Vibration and Cracking of Tunnel Lining Due to Adjacent Blasting

Nakano, Ken-ichiro; Okada, Shigeru; Furukawa, Katsuko; Nakagawa, Koji

doi:10.2208/jscej.1993.462_53

Cited by 10 publications

(9 citation statements)

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“…Kendorski et al [29] reported that the cracks in the shotcrete lining of underground tunnels occurred when the PPV exceeds approximately 1.22 m/s. Nevertheless, Nakano et al [30] stated that the shotcrete cracking produced by an adjacent tunnel explosion occurred when the PPV reached 0.7 m/s. Table 1.…”

Section: Blast Damage Assessment Methods Of a Box-shaped Tunnelmentioning

confidence: 99%

Blast Damage Assessment of Symmetrical Box-Shaped Underground Tunnel According to Peak Particle Velocity (PPV) and Single Degree of Freedom (SDOF) Criteria

et al. 2018

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This study aimed to determine the reliability of the damage criteria that was adopted by the peak particle velocity (PPV) method and the single degree of freedom (SDOF) approach to assess the damage level of a box-shaped underground tunnel. An advanced arbitrary Lagrangian Eulerian (ALE) technique available in LS-DYNA software was used to simulate a symmetrical underground tunnel that was subjected to a surface detonation. The validation results of peak pressure into the soil revealed a good consistency with the TM5-855-1 manual within differences that were much less than previous numerical studies. The pressure contours revealed that the blast waves travelled into the soil in a hemispherical shape and the peak reflected the pressure of the tunnel that occurred immediately before the incident pressure reached its highest value. The assessment results proved that the criteria of the above methods could efficiently predict the damage level of a box-shaped tunnel under different circumstances of explosive charge weight and lining thickness at a depth of 4 m within slight differences that were observed during van and small delivery truck (SDT) explosions. However, the efficiency of both the methods was varied with the increase of burial depth. Whereas, using the PPV method significantly underestimated or overestimated the damage level of the tunnel, especially during SDT and container explosions with a lining thickness of 250 mm at burial depths of 6 and 8 m, respectively, the damage level that was obtained by the SDOF method greatly matched with the observed failure modes of the tunnel. Furthermore, new boundary conditions and equations were proposed for the damage criteria of the PVV method.

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Section: Blast Damage Assessment Methods Of a Box-shaped Tunnelmentioning

confidence: 99%

Blast Damage Assessment of Symmetrical Box-Shaped Underground Tunnel According to Peak Particle Velocity (PPV) and Single Degree of Freedom (SDOF) Criteria

et al. 2018

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“…From measurements during construction of parallel tunnels Nakano et al 2 concluded that cracking of shotcrete occurred when the vibration particle velocities exceeded 700 mm/s, with a maximum of 1450 mm/s. The Canadian tests by Wood and Tannant 3 and McCreath et al 4 showed that steel fibre-reinforced shotcrete maintains its functionality even though exposed to vibration levels of 1500-2000 mm/s.…”

Section: Vibration Resistancementioning

confidence: 99%

“…The shotcrete and rock material properties are given in the previous sections and the value of the dynamic elastic modulus of the shotcrete is thus 26 GPa, in accordance with equations (1) and (2). The thickness h of the shotcrete was assumed to be 40 mm with a length given by the placement of the measurement points, typically 10-20 m. The effect of 500 mm fractured rock was accounted for through the choice of material parameters.…”

Section: Numerical Calculationsmentioning

confidence: 99%

“…No vibrations were measured during these tests. Nakano et al 2 present tests performed during the construction of parallel tunnels where the smallest distance between blasting and shotcrete was 1 . 0 m. Results from tests in a Canadian goldmine with steel fibre-reinforced and steel mesh-reinforced shotcrete areas subjected to vibrations from small-scale detonations are presented by Wood and Tannant 3 and McCreath et al 4 It was found that steel fibre-reinforced shotcrete maintains its functionality even though exposed to high vibration levels where unreinforced shotcrete fails.…”

Section: Introductionmentioning

confidence: 99%

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Shotcrete on rock exposed to large-scale blasting

Ansell

2007

Magazine of Concrete Research

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Shotcrete sprayed on rock is vulnerable to stress waves from large-scale blasting in tunnels and mines. Shotcrete support in a Swedish underground mine is studied through numerical analysis and comparisons with previous results, measurements and observations in situ. A previously developed finite-element model that consists of beam and spring elements is used to calculate the response of shotcrete to vibrations from production blasts in the mine. The modelling approach is similar to that of a building during an earthquake, with accelerations measured in situ used as loads. The analysis shows that the calculated bond stresses exceed the strength in the interface between shotcrete and rock close to the blasts. The results show that it is possible to optimise the scheme of the blasting so that shotcrete is protected from damaging vibrations. Also recommended, for practical use, are minimum distances to large amounts of explosives given. This set of recommendations is a supplement to previously given guidelines valid for small amounts of explosives at short distances from shotcrete on rock.

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“…2 m. No vibration levels were recorded during these tests. Nakano et al 2 present tests performed during the construction of parallel tunnels where cracking of the shotcrete was observed when the vibration particle velocities exceeded 700 mm/s. Particle velocities of 1450 mm/s were reached during the tests and the smallest distance between blasting points and shotcrete is reported to have been 1 .…”

mentioning

confidence: 99%

Recommendations for shotcrete on rock subjected to blasting vibrations, based on finite element dynamic analysis

Ansell¹

2005

Magazine of Concrete Research

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Shotcrete is sprayed concrete applied pneumatically on, for example, a rock surface to prevent fallout of rock blocks and thereby securing the arch-shape of a tunnel profile. A finite element model, especially adapted to the dynamic analysis of shotcrete on rock that is subjected to vibrations from blasting, has been developed and tested. The model consists of spring and beam elements that are used to simulate the behaviour of an elastic concrete area, bound to a rock surface through adhesion. This facilitates the calculation of a two-dimensional displacement field, using mode superposition and Duhamel's integral. The loads applied on the model are accelerations that give rise to inertia forces on the system. The accelerations are calculated from given weights of explosives, geometrical conditions and rock properties. The presented numerical examples demonstrate the response of shotcrete to vibrations, based on material data from an extensive literature survey. A series of calculations are compiled to give recommendations for how close to shotcrete blasting in rock can be allowed.

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Vibration and Cracking of Tunnel Lining Due to Adjacent Blasting

Cited by 10 publications

References 0 publications

Blast Damage Assessment of Symmetrical Box-Shaped Underground Tunnel According to Peak Particle Velocity (PPV) and Single Degree of Freedom (SDOF) Criteria

Blast Damage Assessment of Symmetrical Box-Shaped Underground Tunnel According to Peak Particle Velocity (PPV) and Single Degree of Freedom (SDOF) Criteria

Shotcrete on rock exposed to large-scale blasting

Recommendations for shotcrete on rock subjected to blasting vibrations, based on finite element dynamic analysis

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