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Another representative of the SM-B type of shield machine is the LUNDBY method [FI-Skansb]. The balance of the earth pressure with this remote controlled variant is undertaken by two hydraulically adjustable and closable opening flaps (doors) situated … |
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Unscheduled changes of method by means of modification are carried out from the pipe string or from a specially excavated auxiliary shaft. Modification is work, cost and time intensive and can take several weeks. Because of the time lost, it may be necessary to carry out methods for speeding up and to take measures for temporary support or balance of the working face by means of soil stabilization. Unscheduled modification should be excluded as far … |
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An expected or scheduled change of method technology must be taken into account early on in the planning phase. In order to be able to undertake the changes in the shield machine in the starting or an intermediate shaft, the shaft is sunk at the transition point of the changed subsoil conditions. If modification in the shaft is not possible due to topographical or other reasons, then it is carried out in the protection of a specially built station … |
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In view of the difficulties, costs and time required for a scheduled change of method by means of modification, variable shield types have been developed which permit a change of the method technology to be carried out in a few working shifts, even in a few hours. The change can then take place at any desired jacking position [Tunnel01]. The investment costs for such a shield machine are usually greater as a change of method often also results in … |
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The Mixschild as an example for changing over from hydro to slurry shield and reverse is shown in Bild 9.2.2.8.4.1 and Bild 9.2.2.8.4.1. The change over from hydro to slurry shield makes a more effective application possible when a stable working face is present, e.g. in rock or firm to stiff and very stiff cohesive soils. It is achieved by closing the pipes for compressed air supply and return (10), the excavation chamber release of air (11), the … |
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(Image: Spoil conveying with shield machines with fluid supported and earth pressure balanced working face based on [Maidl01b]) In stable cohesive soils with a very stiff consistency (IC > 1.0), high cohesion and low water permeability and in rock, the EPB shield (SM-V5) can be operated with the same method technology without working face support in open method (SM-V1) [Maidl95c]. In this case, the working chamber is only partly filled. Because the … |
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A representative of this conversion is the EPB UNCLEMOLE (Bild 9.2.2.8.4.3) (Bild 9.2.2.8.4.3) (Bild 9.2.2.8.4.3) [FI-Isekib]. The conversion itself can be carried out immediately during jacking to suit the changing subsoil situation. The shield machine is utilized in the nominal size range DN/ID 1500 to DN/ID 3000. Because of its design also as a shield with fluid support, the EPB Unclemole possesses a cone crusher that is able to break up cobbles … |
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Despite many attempts, it has not yet been possible to develop a universal shield machine that is able to carry out jacking under all possible geological and hydrogeological conditions and jacking-specific limiting conditions (such as jacking distance, nominal pipe size, depth of cover, etc.) as well as taking economic, ecological, logistical and safety aspects into account. As has been seen in the previous sections, every type of shield has limits … |
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Shield machines with full-face excavation (SM-V) differ from those with partial excavation (SM-T) in that they process and loosen the whole working face in one working step by means of a rotating boring head equipped with corresponding excavation tools. The characteristic feature of these machines is the type of support for the working face (Tabelle 9.2) (Tabelle 9.2). |
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Sep 19, 2005 Trenchless Technology for Installation of Cables and Pipelines Shield machines for jacking pipes with cross sections deviating from the circular Because of its modular structure, the DPLEX shield jacking method (Developing Parallel Link Excavating Shield Method) [FI-DAIHO], permits shield jacking with circular, rectangular or arc shaped cross section (Bild 9.2.3.1). The removal of the soil at the working face is achieved by means of a correspondingly shaped cutting frame rotating eccentrically about crankshafts (Bild 9.2.3.1) (Bild 9.2.3.1) [Watan97] [Kashi97].
