Development of LDSMand HDSM Concept for Variable Density TBMs

The capability to vary the density of the support medium between bentonite suspension and remoulded earth depending on the currently excavated ground is the essential feature of the Variable Density TBM (VD-TBM) from Herrenknecht. Especially for this type of machine, a support medium with an increased density has been developed, which reliably covers the transition from fluid to pasty – the High Density Support Medium (HDSM). On their first application for the Klang Valley MRT-Project in Kuala Lumpur, the VD-TBMs bored through karstic limestone in mixed face conditions with hard rock and soft ground. With the aid of the HDSM, the face support can be reliably maintained in otherwise problematic geology.

1 Introduction

Mechanised tunnelling in highly permeable ground with extremely heterogeneous geology along the alignment demands that the support medium used can reliably transfer the support pressure to the tunnel face.

Basically, the so-called multi-mode TBMs, which can be driven both in earth pressure and slurry support modes, are available for use in very changeable ground conditions. The changeover from earth pressure to hydro mode does however demand a technically elaborate conversion, which only permits the economic use of such machines in special cases. For the Klang Valley Mass Rapid...

Related articles:

Issue 2017-03

Tunnelling in Malaysia

In Malaysia, tunnelling took on an important change in 2003 when there was an acute need to address major flooding issues in the city of Kuala Lumpur. With the city densely built up to the brims, the...

more
Issue 2020-02 Thailand

Orange Line Metro Project Bangkok: Breakthrough of the Westbound Tunnel on Contract E3

In January 2020, TBM manufacturer Terratec joined workers and officials in celebrating the breakthrough of the 6.39 m diameter S70 EPB machine by contractor Italian-Thai Development PCL (ITD) on one...

more
Issue 2011-03

Additives to master major Permeabilities for EPB and Slurry TBMs

1 Background High permeabilities entail the risk that perhaps it is not possible to secure the required support needed for the face during the drive as well as in the case of compressed air accesses....

more
Issue 2015-07 Germany

Completion of Tunnelling Work for Berlin‘s new U5 Line

Upon reaching its final position at the Brandenburg Gate on October 14, 2015 the Mixshield “Bärlinde” has successfully completed its mission in Berlin. Behind the tunnel boring machine (TBM) are...

more
Issue 2013-07

ZERNA Planen und Prüfen

Underground route alignments for developing road and rail networks represent a decisive prerequisite for solving transportation problems. They enable traffic to flow directing it to where it is...

more