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May 04, 2020 (Image: Stone crusher arrangement of the UNCLEMOLE [FI-Isekib]) (Image: Eccentric cone crusher [FI-MGF]) (Image: Pipe-Replacer [FI-NLW] - Eccentric breaker disc; the coned breaker disc is placed eccentrically on the main drive shaft) |
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May 04, 2020 |
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(Image: Microtunnelling with pneumatic spoil removal) (Image: Equipment, possible arrangement of the components on the construction site and space requirements (approximately L x W = 34 x 4 m) in microtunnelling with pneumatic spoil removal - plan view (on the model of the jacking of pipes DN/ID 600, pipe length 2.0 m)) Method of operation and sequence Microtunnelling with pneumatic spoil removal on the basis of a suction plant is characterized by the … |
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(Image: Equipment, possible arrangement of the components on the construction site and space requirements (approximately L x W = 34 x 4 m) in microtunnelling with pneumatic spoil removal - plan view (on the model of the jacking of pipes DN/ID 600, pipe length 2.0 m)) The required internal diameter of the starting shaft is:
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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. From there, with the aid of the air flushing medium, it travels through a suction line up to the surface and to the preliminary separator where it is separated from the air-flow. The rotary vane lock separates the excavation and crusher chamber … |
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The spoil in the excavation chamber is pressed into the discharge pipe (DN/ID 50 (2 in)) and is transported from there with the aid of a further jet of air to a vacuum container on the surface (pressure plant). The separation between the pressurized excavation chamber and the discharge pipe is achieved by means of a so-called "control plate" - a plate with ten peripheral openings of 50 mm clear dimension acting on the principle of the rotary vane … |
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May 04, 2020
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May 04, 2020 |
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May 04, 2020 |
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Method of operation and procedure Microtunnelling with scraper spoil removal is marked by pipe jacking with the simultaneous excavation of soil at the work face by means of a cutting head and continuous or discontinuous soil removal with a scraper arrangement. One representative of this group is the Swedish LUNDBY method [FI-Skansb]. (Image: Microtunnelling with spoil removal by other mechanical means (spoil removal by a scraper arrangement)) |
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May 04, 2020 The principle is based on the jacking of a pipe open at its front (open shield without excavation tools) in which, in order to reduce the friction forces, the soil that has entered is transported mechanically at regular intervals of time by means of a scraper or skip arrangement to the starting shaft and from there is lifted to the surface with a special slit grab. (Image: Principle of the LUNDBY method with spoil removal by a scraper arrangement … |
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May 04, 2020 |
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May 04, 2020
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Microtunnelling methods with soil displacement differ in the design and mode of operation of the displacement and steering head. Examples of three different microtunnelling methods with soil displacement are:
(Image: PERIMOLE TPM 200 method for jacking pipes DN/ID 200 [FI-Isekib] - View) (Image: ACEMOLE PL 30 [FI-NTTb]) (Image: HERRENKNECHT AVB microtunnelling method with soil displacement [FI-Herreb]) |
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May 04, 2020 In the PERIMOLE TPM method [FI-Isekib], the cone-shaped displacement and steering head is divided into two. The cone point and cone rump rotate eccentrically in opposite directions about their common axis during jacking and in this way displace the soil [Wilhe99a]. (Image: PERIMOLE TPM 200 method for jacking pipes DN/ID 200 [FI-Isekib] - View) (Image: Displacement and steering head of the PERIMOLE method) |
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In the ACEMOLE PL 30 method (PL = Press-in Long Distance) [ [FI-NTTa]], the displacement and steering head consists of a closed blunt cylinder that is extended hydraulically for soil displacement and, if required for steering, can be angled a maximum of ± 1.5%. After completing the stroke, the pipe string and the microtunnelling machine are advanced by the jacking station by the amount of the stroke [ [Matsu96]]. (Video: Displacement- and steering … |
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May 04, 2020 Microtunnelling machines of the HERRENKNECHT AVB type possess a coned displacement and steering head at whose point a rotating three-spoked rim cutting wheel is arranged. (Image: HERRENKNECHT AVB microtunnelling method with soil displacement [FI-Herreb]) |
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May 04, 2020 |
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The jacking resistances consist of:
(Image: Penetration resistance and jacking force) |
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Skin friction is determined by:
The skin friction, which is decisive for a dimensioning of the main jacking station and the jacking pipes, can basically be influenced by an overcut and by filling the overcut with lubricant and support medium. (Image: T.B.K. system [FI-TBKa] - Injection medium (Polymer drilling fluid consisting of polymer and water)) (Image: Annular … |
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May 04, 2020
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Curved jackings and steering errors frequently induce additional, radially directed guiding forces between the pipe and the subsoil. These forces increase the frictional resistance. Since this resistance is dependent on the longitudinal force in the pipe string, it increases in the course of the jacking. The effect of repeated steering errors is particularly disadvantageous, because the single resistances do not sum up, but lead to disproportionate … |
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