financial resources, and poor support. Often the supporting structure is severely damaged, the repair rate is high. Therefore, to explore methods of the tunnel effectively supporting Highlands stress conditions, to ensure the long-term security and stability of the tunnel, and to improve the effect of tunnel support, reduce the tunnel support structure failure rates and the cost of supporting it is urgent to have important theoretical and practical significance. Based on the the zonal disintegration theory and blasting damage theory, the paper uses theoretical calculation analysis and numerical simulation methods, relief of the buried deep Highlands stress tunnel support technology research. The specific research main research results obtained are as follows: (1) based on the principle of zonal disintegration, according to the location of the partition rupture zone width determined charge position and blasting unloading area, the use of the corresponding partition rupture with the radius and width formula Destress Blasting parameters to be determined. By calculating the gun hole depth of 9.0m; charge weight to 0.55kg, 0.45kg, 0.40kg, 0.35kg; stemming length to 8.12m, 8.27m, 8.35m, 8.43m. (2) According to the blast damage theoretical calculation of the value of surrounding rock stress relief hole spacing and relief after gun hole spacing of 0.7m, 0.8m, 0.9m, 1.0m. Combined with the knowledge of mechanics of materials and tunnel support theory to calculate the thickness of the tunnel lining structure and internal forces. Lining thickness is reduced by 1.5m before relief to the relief of 0.9m, 0.75m, 0.6m, 0.8m, and relief after the lining structure moment and axial force is also reduced by 37% or more, indicating that the blasting relief to obtain the desired effect. (3) the use of ANSYS / LS-DYNA dynamic finite element software simulation numerical model, loose blasting relief support to simulate and study the blasting relief parameters and pressure relief effect relationship. Analysis of simulation results obtained: Destress Blasting the lining structure deformation and internal forces are reduced in varying degrees, the deformation is reduced more than 47%, and the internal force is reduced by 35% or more, and is consistent with the results of theoretical studies, indicating that Destress Blasting achieve the purpose of improving the conditions of the surrounding rock support. Relief Tunnel Surrounding Highlands stress transfer to the deep surrounding rock away from the tunnel surface, which can reduce the stress of surrounding rock blasting through the loose, the protection of the purpose of the tunnel. The results of this study of the buried deep Highlands stress underground engineering construction and energy development have certain guiding significance and reference value.

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