Application of the NATM method in the road tunneling works in difficult geological conditions – The Carpathian flysch

Niedbalski, Zbigniew; Małkowski, Piotr; Majcherczyk, T.

doi:10.1016/j.tust.2018.01.003

Cited by 29 publications

(8 citation statements)

References 17 publications

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“…Many previous researchers put forward opinions on the irregular behavior of large deformation tunnel support. For example, Zbigniew et al [45] based on the Laliki tunnel in the Carpathian flysch pointed out that the expansive claystone content and steep dip of the strata are critical in this aspect, because they both lead to the shear displacements. However, based on the field observation in this paper, the dip of the strata is not steep, the rock is not expansive claystone and the expansibility of the rock is low, and hence it is not a common large expansive deformation.…”

Section: Discussionmentioning

confidence: 99%

Physical and Mechanical Characteristics of Soft Rock Tunnel and the Effect of Excavation on Supporting Structure

et al. 2019

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The problem of large deformation is very prominent in deep-buried tunnel excavation in soft rock, which brings serious potential safety hazards and economic losses to projects. The knowledge of deformation law and support measures is the key to ensure the rational design and safe construction in a large deformation tunnel of soft rock. This paper describes rock physical and mechanical tests and field monitoring is employed to investigate the cause and development process of large deformation in Dongsong hydropower station in Sichuan Province, China. The results show that the free expansion rate of the rock sample is 20.0%, the average expansion stress of the rock sample is 11.0 kPa, and the expansibility of the rock is low. Large deformation of surrounding rock mainly comes from the dilatancy effect with high geostress and relaxation deformation with weak support. Shotcrete sealing exposed surrounding rock, and early strength support avoiding water immersion are useful to deal with the three main factors (weathering, water and confining pressure) that affect the strength of surrounding rocks. The second lining applied in time can effectively limit the further development of stress and deformation of initial support, and prevent the cracking and large deformation of concrete. Clearance convergence is suggested to be the main monitoring work in construction, because of its advantages of intuitive results, easy quality assurance of instrument installation and high accuracy.

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Section: Discussionmentioning

confidence: 99%

Physical and Mechanical Characteristics of Soft Rock Tunnel and the Effect of Excavation on Supporting Structure

et al. 2019

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“…Regardless of the technique used, the average value of the contour roughness for the roofs is approximately 5% higher than that for sides (Figs 13 and 15). The above results may be influenced by the dense network of rock fractures occurring in the Carpathian flysch [27] (a quality aspect of the rock mass), in particular, by the value of an angle between the dominant direction of the fractures and the planned contour surface. It should also be remembered that parts of the rock mass weakened (detached) by the explosion remain in their place, within the sides, while they fell off from the roof.…”

Section: Contour Quality Within Sides and A Roof For Laser Profiling And Tls Techniquesmentioning

confidence: 99%

Evaluation of Tunnel Contour Quality Index on the Basis of Terrestrial Laser Scanning Data

Dybeł

Cieślik

2021

Studia Geotechnica Et Mechanica

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The Tunnel Contour Quality Index (TCI) is an index established by Kim and Bruland for an effective management of a tunnel contour quality. It is estimated on a basis of measurements of two contour profiles within a single blasting round, using a laser profiler. However, the representativeness of measurement results obtained that way for the assessment of a contour quality of the entire blasting round is disputable. Terrestrial laser scanning (TLS) technology, combined with available numerical surface modeling tools, enables development of three-dimensional models of a monitored surface. The article reports results of TCI calculations based on TLS data. The presented TLS technique is based not only on selected cross-sections of the tunnel contour but also on the description of the morphology of the tunnel contour surface. The case study concerns measurements of the “Mały Luboń” tunnel niche, located in Naprawa, Poland. The TCI values for three blasting rounds were determined in accordance with Kim and Bruland's guidelines and were compared to TCI values determined with the proposed TLS technique. On a basis of this comparison, it can be concluded that the results obtained with the TLS technique are more reliable and representative for description of the contour quality of the entire blasting round than results obtained with the laser profiling technique.

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“…Accounting for the stope works influence intensifies the rock pressure manifestations and can be attributed to a number of factors complicating the mining and geological environments of maintaining the extraction mine working. This is indicated by the normative document (Weijian & Genshui, 2017;Niedbalski, Małkowski, & Majcherczyk, 2018), according to which the dimensions of the dome of natural equilibrium and the load from the weight of rocks inside of it are constantly growing, as the longwall face approaches and recedes. This circumstance in the studied diagrams can be accounted for with another line of family 2, located above the rest, which makes it possible to use the above arguments for the preparatory mine working, which is influenced by the stope works.…”

Section: Interaction Of a Support In The Preparatory Mine Working With A Homogeneous Massifmentioning

confidence: 99%

Generalization of trends in the influence of geomechanics factors on the choice of operation modes for the fastening system in the preparatory mine workings

Kovalevska¹,

Zhuravkov²,

Chervatiuk³

et al. 2019

Min. miner. depos.

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Purpose. Substantiation of the mechanism of loading the preparatory mine working support to optimize its deformation-strength characteristics based on the calculation of the stress-strain state of the "massif -support" system. Improving the cost effective technologies for fastening and maintaining the preparatory mine workings.Methods. The analysis of the elements interaction modes of the "massif -support" system has been performed by the two-parameter diagram for optimizing the deformation-strength characteristics of the rock massif and the preparatory mine workings support using the research results of the stress-strain state of a system by means of finite element method. A comparison has been made of computational experiment with mine instrumental observations.Findings. The geomechanical model of the computational experiment on the choice of operation modes of the fastening system, as well as the methodology of the approach to optimize the process of interaction between the massif and the support have been substantiated. The analysis of search patterns for the rational deformation-strength characteristics of the fastening system in the preparatory mine working, taking into account the influence of the main geomechanics factors on this process, has been developed and performed.Originality. The patterns have been established of the geomechanics factors influence on the choice of rational operation modes of the load-bearing elements of the fastening system and the support in general based on research of the stress-strain state of the "massif -support" system. The optimization principles of interaction based on the analysis of a two-parameter interaction diagram have been substantiated.Practical implications. The wide perspective has been substantiated for strengthening the soft rocks in reusable preparatory mine workings with combined roof-bolting systems, which makes possible to realise the resource-saving conditions of maintenance. The calculations have been made with account of the optimization criteria for interaction of massif and support.

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Application of the NATM method in the road tunneling works in difficult geological conditions – The Carpathian flysch

Cited by 29 publications

References 17 publications

Physical and Mechanical Characteristics of Soft Rock Tunnel and the Effect of Excavation on Supporting Structure

Physical and Mechanical Characteristics of Soft Rock Tunnel and the Effect of Excavation on Supporting Structure

Evaluation of Tunnel Contour Quality Index on the Basis of Terrestrial Laser Scanning Data

Generalization of trends in the influence of geomechanics factors on the choice of operation modes for the fastening system in the preparatory mine workings

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