Safety distance for secondary shotcrete subjected to blasting vibration in Jinping-II deep-buried tunnels

Yang, Jianhua; Lu, Wenbo; Zhao, Zhenguo; Peng, Yan; Chen, M.

doi:10.1016/j.tust.2014.04.008

Cited by 37 publications

(34 citation statements)

References 25 publications

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“…where σ d is the dynamic stress of the rock material, ρ · c represents the wave impedance of the rock material, and V denotes the vibration velocity of the rock material. e in situ vibration velocities of the abovementioned measurement points [7] and the vibration velocities of the measurement points in the indoor model test [8,9] were incorporated into equation (10) to solve for the tensile stress in the theoretical axial direction of the concrete. Subsequently, the e ective tensile stress values in the axial direction for the abovementioned measurement points were extracted from the nite element model in this study.…”

Section: Resultsmentioning

confidence: 99%

“…To date, a number of studies on the roles and principles of blasting construction and the related effects on tunnel lining structures have been released. Using the finite element method, Yang et al [10] found that the secondary shotcrete should be constructed at least 24 m away from the blasting face to avoid vibration-induced failure. Jiang and Zhou [11], Jiang et al [12], and Ahmed and Ansell [13,14] studied the maximum peak vibration velocity allowed by a structure in a secure state.…”

Section: Introductionmentioning

confidence: 99%

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Vibration Failure of Young Low‐Temperature Concrete Shaft Linings Caused by Blasting Excavation

Xie

Zeng

et al. 2019

Advances in Civil Engineering

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The freezing-blasting method constitutes the only available technique for excavating mining shafts within water-bearing bedrock. This study explores the effects of vibration damage to young C65 concrete shaft linings caused by close-range blasting excavation using the finite element method. C65 concrete test specimens were made in the laboratory and then cured at −7°C, and the elastic modulus, compressive strength, and longitudinal wave velocity were tested. The allowable dynamic tensile strength of the concrete for each mold of the shaft lining was obtained according to the observed strain rate of the concrete shaft lining using a regression formula. The finite element simulation results are basically consistent with the in situ measurements, thereby attesting to the validity of the numerical simulation. The blasting-induced vertical peak vibration velocity of the first mold of the concrete shaft lining reached 20∼25 cm/s, which far surpasses the allowable vibration velocity range (i.e., 2∼3 cm/s) in the Safety Regulations for Blasting for newly cast concrete between the initial setting and an age of 3 d. The tensile stress of the first concrete mold calculated by the finite element method is approximately equal to the theoretical tensile stress, both of which are smaller than the dynamic tensile strength of concrete. The cumulative energy sustained by the shaft lining of each mold and the allowable values of the dynamic tensile strength were obtained. The growth rate of the dynamic tensile strength of the subsequent molds was larger than that of the cumulative energy, and thus the safety of the shaft lining gradually improved. The C65 concrete would therefore not experience tensile failure after the shaft lining has sustained multiple rounds of blasting loads. This finding can provide a basis for safety considerations when employing the freezing-blasting method to construct mining shafts in water-bearing bedrock.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Vibration Failure of Young Low‐Temperature Concrete Shaft Linings Caused by Blasting Excavation

Xie

Zeng

et al. 2019

Advances in Civil Engineering

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show abstract

“…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%

“…ese advantages allow shotcrete to be widely used as a construction technique in tunnels excavated by the drill and blast method [1][2][3]. Usually shotcrete and blasting operations are performed alternately, and the main function of shotcrete is to provide a safe working environment for workers and facilitate subsequent operations of support construction such as installing metal meshes and bolts [4,5]. erefore, high capability of projecting shotcrete on rock surfaces is vital to the safety of workers and the function of tunnels [6].…”

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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Safety distance for secondary shotcrete subjected to blasting vibration in Jinping-II deep-buried tunnels

Cited by 37 publications

References 25 publications

Vibration Failure of Young Low‐Temperature Concrete Shaft Linings Caused by Blasting Excavation

Vibration Failure of Young Low‐Temperature Concrete Shaft Linings Caused by Blasting Excavation

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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