Category: Pipe Ramming
This trenchless technology is used for the installation of steel pipes or casings under roads, railway lines and other structures using pneumatically driven pipe ramming machines. The casing is open ended to permit the excavated soil to pass through the casing as the pipeline construction advances. These machines enable the economic installation of the pipeline and/or product pipes up to 4000mm diameter over lengths up to 80m in class 1 - 5 soils and possibly some class 6 soils such as easily soluble rock, without the need for jacking abutments. Since the soil is contained, the threat of ground settlement is minimised so the technology can be used for the construction of shallow depth pipelines and in poor ground conditions such as running sand, sands & gravels etc.
The use of Pipe Ramming to install pipelines under roads and railways in particular is suitable for the provision of all types of utility service pipes or ducts.
This is a straightforward process and is suitable for installing longitudinally welded pipes, spirally welded pipes, seamless pipes and pipes with insulation protection and promotes a wide range of applications such as: -
• Installation of steel pipes underneath buildings, roads, water courses, railway tracks etc.
• Construction of pipe roofs for tunnel structures.
• Vertical applications e.g. for foundations, sheet piling or well drilling.
• Support of HDD bores (HDD Assist).
• Casing pipes for supply und drainage pipe bundles.
• Renewal of pipelines (dynamic pipe bursting).
The casing pipe is fitted with a cutting shoe and lubricant pipes and fitted to a stable rail system which allows the casing to be pushed into the soil embankment on the designed line and level. The pneumatically driven ramming machine is attached to the casing using a cone or collar system. The ram hammers the open ended casing pipe through the soil to the reception pit, with additional pipe lengths being welded onto the casing as the drive lengthens. Some soil may be removed during installation to reduce frictional drag of the casing however it is essential that enough soil is kept in the casing to maintain a plug at the cutting face until the completion of the drive, after which the soil contained within the casing is removed by high pressure water jetting, air-pressure or a combination of both and also by auger for larger casings for instance.
The ramming machine is driven by a conventional compressor. After being welded together, the single pipe strings are pushed forward gradually. Due to the robust one-piece construction, the largest ramming machine can achieve an impact energy of 40.000Nm at full capacity, which is transferred optimally over the complete pipe string to the pipe's front cutting edge. The average ramming speed is 10m/hour.
Advantages of the method:
• less disruption and damage to surfaces worth conserving and minimal restoration
• low social costs because detours, half-sided barriers etc. are avoided
• no jacking abutments or auger cutters required which could get jammed
• the soil core remains in the pipe during ramming, i.e. no ingress of water when rivers or high water table areas are encountered
• minimal depth of cover required, i.e. shallower excavations possible
• adaptable for all pipe diameters with special ram cones
• widely acknowledged and accepted simple technique
• short set-up and installation times
• wide application range
Last Updated on Wednesday, 13 August 2014 11:19