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Feb 04, 2020 According to the latest state of the technology and in the absence of an appropriate calculation method, a constant modulus of elasticity is used for the pressure transfer ring in the structural verification process of planning a jacking measure. Due to the inevitable lack of precision this constant has to be chosen on the safe side. Thus, the structural calculation of the jacking pipes can only be a “snapshot“ of jacking, in which only one specific … |
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Feb 04, 2020 “A chain is no stronger than its weakest link” – if we apply this well-known saying to the chain “pipe string”, the weakest link would be the pipe joint. The central structural issue in pipe jacking is the transmission of jacking forces from pipe to pipe. With pipes made of reinforced concrete or vitrified clay, in particular, the pipe string does not bend continuously in curved jackings and in steering movements, but the “stiff” pipe remains largely … |
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Feb 04, 2020 The bigger the forces and the number and extent of the steering movements, the more the pressure transfer ring is loaded far beyond its limit of elasticity. This load results in irreversible plastic compressions that persist even after the pressure transfer ring is unloaded. Each pressure transfer ring is loaded and unloaded many times during a jacking measure. Furthermore, the angular deflection changes constantly. Thus, the pressure transfer ring … |
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Feb 04, 2020 (Image: Typical damages to jacking pipes due to overloading during jacking - Bild 1) (Image: Typical damages to jacking pipes due to overloading during jacking – Bild 2) (Image: Typical damages to jacking pipes due to overloading during jacking - Bild 3) (Image: Typical damages to jacking pipes due to overloading during jacking - Bild 4) (Image: Typical damages to jacking pipes due to overloading during jacking – Bild 5) (Image: Typical damages to … |
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Feb 04, 2020 A more accurate structural calculation of the pipe stress considering the non-linear stiffness behaviour of the pressure transfer ring is absolutely necessary to ensure a sufficiently high level of safety. The economic practicability must also be taken into account. Essential input parameters for a calculation of the pipe stresses from the engineering viewpoint are:
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May 19, 2011 This presentation is part of the series of presentations "Utility Tunnelling" and deals with the different materials of jacking pipes and the corresponding pipe joints. |
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Today, supply and discharge lines are still predominantly installed by using the open-cut method: a trench is dug, the lines are installed. Under the protection of an embankment or sheeting and the trench is filled afterwards. In the face of the numerous disadvantages as well as the citizens' growing environmental consciousness in the future it is urgently necessary to take trenchless technology into account much stronger than until today as an alternative … |
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Aug 04, 2008 (Image: Equipment, possible arrangement of the components on the construction site and space requirement (approximately L × W = 22.0 × 4.0 m) in microtunnelling with auger spoil removal - top view (on the model of the jacking of pipes DN/ID 600, pipe length 2.0 m)) The dimensions of the starting shaft are determined by the type of machine and the selected size and length of the jacking pipes. Today, use is made mostly of prefabricated reinforced concrete … |
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Aug 04, 2008 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 a pipe piece. The pressure at the working face is mechanically balanced by the cutting head or by means of the soil plug that is formed in the front section of the conveyor … |
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Aug 04, 2008 Possible measures for the application in groundwater-bearing soil:
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Aug 15, 2006 (Image: Microtunnelling with hydraulic spoil removal in single phase jacking) (Image: Basic equipment, possible arrangement components on the construction site and space requirements (ca. L × B = 35 × 4 m) for microtunnelling with hydraulic 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 hydraulic spoil removal is characterized by the jacking of pipes … |
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Aug 04, 2008 (Image: Basic equipment, possible arrangement components on the construction site and space requirements (ca. L × B = 35 × 4 m) for microtunnelling with hydraulic spoil removal - plan view (on the model of the jacking of pipes DN/ID 600, pipe length 2.0 m)) The dimensions of the starting shaft are determined by the type of machine and the selected size and length of the jacking pipes. Today, use is made mostly of prefabricated reinforced concrete … |
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Aug 15, 2006 (Video: Integrated high-pressure flushing system in the crusher space of the AVN microtunnelling machine) Video: Integrated high-pressure flushing system in the crusher space of the AVN microtunnelling machine with reference to [FI-Herrea] [Image: S&P GmbH]. This interactive object is only visible online. |
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