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With this type of machine, the spiral conveyors (auger rods) and cutting head form the auger string in that they are fixed together and are driven by means of a drive assembly installed on the jacking frame in the starting shaft (Bild 8.2.1.1). This type of drive can be used in the nominal pipe size range DN/ID 250 to DN/ID 500 [Becke96]. (Image: Microtunnelling with auger spoil removal in single phase jacking - Variant: driving the cutting head with … |
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(Image: Microtunnelling with auger spoil removal in single phase jacking - Variant: direct driving of the cutting head and separately driven spiral conveyor) In this variant, the cutting head and the spiral conveyors (auger rod string) are not connected to each other and are driven separately. The motor for driving the cutting head is situated in the trailing shield segment of the microtunnelling machine and the drive of the spiral conveyor, as with … |
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(Image: Microtunnelling with auger spoil removal) An overview of the sequence of microtunnelling with auger spoil removal and single phase jacking is shown in Bild 8.2.1. The spoil loosened at the working face with the aid of the cutting head is transported to the starting shaft by the spiral conveyor and is there collected in a spoil bucket. Using lifting tackle, this is lifted to the surface when full at determined intervals, usually after jacking … |
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An overview of the required basic equipment when using … |
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These method is used in cobble-free loose to densely compacted non-cohesive soils (classes LNE 1 to LNE 3 and LNW 1 to LNW 3) and very soft to soft and firm to stiff cohesive soils (classes LBM 1 and LBM 2 or LBO 1 and LBO 2) in the nominal sizes from DN/ID 250 to 500 [Becke96]. For the nominal sizes DN/ID 600 and DN/ID 800, the area of application extends further to the classes LNE 1 to LNE 3 or LNW 1 and LNW 2 as well as LBM 1 and LBM 2 [FI-Herreb]. |
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In the microtunnelling with a directly driven cutting head, a distinction is made between the standard cutting head and the rock cutting head. This type of machine is used in the nominal size range from 400 ≤ DN/ID ≤ 800. When using the standard cutting head, the area of application (compared to the microtunnelling with driving the standard cutting head with the spiral conveyor) is also extended to cobble-free, very stiff cohesive soils (LBM 3 and … |
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No further aid measures are necessary when installing a rotary vane lock at the end of the spiral conveyor (Bild 8.2.3.3.1) or a rotating feed apparatus (Bild 8.2.3.3.1). The use of sealing systems only cause unimportant pressure losses. During the necessary interruption of procedures of the conveying equipment, for instance in the course of installing a new jacking pipe in the starting shaft, the hermetic closure of the spiral conveyor end must … |
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A representative of this variant is the IRONMOLE TPS (Bild 8.2.3.3.2) [FI-Komat]. Here the pressure balance of the groundwater pressure up to 0.6 bar or 6 m head of water above pipe invert occurs only at one place with the aid of an inflatable ring shaped elastomer sealing system (called compressed air valve in the following) arranged in the spiral conveyer guide pipe in the trailing shield segment (Bild 8.2.3.3.2).
