Concrete Segmental Lining Research Articles

Development of a prestressed and precast concrete segmental lining

Prestressed & precast concrete segmental lining (P&PCSL) is used for shield tunnels. Its primary feature is that it integrates segments into one ring by introducing prestress in the tunnel circumferential and longitudinal directions. Introducing prestress enables the elimination of bolt joints and reduces the volume of reinforcement, thus reducing the manufacturing cost of precast concrete segments. It also enables quality improvement and labor saving in lining and provides greater adaptability for tunnels with large diameter, where deformation due to dead load is a problem. The P&PCSL has been implemented in three construction projects after undergoing various performance tests and workability verification tests.

Developments in segmental concrete linings for subway tunnels in Belarus: P. Yurkevich, Tunnelling & Underground Space Technology, 10(3), 1995, pp 353–365

Developments in segmental concrete linings for subway tunnels in Belarus: P. Yurkevich, Tunnelling & Underground Space Technology, 10(3), 1995, pp 353–365

STOREBAELT EASTERN RAILWAY TUNNEL: DESIGN.

This paper describes the design of the 8km long eastern railway tunnel of the Storebaelt (Great Belt) crossing in Denmark. Conceptual design was carried out in 1986, and several options were considered. Tender design was conducted in 1987-88, for two tunnel options. The contract was awarded for the bored tunnel option, designed by the Mott McDonald Group. The structures include: (1) earthworks, approach ramps, and cut-and-cover tunnels at each end; (2) twin 7.7m diameter circular bored tunnels; and (3) 31 4.5m diameter cross passages for equipment and emergency evacuation purposes. Site investigations showed complex ground conditions; the rocks include: glacial clay tills with layers of silt and sand, marl with fissured and jointed zones, and boulders of granite and gneiss. In anticipation of these geological conditions, four sophisticated earth pressure balance machines (EPBMs) were specified for the tunnel boring. The design of the main components of the project, including the mid-point drainage sumps, is discussed. For the first time in the tunnelling industry, it was decided to use fusion-bonded epoxy-coated reinforcing cages for the precast concrete segmental tunnel linings. Two-dimensional finite element ground/lining analyses were conducted for the main tunnel lining.

Steel fibre developments in South Africa

This article discusses an extensive South African research and development study of steel fibre reinforcement for precast concrete lining segments. The study developed a suitable concrete mix for a pressurised water tunnel in South Africa, using two different types of fibre, Dramix and Ferro-Fibres. It also included full-scale production in the on-site casting factory, and full-scale testing of both steel fibre reinforced concrete (SFRC) and bar-reinforced segments. Several of the segments, built into the tunnel, are fitted with instruments for continuous monitoring during segment production, handling and tunnelling operations; they will also provide for long-term on-site observation. The research study had three stages: (1) development of an SFRC mix, also suitable for the batching plant; (2) full-scale testing of SFRC and bar-reinforced segments using an on-site test rig; and (3) testing of complete rings as part of the permanent works. As a result, a form of SFRC segmental lining was found, which met all the design criteria and was significantly cheaper than the bar-reinforced design. Such SFRC segments also had some other advantages over bar- reinforced segments.

Developments in segmental concrete linings for subway tunnels in Belarus

The author reviews three developments in the design and manufacture of segmental concrete linings used for subway stations in the C.I.S. (Commonwealth of Independent States: formerly the Soviet Union): (1) in-situ concrete linings used in constructing subway stations incorporating permanent load-bearing diaphragm walls; (2) versatile integrated sections of precast reinforced concrete linings used in construction of rectangular cut-and-cover tunnels; and (3) plastic waterproofing coatings for precast reinforced concrete lining segments used in construction of bored tunnels.

Design and construction of a segmental lining for a machine-bored tunnel: Delivery tunnel North, Lesotho highlands water project

