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A special solution for microtunnelling with nominal sizes of jacking pipes up to a maximum of DN/ID 800 is the closed pressure chamber (Bild 12.8.2.2.2) (Bild 12.8.2.2.2) (Bild 12.8.2.2.2) (Bild 12.8.2.2.2) (Bild 12.8.2.2.2) (Bild 12.8.2.2.2). This closed pressure chamber is integrated into the shaft face from open sinking shafts, which are made of prefabricated reinforced concrete shaft rings (Abschnitt 12.6.2.2) (Abschnitt 12.8.1.4), by the factory. |
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(Image: Open pressure chamber welded to the inside of the shaft) Open pressure chambers welded into the shaft find particular application in sheet pile linings (Bild 12.8.2.2.3). The pressure chamber is sealed to the inside of the shaft by means of a steel box open welded to the sheet pile wall and open at the top. The top edge of the steel box must be above the maximum level of groundwater to be expected. The opening of the pressure chamber to the … |
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For pipe jacking of larger … |
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When using closed sinking shafts (Abschnitt 12.6.1) as starting or target shaft, it is feasible at the exit and entry phases to use the existing compressed air equipment (Bild 12.8.2.3). In this case, the pressurized shaft acts as a compressed air chamber for supporting the in-situ groundwater pressure when opening the exit or entry opening. The exit and entry openings are previously created during the construction of the reinforced concrete sinking … |
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Decisive for the size of the total earth or water pressures are the soil characteristics of the in-situ soil and the depth of the groundwater level. Should information on the earth characteristics from a geotechnical report (Abschnitt 4.5.2.5) not be available, the values must be taken from DIN 1055 [DIN1055c] or the "Empfehlungen des Arbeitsausschusses Ufereinfassungen" (Recommendation of the Working Committee on Banks (of rivers)) [EAU1990] (Tabelle … |
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When dimensioning the individual lining elements, account must be taken of the final condition as well as all construction phases of their installation and possible removal [Weiße75b]. The respective permissible stresses of the individual lining elements must be taken from the "EAB - 100" [EAB100] and DIN 4124 [DIN4124:2002]. Particular conditions must be met in the manufacture of types of linings that can be used universally and are re-usable. They … |
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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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The jacking forces that alternate between zero and the greatest load are transferred by the jacking cylinders through the abutments either, in unlined shafts directly or, for lined shafts indirectly into the lining wall and through its inherent stiffness into the subsoil. The soil stresses are the result of the size of the jacking force, the shaft depth, the soil properties and the geometric dimensions of the abutment. In the interest of a better … |
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Even today, there are neither national nor European standards for general requirements of jacking pipes independent of the type of pipe. A first attempt at this the EN 12889 [DINEN12889:2000] formulated in an extremely restricted form in Section 5.2 ",Pipes and joints" for drains and sewers. According to EN 12889 [DINEN12889:2000], "the installation shall not commence before the following criteria have been agreed between the specifier and installer. … |
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All parts of the pipeline including the pipe joints and sealings must be designed, produced and examined according to the objective to guarantee the tightness during the construction works (construction state) and the whole planned service life (operation state) taking the longterm properties of the sealing medium as well as potential movements of the pipe joints under the respective loads into consideration. The joints, for instance, of jacking pipes … |
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The possibility of transferring longitudinal forces in the jacking pipe string are greatly affected by the type of pipe joint and the pipe material. There is no universal solution but there are strong dependencies between the type of operation, the material and the construction measures of the pipes, on the one hand, and the type of pipe joint on the other hand. For this reason, the different joints for jacking pipes will be discussed in the following … |
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Concrete jacking pipes: to DIN V 1201 [DIN1201] and EN 1916 [DINEN1916:2003] which replace DIN 4032 are used mostly for unmanned jacking in the nominal size range < DN 1000 (Tabelle 13.3.1.1). (Table: Minimum wall thicknesses and minimum crushing strength of unreinforced FBS concrete pipes with circular cross sections without foot, strengthened walls (KW) and jacking pipes [FBS04]) As regards the design of the pipe joints and corrosion resistance, … |
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Special attention must be paid to corrosion resistance of cement-bound materials against attacks by sewage and influences of soil and groundwater. Limiting values for corrosion stresses by community sewage are given in Tabelle 13.3.1.2.1. When they are adhered to, then a service life for sewers that correspond to the LAWA guideline [LAWA93c] of 50 to 80 (100) years can be expected . For the case that the limiting values in the sewage or of biogenic … |
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According to EN 1916 [DINEN1916:2003], jacking pipes for gravity pipelines of concrete, reinforced concrete and steel fibre concrete must possess in-wall flexible nonrestrained joints either with a guide ring (in EN 1916 called collar) (Bild 13.3.1.2.2) (Bild 13.3.1.2.2) or a rebate joint (Bild 13.3.1.2.2). They must be designed in such a way that one or more seals can be used.
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Reinforced concrete jacking pipes must be calculated, designed and manufactured according EN 1916 [DINEN1916:2003]. Their dimensions in Condition I (assumption of a complete participation of the concrete in the tensile zone) is based on DIN V 1201 [DIN1201] and in Condition II (complete neglect of participation of the concrete in the tensile zone) is based on DIN 1045 [DIN1045:2001]. As already mentioned in Abschnitt 13.1, every manufacturer must … |
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Besides reinforced concrete jacking pipes for gravity pipelines, use is also made in trenchless installation of reinforced concrete pressure pipes. Reinforced concrete pressure pipes are reinforced concrete pipes with circular cross section 250 ≤ DN/ID ≤ 4000 (larger by agreement) for pipes that are subject to an overpressure or vacuum in operation and which are dimensioned and reinforced to suit the structural requirements in accordance with the … |
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Sep 24, 2007 Trenchless Technology for Installation of Cables and Pipelines Concrete and reinforced concrete jacking pipes with integrated corrosion protection (Image: Examples for jacking pipes made of various materials - Reinforced-concrete - vitrified clay [FI-Steinb]) Jacking pipes of reinforced concrete with vitrified clay combine the advantages of the corrosion protection of vitrified clay pipe to EN 295 [DINEN295d] with the high load bearing capacity of the reinforced concrete pipes. Through this an adaptation to the static and dynamic loading with simultaneous corrosion safety is possible. These … |
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