LSC™ Elements

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Lining Stress Controllers (LSCTM) have been developed as special supporting measure for highly squeezing rock mass conditions. The primary tunnel lining is divided into several segments by longitudinal construction joints. The purpose of this segmentation is the ability to absorb large deformations occurring during tunnel driving in weak ground.

LSCTM steel elements are installed into these deformation joints. The elements have defined workload during compression so the primary lining is not damaged. DYWIDAG-Systems International (DSI) has long-time experience in the application of LSCTM elements, which have been successfully used for many projects.

Contents

Introduction

Introduction ........................... ...................................................................................... 3

Fields of Application ........... ......................................................................................... 4

Main Advantages ......................................................................................................... 4

System Description ...................................................................................................... 4

System Components ................................................................................................... 5

Technical Data ............................................................................................................. 5

Technical Characteristics ............................................................................................. 5

Installation Procedure (Conventional Excavation) ....................................................... 6

Further References ...................................................................................................... 6

3

■ Weak ground combined with high overburden

■ Fault zones (large displacements)

■ Swelling ground

■ Squeezing ground

■ Maintenance of supporting forces and optimum utilization of the load-bearing capacity of the primary lining

■ Controlled stress release and deformability

■ Steady increase of support resistance while undergoing large deformations

■ Rapid increase of support resistance in slowly increasing deformations

■ Avoidance of excessive tunnel liner overstressing

■ Custom-specific adaption of the deformation characteristics of LSCTM Elements in accordance with project requirements

■ The most effective Lining Stress Controller currently used in Tunneling

Compared to the strength of the primary lining, the load-bearing resistance of LSCTM Elements is dimensioned at a lower level. Thus, large deformations can be absorbed by LSCTM Elements before the tunnel lining is damaged. The optimum supporting effect is created by selecting the best suited LSCTM Elements and the proper number of compression bodies which determine the overall load-bearing resistance characteristics.

Single yielding elements are aligned between base plates. These plates fix the position of the yielding elements and limit LSCTM Elements towards the tunnel lining. Each yielding element has a factory-set imperfection where controlled deformations start in case of excessive loading.

Fields of Application

Main Advantages

System Description

4

■ Base plates

■ Yielding elements

■ Holding bars

The type, number and length of LSCTM Elements is adapted to the load-bearing capacity of the primary lining and the displacements measured at the tunnel wall

■ Load-deformation characteristics can be changed to permit an adaption of the support resistance

■ Project-specific customization of the LSCTM Element geometry

System Components

Technical Characteristics

Type Unit A-II/3 1) A-II/4 1)

Design load yielding elements Fp [kN] 700Number of yielding elements [#] 3 4

Design load yielding element Fp.total 2) [kN] 2,100 2,800Deviation load cycle to design load tolF [%] ± 15 %

Shortening required to reach the design load lp.min [mm] 60Length [mm] 800 - 1,000Width [mm] 250 - 350Height [mm] 430

1) Standard types in conventional Tunneling2) LSCTM Elements with alternative dimensions available on request

Technical Data

Fp tol

∆lp dl [mm]

F[kN]

5

Installation Procedure (Conventional Excavation)

1. Adjustment of LSCTM Elements between support segments

2. Temporary fixing in the installation position

3. Installation of additional reinforcement required for load transmission

4. Coverage or insulation of LSCTM Elements to ensure a full utilization of the compression space

5. Application of shotcrete lining

6. Removal of the coverage

■ Moritz, B. 1999, “Ductile Support System for Tunnels in Squeezing Rock” Doctoral Thesis, Department of Civil Engineering, Technical University Graz

■ Radoncic, N. et al, „Ductile support design“; Geomechanics and Tunnelling 2 (2009), No. 5, DOI: 10.1002/geot.200900054

■ Schubert, W. 2008. “Design of Ductile Tunnel Linings”; 42nd US Rock Mechanics Symposium and 2nd U.S.-Canada Rock Mechanics Symposium, San Francisco, June 29 - July 2, 2008

Further References

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Please note: This brochure serves basic information purposes only. Technical data and information provided herein shall be considered non-binding and may be subject to change without notice. We do not assume any liabilityfor losses or damages attributed to the use of this technical data and any improper use of our products. Should you require further information on particular products, please do not hesitate to contact us.

"ALWAG" (AM 952/79), "AT" (AM 6138/2003), "AT-SYSTEM” (AM 6139/2003), "DYWI®" (4197869), "LSC" (AM 4326/2008), "OMEGA-BOLT®" (3258282), "POWER SET" (AM 6163/2002), and "TUBESPILE" (AM 4328/2008) are registered trademarks of DYWIDAG-Systems International GmbH."Combi Coat®" and "CT-Bolt" are trademarks of Vik Ørsta AS.DYWIDAG-Systems International GmbH is a partner of Vik Ørsta AS.

EMEADYWIDAG-Systems International GmbHAlfred-Wagner-Strasse 14061 Pasching/Linz, AustriaPhone +43-7229-610 49 0Fax +43-7229-610 49 80 E-mail alwag@dywidag-systems.atwww.alwag.com

North AmericaDSI Underground Systems Inc.9786 S Prosperity RoadWest Jordan, UT 84081, USAPhone +1-801-973 7169Fax +1-801-973 7172E-mail dsiunderground@dsiunderground.comwww.dsiunderground.com

South AmericaDSI Chile Industrial Ltda. Las Encinas #1387, Valle GrandeLampa, Santiago de Chile, ChilePhone +56-2-596 96 20Fax +56-2-596 96 69E-mail informaciones@dywidag-systems.clwww.dsi-chile.com

APAC/ASEANDYWIDAG-Systems International Pty. Ltd.25 Pacific HighwayBennetts Green, NSW 2290, AustraliaPhone +61-2-49 48 90 99Fax +61-2-49 48 99 56E-mail dsi@dywidag.com.auwww.dsiminingproducts.com/au

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