The 21-km-long Delivery Tunnel North for the Lesotho Highlands Water Project is split into two main tunnel drives of 8 km and 11 km lengths. The tunnel is located in the sedimentary rocks of the upper Karoo series with cover of up to 350 m. The rock units comprise claystones, siltstones and sandstones. In the poorer geology, early support of the tunnel periphery is essential. The method of tunnel construction involves excavation by a TBM and the simultaneous erection of a precast concrete segmental lining that provides both rock support and a final tunnel lining. The segmental lining is designed and constructed as part of an integrated excavation/support/lining system. There are three types of segments, differentiated by the amount of steel reinforcement. The distribution of the different segment types along the tunnel, relative to the geological conditions and depth of cover, will be optimized by monitoring of the performance of the lining during the construction period. Le canal d'écoulement nord du Lesotho Highlands Water Project, long de 21 km, est divisé en deux tunnels principaux de 8 et 11 km. Ce tunnel se situe dans les roches sédimentaires des couches supérieures de Karoo, avec une couverture atteignant 350 m. Le terrain se compose de roches argileuses, de silt et de grès. Lorsque les conditions géologiques sont difficiles, il est essentiel de mettre en place un soutènement à la périphérie du tunnel. La méthode de construction utilise un TBM et la mise en place simultanée de voussoirs en béton préfabriqués, qui assurent à la fois le soutènement de la roche et le revêtement définitif du tunnel. Le revêtement en voussoirs est conçu et construit comme partie du système intégré creusement/soutènement/revêtement. Il existe trois types de voussoirs, différenciés par le volume d'armature métallique. La distribution des différents types de voussoirs le long du tunnel, en fonction des conditions géologiques et de la hauteur de couverture, sera optimisée par le contrôle des performances du revêtement au cours de la période de construction.

Precast concrete segmental linings — practical considerations : Tiedemann, H R; Parker, H W; Hansmire, W H Proc 1987 Rapid Excavation and Tunnelling Conference, New Orleans, 14–17 June 1987V1, P87–95. Publ Littleton: Society of Mining Engineers, 1987

Precast concrete segmental linings — practical considerations : Tiedemann, H R; Parker, H W; Hansmire, W H Proc 1987 Rapid Excavation and Tunnelling Conference, New Orleans, 14–17 June 1987V1, P87–95. Publ Littleton: Society of Mining Engineers, 1987

Design of precast concrete segmental tunnel linings

Two main items are developed to be borne in mind by designers of segmented tunnel linings - that the process of tunnelling involves a complex redistribution of stress around the excavation as it proceeds and second the inter-relationship between the loads and deflections to which the lining is subjected during construction and the final state stresses following consideration of the structure/ground interaction.

Baltimore Region Rapid Transit System Use of Precast and Prestressed Concrete

The author presents an overview of Baltimore, Maryland's new rapid rail transit system. Particular attention is given to the precast concrete segmental tunnel lining, the prestressed concrete aerial structure girders, and the precast and prestressed concrete wall and roof panels for some of the auxiliary buildings.

Ground-lining pressure distribution and lining distortion in two tunnels driven through stiff, stony/laminated clay

This article describes the design, construction, and calibration of a hybrid electro-hydraulic type of earth pressure cell and the subsequent use of these cells for the measurement of radial ground pressures acting on concrete segmental tunnel linings at two locations in mixed clayey ground in north-east England. Also described is an accompanying programme of lining distortion measurement. The tunnels studied were 3.20 m dia. at depths of 11.77 m and 12.39 m to the crown. Terminal ground-lining interaction pressures were found to be almost uniformly distributed about the tunnel cross-section, these recorded pressures being one-half the theoretical maximum over-burden pressure calculated on a gamma z basis. Furthermore, these ultimate pressures were achieved after a period of only 7-8 days following lining erection and grouting-up. Lining distortion measurements support these observations. This rapid stabilisation of ground pressure at the lining contact contrasts with a much more protracted on-going pressure build-up and lining distortion reported by some other workers for different ground conditions, but is is certainly consistent with contractual experience which suggests that tunnel secondary linings could be safely erected, with little risk of brittle fracture, much earlier following primary lining construction that has hitherto been considered prudent. /Author/

Support of tunnels in rock : Farmer, I, Univ. Newcastle-Upon-Tyne, GB 4F, 2T, 13R Ground Engng, V9, N4, 1976, P29–32

This review is concerned with the 11 papers on the general subject area of support and lining design in tunnels in rock presented at the Tunnelling '76 Conference held in London, March 1-5, 1976. The conference included preliminary reports on two major tunnelling experiments--the kielder water scheme experimental tunnel, and the Phase II trial tunnels for the channel tunnel project. In discussing these two schemes the author refers to a paper that described the results of ground and lining strain measurements and compared the performance of different lining and support systems in a fissile shale; a paper that described lining instrumentation to investigate the performance of concrete segmental linings in chalk; a paper that described the ground instrumentation installation for the channel tunnel project; and a similar investigation to determine the radial pressure acting on cast-iron tunnel linings in an underwater tunnel in coal measures in rock. The extent of yield zones around tunnels, the deformation during yielding and the restraint offered by and imposed on tunnel linings is discussed. /TRRL/

Isar tunnel has innovative concrete segmental lining. Advance in technique for Munich's U-bahn : 10F UNDGR. SERVICES, V3, N2, 1975, P32–35

Isar tunnel has innovative concrete segmental lining. Advance in technique for Munich's U-bahn : 10F UNDGR. SERVICES, V3, N2, 1975, P32–35