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This variant is used in the SANWA HORIZONGER method (Bild 8.2.3.2) (Bild 8.2.3.2) (Bild 8.2.3.2) (Bild 8.2.3.2) (Bild 8.2.3.2) [FI-Sanwaa]. The compressed air valve mentioned above is combined with a longitudinally movable cutting head with a sealing ring (Bild 8.2.3.3.3). In the withdrawn position, the sealing ring hermetically seals the spiral conveyor entry opening and thus permits easy installation of a new jacking pipe in the starting shaft. … |
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This variant, for instance in the SANWA PRESSTONE method, is provided with an eccentric cone crusher and is a variant of the HORIZONGER method modified for use in groundwater [FI-Sanwaa]. For maintaining the required supporting pressure at the working face, it uses a spade that is movable along the longitudinal axis at the end of the respective spiral in combination with the injection of a bentonite suspension in the region of the spiral conveyor … |
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Microtunnelling methods with auger spoil removal can only be used in saturated or water bearing soils to a limited extent. The reason for this can be found in the design of the conveyor arrangement, which, in the design of the auger string as well as the spiral conveyors, does not represent a closed system and therefore permits the flow of the groundwater from the working face to the starting shaft. According to manufacturer information, with cohesive … |
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According to ATV-A 125E [ATVA125:1996], the area of application of the microtunnelling with auger spoil removal ranges from nominal pipe size DN/ID 250 to DN/ID 1000 and for jacking distances up to 150 m [Eulen97] [Geres98] in cohesive and non-cohesive soils. They can only be used to a limited extent in groundwater without auxiliary measures (Abschnitt 8.2.3.3). To achieve controlled mechanical pressure balance of the working face, reference [Becke96] … |
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Microtunnelling with auger spoil removal, also known as (Bild 8.2) auger microtunnelling is characterized by single or two-phase jacking (Abschnitt 3) of pipes (Abschnitt 13) in soils (in exceptional cases also in rock mass) with … |
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As regards the jacking of the pipes, the method of operation of the single-phase microtunnelling method with hydraulic spoil removal corresponds in principle with the microtunnelling with auger spoil removal (Abschnitt 8.2). For geometrical reasons, use is made of the so-called slurry principle (Abschnitt 9.2.2.5) for the liquid pressure balance of the working face where the required pressure of the balance and conveying liquid (flushing fluid) is … |
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Most of the microtunnelling … |
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An overview of the required basic equipment for microtunnelling with hydraulic spoil removal is shown in Bild 8.3.1.2 and Bild 8.3.1.2. In principle, the required basic equipment for microtunnelling with hydraulic spoil removal consists of … |
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Microtunnelling methods with hydraulic spoil removal and standard cutting heads are used in cobble-free, loosely to densely compacted, non-cohesive and very soft or soft to very stiff cohesive soils in the nominal size range DN/ID 200 to 1200. An exception to this is in very soft to soft cohesive soils (classes LBM 1 to LBO 1) in the nominal size range DN/ID 1200 as the support of the working face can then no longer be ensured (Tabelle 8.3.1.3.1)… |
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Microtunnelling methods with hydraulic spoil removal and rock cutting heads are used mainly in the presence of cobbles and boulders (additional classes S 1 to S 4). In addition, utilization is also possible in the nominal size range DN/ID 300 to 1200 in all soil classes L without additional class S (Tabelle 8.3.1.3.1). However, because of sticking of the cutting head and the excavation tools (Abschnitt 9.2.2.5) and too little removal of spoil despite … |
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Rock cutting heads, because of their geometrical contraints can only be used of ≥ DN/ID 300 based on [FI-Herreb] [Becke96] under the following limiting conditions:
In rock with an uniaxial compressive strength > 100 N/mm2 (classes FD 4 and FZ 4), the … |
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Microtunnelling methods with hydraulic spoil removal are used in the nominal pipe size range from DN/ID 200 [Suzuk97] up to a clear width of 1200 mm (Abschnitt 3) in soils and rock with and without groundwater. The maximum achievable jacking distances depend on the nominal size and are between 120 m and 500 m (Tabelle 8.3.1.3). (Table: Maximum achievable jacking lengths with reference to the jacking pipe size [Kollm00] [FI-Rasa]) The minimum depth of … |
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(Image: Principle of the withdrawal technique of a microtunnelling machine with hydraulic spoil removal) It is not possible in all cases (e.g. in the later creation of drainage pipes in waste dumps and contaminated areas or the creation of pipe arches [Camp01]) to excavate target shafts, for instance, for the removal of microtunnelling machines. In such cases, only microtunnelling machines that are suitable for the jacking of blind borings can be … |
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The microtunnelling method with hydraulic spoil removal [ATVA125:1996] [Stein89g] [Stein96a] [Stein98d] (Bild 8.3) in EN 12889 [DINEN12889:2000] is also called slurry shield microtunnelling. It is characterized by single or two-phase jacking (Abschnitt 3) … |
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In the method with pneumatic conveying based on a suction plant, the spoil from the excavation and crusher chamber moves through an opening into a rotary vane lock arranged in front of the suction nozzle (Bild 8.4.1.1.1) (Bild 8.4.1.1.1). From there, with the aid of the air flushing medium, it travels through a suction line up to the surface to the preliminary separator where it is separated from the airflow (Bild 8.4.1.1.1) (Bild 8.4.1.1.1). The … |
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