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Sep 19, 2005 Trenchless Technology for Installation of Cables and Pipelines Shield machines for jacking pipes with cross sections deviating from the circular
The shield machine from the Japanese Takenaka Ltd. [FI-Takan] … |
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According to EN 12336 [DINEN12336:1996], a shield machine is any machine for the excavation of tunnels, in which the excavation is carried out, either by hand, mechanically or hydraulically within the protection of a shield whereby the shield is self supporting and is driven with thrust and/or steering jacks. The feature of shield machines, also called shields, for pipe jacking, is that the thrust jacks (jacking cylinders) are situated not in the … |
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Intermediate jacking stations (IJS) also called interjack(s) (stations), consist of several jacking cylinders that are installed evenly distributed inside the protection of a special steel guide ring between the pipe end faces of two specially equipped jacking pipes; the interjack forerun pipe and interjack afterrun pipe (Bild 9.3) (Bild 9.3) (Bild 9.3) (Bild 9.3) (Bild 9.3).
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Sep 19, 2005 Trenchless Technology for Installation of Cables and Pipelines Use of lubricating and support media for reducing skin friction
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Sep 19, 2005 Trenchless Technology for Installation of Cables and Pipelines Use of lubricating and support media for reducing skin friction In two-phase jacking of non-man-accessible pipes it is easily possible in this nominal size range to use individual interim pipes or trailing shield segments in the 1st phase as so-called lubrication pipes by installing injection nozzles in them and thus also to achieve even lubrication over the pipe circumference for the whole of the jacking distance (Abschnitt 8.3.2). This is possible because these pipes are recovered in the 2nd phase and thus do … |
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Sep 19, 2005 Trenchless Technology for Installation of Cables and Pipelines Use of lubricating and support media for reducing skin friction (Image: Manual lubrication of the pipe string through individual injection nozzles distributed evenly about the circumference of the pipe and the pipe string [FI-Toyot]) The method of grouting by hand in a man-accessible pipe string can also be called manual lubrication. In this method, the lubricant is injected into the annular space by hand through injection nozzles distributed evenly about the pipe circumference and the pipe string by hand activation … |
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Sep 19, 2005 Trenchless Technology for Installation of Cables and Pipelines Automatic grouting through injection nozzles in the pipe string In long distance and curved jacking, automatic grouting of the bentonite suspension for continuous and certain lubrication of the pipe string (≥ DN/ID 800) represents the state of the technology. Automatic lubrication systems are characterized by good economics as the personnel that would be needed for this activity are not required [Schwa00]. In this case, the lubrication is carried out with regard to time, volume or pressure by means of specific … |
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Sep 19, 2005 Trenchless Technology for Installation of Cables and Pipelines Automatic grouting through injection nozzles in the pipe string (Image: T.B.K. system for lubricating the jacking string with reference to [FI-TBKa] [Image: S&P GmbH]) The sealing and stabilization of the borehole wall with the aid of lubrication and support media based on bentonite suspensions depends on the type of soil (particle size distribution, water permeability), stability of the borehole, length of jacking time, among others, and thus has only limited possibilities. To extend this limit and to be able … |
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(Image: SS MOLE method - longitudinal section [FI-Toyot]) The SS MOLE (SS = Super Slurry) [FI-Toyot] is a microtunnelling or shield machine with fluid supported working face and a pneumatic conveying system (Abschnitt 8.4.1.2). It consists of the boring and steering head or front shield segment and, depending on the nominal pipe size, of two or three joined articulated trailing shield segments (Bild 9.5.1). The dimensions are found in Tabelle 9.5.1 |
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(Image: ULTIMATE METHOD - arrangement of the articulations and steering cylinders with reference to [FI-Kidoh] [Image: S&P GmbH]) The ULTIMATE METHOD (Bild 9.5.2) [FI-Kidoh] works with fluid supported or earth pressure balanced working face in the nominal size range of DN/ID 800 to DN/ID 3000. Preferred areas of application depending on the distribution of the particles are shown in Bild 9.5.2 and Bild 9.5.2. This method is very similar to the SS MOLE (… |
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