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The amount of water in the hose is dimensioned depending on the project in such a way that the maximum possible jacking force is achieved while ensuring the necessary deviation ability. CoJackHydra allows for significantly higher jacking forces than conventional pressure transfer rings, especially in tight curves or in curve combinations (S-curves) in the jacking alignment. Visual description of the steering procedure:
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1. Higher permissible jacking forces particularly in curves
2. Better angular deflection of the pipe joints
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The hydraulic joint is supplied as single or multiple circumferential closed rings. The position is fixed without drilling or gluing to the pipe end. There must be no recesses or bevels on the inside of the jacking pipe or on the concrete edges of the pipe end. Any recesses on the pipe end faces must not extend to the inner or outer surface of the pipe. This also applies to the concrete on the steel collar to avoid leakages. The pocket for receiving … |
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Mar 17, 2006 Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space
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Mar 17, 2006 Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space
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Mar 17, 2006 Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space
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Mar 17, 2006 Renovation: Lining with Continuous Pipes - Part III - Method Variants with Annular Space
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The earth structural stability analysis includes:
The first two assessments that only apply to the shafts reaching … |
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Aug 05, 2008
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Jan 25, 2005 The jacking resistances consist of:
(Image: Penetration resistance and jacking force) |
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Aug 05, 2008 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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Aug 05, 2008
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Jan 25, 2005 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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Aug 05, 2008 Thus, besides the creation of an overcut and the lubrication and support of the associated annular gap from DN/ID 800 (32 in), intermediate jacking stations can be installed from DN/ID 500 (20 in) for sectional or cyclical jacking of the whole pipe string in order to reduce the jacking force. New developments in past years have aimed at, among other targets, reducing the individual forces connected with jacking still further and making them more calculable. … |
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In engineering measurements in general as well as in trenchless installation based on the principle of pipe jacking, horizontal or positional measurements, as well as vertical or height measurements are carried out preferably with optical instruments. In trenchless installation, therefore, the following measurement instruments or apparatus are used:
(Image: Principle and structure of the theodolite [… |
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The theodolite is an instrument for measuring horizontal and vertical angles . Its main components are the upper body rotating about the vertical axis, with the vertical graduated dial, the telescope rotating horizontally on a hinge pin, the lower body with the horizontal graduated dial as well as arrangements for reading the graduation divisions for levelling (equal to vertical setting of the vertical axis) and for centring [Deuml80]. (Image: Principle … |
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(Image: Directional laser) In the case of trenchless installation, mostly gas lasers (helium-neon) with a capacity of 1 mW to 5 mW are used. The acquisition of the target point of the laser beam on the target board can be carried out by means of the following method:
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The coupling of a directional laser with a theodolite results in the laser theodolite [Colli84]. In this case the laser beam replaces the optical beam. It is beamed through the telescope and projects the light point on the target board. The laser theodolite can provide directions in space. Also, by rotating the theodolite about the vertical axis, the generation of horizontal and vertical levels is possible. (Image: Laser theodolite (PENTAX ETH-120 … |
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For the determination of inclination and roll angles of the microtunnelling or shield machine, two electronic inclination measuring instruments set at 90° (dual-axis inclinometers) based on spirit levels (a reference point is provided by a fluid horizon) or micro-mechanical pendulums are generally utilized. The automatically acquired changes of angle are converted into digital or analogue output signals in the sensor unit and passed on to the central … |
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