Novel rockburst criterion based on the TBM tunnel construction of the Neelum–Jhelum (NJ) hydroelectric project in Pakistan

Ma, Chishuai; Chen, W.Z.; Tan, Xuyan; Tian, Hongming; Yang, Jianping; Yu, Jianxin

doi:10.1016/j.tust.2018.06.032

Cited by 32 publications

(15 citation statements)

References 19 publications

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“…The interbedded formation commonly dips steeply with the tunnel axis perpendicular to the strike lines; moreover, the contact among beds is gradational. The fault structures affected this bidding structure, which resulted in a horizontal structure; thus, the steeply dipping structure was converted into a drag fold [23][24][25].…”

Section: Project Geology Detailsmentioning

confidence: 99%

“…The prediction criteria, which are based on the strength-to-stress ratio, measure the strength of the rock, which is attained from laboratory tests; however, they ignore the consequence of the in situ stress effect on σcm [31]. When considering the influencing factors and limitations of traditional rock burst criteria, a comprehensive study was conducted based on the data that were related to the characteristics of the rock bursts that occurred during NJHEP construction, and a novel rock burst criterion was proposed [23]. This criterion utilizes the rock mass strength-stress ratio.…”

Section: Rock Burst Prediction Criteria For Neelum-jhelum Hydroelectrmentioning

confidence: 99%

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Impact of Construction Method and Ground Composition on Headrace Tunnel Stability in the Neelum–Jhelum Hydroelectric Project: A Case Study Review from Pakistan

et al. 2021

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During underground construction, the behavior of the ground is influenced by characteristics of the rock mass with situ stresses and ground water, cross section of the excavation area, excavation method, and the rate of excavation. These fundamental features are considered to ensure the support and stability of underground excavations and achieve long-term successful operation. However, the ground composition of the Himalayas hinders tunnel excavation, especially in case of mechanized tunneling; this causes time and cost overruns. This study has reviewed the recently completed Neelum–Jhelum Hydroelectric Project; the project complexities, geological environments involving significant overburden and tectonic stresses, and effects of the excavation method on tunnel stability were analyzed. The major challenges that were encountered during construction are discussed herein along with their countermeasures. An analysis of project-related data reveals that latest techniques and approaches considering rock mechanics were used to complete the project; the existing approaches and methods were accordingly verified and extended. Apart from ground composition, the excavation methods used play an important role in the occurrence of severe rock bursts. Thus, the findings of this study are expected to be helpful for future tunneling projects in the Himalayas.

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Section: Project Geology Detailsmentioning

confidence: 99%

Section: Rock Burst Prediction Criteria For Neelum-jhelum Hydroelectrmentioning

confidence: 99%

Impact of Construction Method and Ground Composition on Headrace Tunnel Stability in the Neelum–Jhelum Hydroelectric Project: A Case Study Review from Pakistan

et al. 2021

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“…In computing the ratio of the rock mass strength σ cm to the geostress, Ma et al [21] represented the geostress as the horizontal stress perpendicular to the tunnel axis. In the current study, the maximum stress σ max was still used to represent the geostress, considering the availability in practice and the comparability with the existing specifications (i.e., the code for hydropower engineering geological investigation, 2016).…”

Section: Rock Burst Estimation Based On Rock Mass Strengthmentioning

confidence: 99%

“…Wu et al [20] proposed a method to analyze the GSI and the disturbance factor of the rock mass and calculated the RMS based on this method. Ma et al [21] thereafter estimated the rock burst by a ratio of the H-B strength-based σ cm to the horizontal stress perpendicular to the tunnel axis. e traditional rock burst estimation method usually estimates the rock burst grades based on the ratio of σ c to σ max , and the estimated results are often different from the actual situation.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Rock Burst Grades Using Rock Mass Strength

Wang

et al. 2020

Advances in Civil Engineering

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The traditional rock burst estimation method is usually based on the σc (rock strength) in practice, while the actual occurrence of rock burst depends more on the structure and strength of the rock mass. In this work, the actual rock bursts occurred in a railway tunnel project in Western China, and the σcm (rock mass strength) was calculated by the generalized Hoek–Brown criterion. According to the actual situation of rock bursts, a modified rock burst estimation criterion using the ratio of σcm to σmax (maximum geostress) was proposed. The influence of randomness on the reliability of rock burst estimation criterion was considered. The estimation results based on the traditional and modified method were furthermore compared with those of the actual rock bursts. The results show that σcm calculated by the generalized Hoek–Brown criterion may be considered well in the rock type and strength, construction condition, and structure features of the rock mass; the estimation results of rock burst using the ratio of σc to σmax are quite different from the actual situation, while those using the ratio of the σcm to σmax coincided relatively with the actual rock bursts; the ratios of σcm to σmax, which are greater than 0.167, 0.066 to 0.167, 0.012 to 0.066, and less than 0.012, are corresponded to the slight, medium, strong, and violent grades of the rock bursts, respectively; the randomness of data selection has certain influence on the rock burst estimation criterion, but the variation range is small; the modified estimation criterion of rock burst proposed in this work has a good reliability. The results presented herein are important for tunnel construction and the prevention of rock burst in the high geostress areas.

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“…Rockburst is induced by the sudden release of elastic strain energy when the mechanical state of the surrounding rock or coal is unstable. is kind of energy release is usually violent, sharp, and associated with dynamic phenomena such as rock ejection, spalling, and slabbing [2][3][4]. is catastrophic disaster has caused a large number of casualties and property losses in underground mines [5,6].…”

Section: Introductionmentioning

confidence: 99%

Rockburst Monitoring in Deep Coalmines with Protective Coal Panels Using Integrated Microseismic and Computed Tomography Methods

Zhang

2020

Shock and Vibration

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In deep coalmines, longwall panels are subject to high static initial geostress andhigh dynamic stress caused by mining and tunnelling activities. Under the action of high static and dynamic stress, rockburst hazards are very likely to occur. To reduce rockburst risks, protective panels are commonly applied in deep coalmines. However, stress concentration in the protective coal panel often causes rockburst hazards in the gateway of the next longwall panel pending mining. To reduce such type of rockburst, this study firstly proposes a mathematic model to analyse the overall static stress distribution in the protective panel based on the mining practice in Longyun coalmine, Shandong Province, China. To evaluate the stress concentration caused by geological defects in the protective panel, a new rockburst evaluation index is proposed based on the computed tomography (CT) method. Finally, the extent of dynamic stress evolution caused by different working face advancing velocities is determined by microseismic monitoring. Results show that the areas with higher rockburst evaluation indexes are highly associated with the areas with large-energy microseismic events, indicating that the static stress concentration can be accurately identified by the CT method. A medium advancing velocity (4.0 m/s) is recommend during mining the longwall panel, which can ensure mining safety and improve mining productivity simultaneously. The integrated microseismic and CT monitoring methods can be used in other underground projects to guarantee construction safety and productivity.

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Novel rockburst criterion based on the TBM tunnel construction of the Neelum–Jhelum (NJ) hydroelectric project in Pakistan

Cited by 32 publications

References 19 publications

Impact of Construction Method and Ground Composition on Headrace Tunnel Stability in the Neelum–Jhelum Hydroelectric Project: A Case Study Review from Pakistan

Impact of Construction Method and Ground Composition on Headrace Tunnel Stability in the Neelum–Jhelum Hydroelectric Project: A Case Study Review from Pakistan

Estimation of Rock Burst Grades Using Rock Mass Strength

Rockburst Monitoring in Deep Coalmines with Protective Coal Panels Using Integrated Microseismic and Computed Tomography Methods

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