Vibration vulnerability of shotcrete on tunnel walls during construction blasting

Ahmed, Lamis; Ansell, Anders

doi:10.1016/j.tust.2014.02.008

Cited by 36 publications

(22 citation statements)

References 10 publications

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“…At present, in the study of the influence of temperature and humidity on the adhesion strength of shotcrete-to-rock, Tang [14] et al used a novel indoor temperature and humidity control system to evaluate the effect of temperature and humidity on the adhesion strength of shotcrete-rock coupling. As Figure 3 shows, it can be noted that based on the data obtained under different working conditions, as the temperature increases from 50°C to 90°C, the adhesion strength of shotcrete-to-rock decreases under all working conditions, and it can be noted that temperature had a significant effect on the adhesion strength, but it was not the only influencing factor [34][35][36]. As can be seen from the data in Figure 4, when the humidity increases from 25 to 90% under the same conditions, the adhesion strength of the shotcrete-to-rock interface will be significantly improved, and it can be found that, under the same humidity conditions, when the temperature rises to a certain limit, the longer the curing age, the lower the adhesion strength.…”

Section: Effect Of Temperature and Humidity On Adhesion Strength Of Smentioning

confidence: 99%

Influence of Ground Temperature on Shotcrete-to-Rock Adhesion in Tunnels

Duan

Zhang

Lai

2019

Advances in Materials Science and Engineering

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Long and deep tunnels are increasingly designed and built worldwide, often in severe geothermal environments characterized by high temperature in the rocks. is issue cannot be ignored because high temperature definitely affects the strength of the adhesion between the concrete and the surrounding rocks, whatever the lining cast in place, segmental or sprayed using shotcrete. e causes of geothermal heat and the effect of the temperature on tunnel linings during and after their construction are recalled and discussed in this paper. Both temperature and humidity are shown to be the most relevant factors affecting adhesion strength, whose loss is related to the microdamage in the shotcrete layers closest to the rock. Possible ways to improve adhesion strength and to minimize the high-temperature detrimental effect are also presented and discussed.

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Section: Effect Of Temperature and Humidity On Adhesion Strength Of Smentioning

confidence: 99%

Influence of Ground Temperature on Shotcrete-to-Rock Adhesion in Tunnels

Duan

Zhang

Lai

2019

Advances in Materials Science and Engineering

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“…Shock and Vibration 5 results [4][5][6][7]. Analysis of monitoring data (Table 3 and Figure 9) showed that PPV-Z values at blasting vibration monitoring points were about 1.5-2 times higher than PPV-X and PPV-Y.…”

Section: Empirical Equation Of Ppvmentioning

confidence: 99%

“…Practically, the next blasting cycle should be performed after the final setting strength of shotcrete is reached and a certain distance should be kept between blasting and shotcrete positions. However, if shotcrete is exposed to vibrations at early ages, while it is still in hardening stage, cracks and sheddings may occur in the structure adversely affecting the function of hard concrete, even causing the failure of the whole support structure [7]. To ensure the security of shotcrete, the effect of blastinduced vibrations should be investigated and safety distance threshold from blasting work face, where shotcrete can withstand blast vibration, should be determined [8,9], as shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…Numerical simulations have also been applied in the prediction of vibration damage to shotcrete due to tunnel explosions based on elastic stress wave theory and structural dynamics [7,10,19,20]. Safety distance thresholds for shotcrete can be evaluated based on different criteria such as maximum tensile stress and Mohr-Coulomb criteria.…”

Section: Introductionmentioning

confidence: 99%

“…is paper aims to determine the safety distance of shotcrete based on the bond failure of shotcrete-rock interface subjected to blasting in tunnel excavations. In this paper, an analysis method based on both in situ tests and theoretical solutions has been used, an approach similar to that in [5][6][7]22] but here applied for different geological conditions and tunnel geometries. e monitoring scheme with symmetry testing points inside the rock has been carried out for blast vibration monitoring in the large-span tunnel.…”

Section: Introductionmentioning

confidence: 99%

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Safety Distance of Shotcrete Subjected to Blasting Vibration in Large‐Span High‐Speed Railway Tunnels

Zhang

Fang

et al. 2019

Shock and Vibration

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e drill and blast method is widely used in constructing tunnels in rock. Unfortunately, blasting vibration can damage newly performed shotcrete layers which are major support structures to stabilize surrounding structures. erefore, investigation of the influence of blasting on shotcrete and determining reasonable distance between blasting work face and shotcrete position is of great importance. In this paper, a large-span tunnel excavated by drill and blast method acting as a high-speed railway station has been investigated. Blast vibration in the tunnel was recorded using microseismic monitoring technique. Empirical prediction equations for peak particle velocity (PPV) were obtained through regression analysis based on the obtained monitoring data. e attenuation law of tensile stress imposed on shotcrete layer due to blasting and bond strength of shotcrete-rock interface was also investigated. Minimum safety distance between shotcrete and blasting positions was calculated based on bond failure criterion. Evolution law considering different factors including blasting charge, rock mass class, and setting time of shotcrete was also obtained, which could be applied to determine blast charge shotcrete arrangements for tunnel constructions in future. e obtained results showed that the safety of shotcrete could be ensured and shotcrete falling off the rock could be prevented under current blast constructions.

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Simulating the response of buried structures to external blast loads: Methods, challenges, and advances

Mohammadi

Khalilpour

Sareh

2022

Engineering Reports

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Various methods have been proposed to ensure the serviceability of buried structures such as road tunnels, urban utility tunnels, water conduits, underground shelters, and deposition chambers against extreme loads, the most common of which are experimental and computational methods. An external explosion in the vicinity of such structures is one of these extreme loads. In general, different types of external blasting for buried structures can be classified as surface blasting, coupled or uncoupled buried explosions, excavation by drilling and blasting near the structure, and the accidental detonation of explosive depositions. Laboratory or field tests for explosions are usually limited by financial and safety constraints; therefore, numerical simulations are often regarded as a vital tool in the study of such problems. Though computer software and hardware have improved rapidly in recent decades, and various numerical solvers have been developed, there is no universal method for solving all external explosion problems. Each numerical method can produce sensible results under certain conditions and assumptions, along with its limitations in computational cost. Consequently, these problems have been particularly difficult to investigate, and even in some cases, the results of different studies seem to be inconsistent. Besides providing an extensive review of the available literature in the field of numerical simulation of external explosions near buried structures and a discussion of the damage criteria associated with such explosions, this study also highlights some inconsistencies that may need further investigation.

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Vibration vulnerability of shotcrete on tunnel walls during construction blasting

Cited by 36 publications

References 10 publications

Influence of Ground Temperature on Shotcrete-to-Rock Adhesion in Tunnels

Influence of Ground Temperature on Shotcrete-to-Rock Adhesion in Tunnels

Safety Distance of Shotcrete Subjected to Blasting Vibration in Large‐Span High‐Speed Railway Tunnels

Simulating the response of buried structures to external blast loads: Methods, challenges, and advances

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