Development of LDSMand HDSM Concept for Variable Density TBMs

Geological overview of the underground section of the Blue Line from Sungai Buloh to Kajang of the Klang Valley MRT Project in Kuala Lumpur, Malaysia Quelle/credit: Herrenknecht AG
Geological overview of the underground section of the Blue Line from Sungai Buloh to Kajang of the Klang Valley MRT Project in Kuala Lumpur, Malaysia
Quelle/credit: Herrenknecht AG
Challenges for tunnelling technology to bore through the karstic limestone in Kuala Lumpur, Malaysia; alternation between soft ground and hard rock (mixed-face conditions) Quelle/credit: Herrenknecht AG, Michael Straesser
Challenges for tunnelling technology to bore through the karstic limestone in Kuala Lumpur, Malaysia; alternation between soft ground and hard rock (mixed-face conditions)
Quelle/credit: Herrenknecht AG, Michael Straesser
Assembly of the first Variable Density TBM S-774 with an outside diameter of 6.6 m in the launching shaft at Cochcrane in Kuala Lumpur, Malaysia, in March 2013 Quelle/credit: TLB, Britta Schoesser
Assembly of the first Variable Density TBM S-774 with an outside diameter of 6.6 m in the launching shaft at Cochcrane in Kuala Lumpur, Malaysia, in March 2013
Quelle/credit: TLB, Britta Schoesser
Pressure gradients of the support pressure in the excavation chamber for LDSM and HDSM Quelle/credit: Herrenknecht AG, Michael Straesser
Pressure gradients of the support pressure in the excavation chamber for LDSM and HDSM
Quelle/credit: Herrenknecht AG, Michael Straesser
Density development of HDSM [g/cm³] based on an LDSM B1 5% through the addition of limestone powder [g/1l LDSM] Quelle/credit: TLB
Density development of HDSM [g/cm³] based on an LDSM B1 5% through the addition of limestone powder [g/1l LDSM]
Quelle/credit: TLB
Results of the injection tests (examples) Quelle/credit: TLB/Herrenknecht
Results of the injection tests (examples)
Quelle/credit: TLB/Herrenknecht
Comparison of the drainage times for HDSMs with densities of 1.5 t/m³ and 1.7 t/m³ consisting of the products B1 5% + GER limestone powder (blue line) and CBS2 5% + KL limestone powder (red line) Quelle/credit: TLB
Comparison of the drainage times for HDSMs with densities of 1.5 t/m³ and 1.7 t/m³ consisting of the products B1 5% + GER limestone powder (blue line) and CBS2 5% + KL limestone powder (red line)
Quelle/credit: TLB
Comparison of the Marsh times for 1 l suspension according to DIN 4127 for LDSM and HDSM consisting of the products CBS2 + KL limestone powder and B1 + GER limestone powder (red marked bars show suspensions, which did not run out of the Marsh funnel) Quelle/credit: TLB
Comparison of the Marsh times for 1 l suspension according to DIN 4127 for LDSM and HDSM consisting of the products CBS2 + KL limestone powder and B1 + GER limestone powder (red marked bars show suspensions, which did not run out of the Marsh funnel)
Quelle/credit: TLB
Comparison of the Bingham yield point determined with the rotational viscometer according to API 13B for LDSM and HDSM consisting of the products CBS2 + KL limestone powder and B1 + GER limestone powder Quelle/credit: TLB
Comparison of the Bingham yield point determined with the rotational viscometer according to API 13B for LDSM and HDSM consisting of the products
CBS2 + KL limestone powder and B1 + GER limestone powder
Quelle/credit: TLB
Comparison of the filter cake thickness from the filter press test at 7 bar for 7.5 min according to DIN 4127 for LDSM and HDSM consisting of the products CBS2 + KL limestone powder and B1 + GER limestone powder Quelle/credit: TLB
Comparison of the filter cake thickness from the filter press test at 7 bar for 7.5 min according to DIN 4127 for LDSM and HDSM consisting of the products CBS2 + KL limestone powder and B1 + GER limestone powder
Quelle/credit: TLB
Results of the carrying capacity tests for HDSM consisting of the products B1 + GER limestone powder and the additional aggregates Sand A (1–2 mm), Sand B (2–4 mm) and Gravel C (5.6–8 mm) (Quantity of sand in g/1.0 l suspension): Red = no carrying capacity; Green = carrying capacity Quelle/credit (2): TLB
Results of the carrying capacity tests for HDSM consisting of the products B1 + GER limestone powder and the additional aggregates Sand A (1–2 mm),
Sand B (2–4 mm) and Gravel C (5.6–8 mm) (Quantity of sand in g/1.0 l suspension): Red = no carrying capacity; Green = carrying capacity
Quelle/credit (2): TLB
Results of the carrying capacity tests for HDSM consisting of the products CB2 + KL limestone powder and the additional aggregates Sand KL (<1 mm), Sand KL (1.2–2.4 mm) and Sand KL (2.4–4.8 mm) (Quantity of sand in g/1.0 l suspension): Red = no carrying capacity; Green = carrying capacity Quelle/credit: TLB
Results of the carrying capacity tests for HDSM consisting of the products CB2 + KL limestone powder and the additional aggregates Sand KL (<1 mm), Sand KL (1.2–2.4 mm) and Sand KL (2.4–4.8 mm) (Quantity of sand in g/1.0 l suspension): Red = no carrying capacity; Green = carrying capacity
Quelle/credit: TLB
Scope of application of the tested HDSM for selected grading curves in the injection tests Quelle/credit: TLB/Herrenknecht
Scope of application of the tested HDSM for selected grading curves in the injection tests
Quelle/credit: TLB/Herrenknecht
Tunnelling modes of the Variable Density TBM Quelle/credit: Herrenknecht AG, Michael Straesser
Tunnelling modes of the Variable Density TBM
Quelle/credit: Herrenknecht AG, Michael Straesser

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...

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