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Jul 01, 2021 This presentation is part of the series of presentations "Utility Tunnelling" and deals with the various types of shield machines, the removal of obstacles and possible errors in pipe jacking. |
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Underground pipelines and utilities are predominantly installed by using the tradition open-cut (i.e., cut and fill) method: a trench is dug, the lines are installed by constructing proper embankment or sheeting or using a trench box, and the trench is filled afterwards. In the face of the numerous challenges (e.g., urbanization, densely populated areas) as well as growing environmental consciousness, it is important to consider trenchless technology … |
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(Image: Manned techniques) (Image: Steerable techniques) Pipe jacking: |
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The components required for pipe jacking depend on the variant used to support the workface or convey excavated soil. However, the following key components are essential:
(Image: Schematic presentation of a pipe jacking - NEU) (Video: Pipe jacking in Bahrain) |
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View into the starting shaft. The individual components are clearly visible: the jacking pipe (1), the main press station consisting of the jacking cylinders (3) including all necessary hydraulic equipment as well as the thrust wall (4) and the thrust ring made of steel (2). (Image: View into the starting shaft - Arrangement for pipe jacking) (Image: Damage to the jacking abutment due to inadequate dimensioning - Jacking forces cannot be absorbed by … |
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A shield machine is a steerable shoring construction, in the protection of which the soil / rock on the working face is excavated manually, mechanically or hydraulically. It consists of at least two flexible connected steel pipe pieces, the front shield segment and the trailing shield segment, which is supported by the jacking pipe string. A distinction is made here between open and closed shields or shields with partial and full face excavation.… |
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(Image: Overview of shield machine types) |
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Open shields: Open shields do not have a pressure-tight seal between the working face and the subsequent pipe string. They are characterized by relatively good access to the working face and easy-to-use machine technique. (Image: Hand shields - Overall view of a hand shield (external diameter 2098 mm) [FI-Nishi]) (Image: Open shield) (Image: … |
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Aug 08, 2008
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Aug 08, 2008 Depending on the in-situ subsoil, the following excavation machines are usually utilized in these shield machines:
(Image: Shield machines with mechanical partial excavation - working face with natural support with reference to [FI-Herreb] [Image: S&P GmbH]) (Image: Shield … |
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Aug 08, 2008
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Aug 08, 2008
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Aug 08, 2008
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Aug 08, 2008
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(Image: Attention!) In order to excavate the soil or rock at the working face, the cutter head must be equipped with excavation tools adapted to the geotechnical conditions. The following excavation tools are available:
(Image: Excavation tools [Source: STEIN Ingenieure GmbH]) (Image: Massive wear on a cutting wheel … |
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Rippers are blunt tools inserted at right angles to the working face and usually have a square shape. Their purpose is the loosening of non-cohesive soils such as gravel, sand and silt, including the numerous intermediate variants, from their natural positions. Cohesive soils are kneaded if pick bits are used [Maidl94]. Rippers are commonly used as primary excavation tools only or together with disc cutters. (Image: Variants of rippers ) |
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