Evaluation of higher capacity segmental lining systems when tunnelling in squeezing rock

Mezger, Florence; Ramoni, Marco; Anagnostou, Georg; Dimitrakopoulos, Angelos; Meystre, Nicolas

doi:10.1016/j.tust.2017.02.012

Cited by 19 publications

(6 citation statements)

References 11 publications

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“…Chapter 2 was presented in Mezger and Anagnostou (2015). Chapters 14 and 15 were published in Mezger et al (2017) and Mezger et al (2018), respectively, under consideration of the comments and suggestions of Dr. Marco Ramoni, who helped to improve the papers (on the basis of his own doctoral thesis). These chapters have also been presented on several occasions (Mezger et al 2015b, Mezger et al 2015a, Mezger et al 2016.…”

Section: Publicationsmentioning

confidence: 99%

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On the variability of squeezing behaviour in tunnelling

Mezger¹

2020

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The magnitude of squeezing deformations in tunnelling often varies over short distances, even if there is no obvious change in the construction method, in the depth of cover, in the lithology or rock structure. As long as the reasons for the variability are not known, the tunnelling-induced convergences cannot be predicted with sufficient reliability. Reliable predictions, however, are important for determining the temporary support or the excavation diameter. Otherwise, large-scale tunnel repairs may be necessary, which can cause delay and additional costs due to remedial actions as well as due to the enforced interruption of other operations in progress at the same time. The analysis of different case studies concerning the AlpTransit project shows that the squeezing variability can be traced back to the heterogeneities in the rock mass at different scales as well as the variation of the orientation of the planes of anisotropy (bedding or schistosity) to the tunnel axis. In order to improve safety and economy of tunnel construction in squeezing ground, the influence of these factors on the convergences was determined quantitatively (by means of analytical solutions or numerical modelling), so that they can be used as indicators during construction for the timely identification and prediction of the squeezing behaviour. Particular attention was paid on factors, whose variation, even if small, may affect the convergences sensitively . Based on these quantitative investigations, design aids were developed, which should help the project engineer to estimate and better understand the variability of the squeezing intensity. The squeezing variability also concerns TBM tunnelling: In contrast to conventional tunnelling, shielded TBMs are particularly vulnerable to squeezing due to the very limited space available. Therefore, in order to better deal with the squeezing variability in TBM tunnelling, different (stiff as well as deformable) lining options were discussed.

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Section: Publicationsmentioning

confidence: 99%

“…This chapter has been published in: Mezger, F., Ramoni, M., Anagnostou, G., Dimitrakopoulos, A., Meystre, N. 2017. Evaluation of higher capacity segmental lining systems when tunnelling in squeezing rock.…”

Section: Lining Systemsmentioning

confidence: 99%

On the variability of squeezing behaviour in tunnelling

Mezger¹

2020

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“…Compared with single-layer lining and double-layer lining, the materials of the new composite lining structure are more diverse and the force transmission forms are more complex. There is a still lack of relevant research on force transmission among different layers of lining and the mechanism of load sharing (Mezger et al, 2017;Dong et al, 2021;Huang et al, 2021;Zhang et al, 2021;Zhou et al, 2021). In the past, it was seldom used to analyze the influence of structural parameters of "steel lining -SCC-segment" new composite lining by establishing an analytical model and analytical calculation method.…”

Section: Introductionmentioning

confidence: 99%

Study on Parameter Influence of New Composite Lining of Water Conveyance Tunnel Under High Internal Water Pressure

Zhu

Liu

2022

Front. Earth Sci.

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A new type of composite lining structure consisting of segments, steel pipes, and concrete lining can be adopted in the water conveyance tunnel to bear large internal water pressure. However, there is still no effective analysis model and calculation method for the parameter influence effect of this new composite lining. In this paper, the load structure method and the elasticity theory are adopted, the stress analysis model and theoretical calculation method of a new type of composite lining of water conveyance tunnel are given, and the influence law of lining structure parameters is studied. Each part of the shield assembled lining is regarded as a stressed spring, and a formula for calculating the equivalent elastic modulus of the overall structure at the joint of the lining under partial tension and partial compression is given. The stress and deformation of each layer of lining are deduced based on the theory of thick-walled cylinders. According to the actual project, the rationality of the calculation method is verified by comparing the results of finite element analysis, and the influence of the thickness of intermediate concrete lining and inner lining parameters on the distribution of force transmission among lining layers is further analyzed. The results show that the radial displacement and circumferential stress of each layer of lining structure decrease with increasing the thickness of the concrete lining. The larger the elastic modulus of the inner lining material is, the smaller the radial displacement of each lining structure will be, but the circumferential stress of the inner lining will increase. In addition, when the thickness of the steel pipe lining is reduced or the internal water pressure is increased, the circumferential stress and radial displacement generated by the inner lining will increase. This analysis model and method considering the deformation coordination relationship solves the problem of setting the parameters of the lining structure and has obvious advantages in the calculation of the stress and deformation of the new composite lining water conveyance tunnel structure, which can provide a theoretical basis for related engineering design.

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“…In addition, since the long-term creep deformation characteristics of soft surrounding rock will lead to large deformation disasters, it is very important to maintain the structural integrity of soft rock tunnel lining in a cracked state [5]. Caratelli et al [6] proposed that fiber shotcrete can replace traditional reinforced concrete as a tunnel lining material, mainly because the existence of fiber improves the deformation capacity of lining and controls the opening degree of lining cracks.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Load Bearing Characteristics of Steel Fiber Reinforced Concrete Lining in the Soft Surrounding Rock Tunnel

Cui

Wang³

2020

Advances in Civil Engineering

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Tunnels in soft rock with high ground stress will encounter the problem of large deformation of surrounding rock. The study of new high-performance tunnel lining materials is of great significance to improve the safety of tunnel excavation in soft rock with high ground stress. In this paper, the bearing characteristics of the plain concrete, the reinforced concrete, and the steel fiber reinforced concrete lining are studied by the indoor model experiment. By extracting the displacement and stress data of typical parts of lining, the bearing characteristics of the steel fiber reinforced concrete lining are analyzed and summarized. The test results show that the initial crack load and ultimate load of the steel fiber reinforced concrete lining are significantly higher than those of the other two materials, and the crack development path is more tortuous, and the number of cracks is greater. Steel fiber can improve the bearing capacity and deformation capacity of the lining structure so that the failure mode of the lining structure changes from brittle shear failure to ductile bending failure. It is concluded that steel fiber reinforced concrete can improve the toughness of lining. Because of its excellent mechanical properties, steel fiber reinforced concrete can completely replace the conventional reinforced concrete as a new lining material for soft rock tunnel. The above research results are of great significance to the design and construction of tunnel lining in the soft surrounding rock.

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Evaluation of higher capacity segmental lining systems when tunnelling in squeezing rock

Cited by 19 publications

References 11 publications

On the variability of squeezing behaviour in tunnelling

On the variability of squeezing behaviour in tunnelling

Study on Parameter Influence of New Composite Lining of Water Conveyance Tunnel Under High Internal Water Pressure

Experimental Study on Load Bearing Characteristics of Steel Fiber Reinforced Concrete Lining in the Soft Surrounding Rock Tunnel

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