11094 search results:

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Vertical and horizontal deviations

The principle of measurement is based on the physical property of fluids in connected containers of any cross section always to find the same level (communicating pipes).

In practice, electronic levelling units are used exclusively in measurements in most trenchless installations.

During the whole of the jacking course, the electronic levelling unit determines the MSL height of the machine.

(Image: Functional principle of a hose water level)

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Vertical and horizontal deviations

(Image: Hose of the hose water level (green) within the pipe string)
(Image: Determination of position and direction)
(Image: Position determination - Reference module of the hose level (height level always above the level of the tunnelling machine))

The electronic levelling unit consists of three modules [FI-Bodenb]:

  • The hose line which is led through the whole of the pipe string and which connects the height sensor in the machine with the reference …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Inclination and rolling

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 …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Inclination and rolling

Mechanical pendulums can be used for jacking methods with an illuminated target board and picture transmission by a video camera. The required angle is read off using the monitor; an electrical signal that can be evaluated for automatic steering is not received.

(Image: Mechanical pendulum for measuring changes in the angle of inclination [Stein87g])

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Jacking progress

The measurement of the distance travelled by the jacking or shield machine or by the boring and displacement head (jacking advance) is of primary importance for determining position. This can be carried out by means of:

  • Addition of the lengths of installed pipe segments or pilot bore string

  • Measurement and addition of the path length of the jacking cylinder of the jacking station or the main jacking station plus intermediate jacking stations

  • Electronic …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Jacking progress


In microtunnelling and pipe jacking, the electronic measuring wheel is used most often as a simple and reliable method of measurement. It is fixed at the gasketed opening and rests on the crown of the passing pipe string. The rotation of the wheel generates electrical impulses that are evaluated by the central computer for determining the length of the pipe string that has passed under it.

(Video: Electronic measuring wheel)

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Jacking progress

For electronic distance measurement, also called EDM, the distance is derived from the time taken by the speed of propagation, with constant velocity, of a signal. A transmitter set up at the starting point of the drive, sends the signal to a reflector that returns it to the starting point. In trenchless installation, the electro-optical distance measurement with laser light as the signal carrier has been successful.

With electronic distance measurement …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

To determine the position in trenchless technology measurement systems with different combinations of measuring techniques are applied with reference to process engineering and especially the line path and accessibility of the pipe string (nominal pipe size).

Straight jacking projects

Measurement from the starting shaft

(Image: Non-steerable techniques)

Curved jacking projects

Measurement inside the pipe string (without intervisibility to the starting …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Table: Overview of measurement systems used in trenchless installation)

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems


With reference to the method of measurement from the starting shaft (with line of sight) one differentiates between:

  • Theodolite or laser theodolite with direct target board observation
  • Theodolite or laser theodolite with video observation of the target board
  • Laser with active target board
(Image: Attention!)

In order to carry out this measurement technology, there must be a line of sight over the whole jacking distance, which means a free …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Image: Non-steerable techniques)
(Image: Illuminated passive target board fixed at the cutting shoe of a shield machine with mechanical partial excavation [FI-Gewer])
(Image: Observing the passive target board with a theodolite [Stein87g])

With this measurement system a passively illuminated or self-illuminated target board (diode target board) is observed by the person carrying out the measurement or the equipment driver at predetermined …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Image: Non-steerable techniques)

This measurement system corresponds in principle to the one with theodolite or laser theodolite with direct target board observation. In this case, the picture of the target board is not seen directly by an observer but is recorded by a video camera that can be installed either in the target board itself, near the target board or in the ocular of the theodolite and is transmitted as a monitor display to the control …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Image: Non-steerable techniques)

The combination of directional laser with active target board has found wide acceptance especially with microtunnelling and pipe jacking for a selection of manual, semi- or fully automatic steering methods [Fitzk94]. In this case, a laser beam that impinges on an active target board is used as an optical means of guidance.

One representative of this standard measurement system is the ELS (Electronic Laser System) […

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

The ELS consists of the following components:

  • Directional laser

  • Active target board with built-in dual-axial inclinometer

  • Computer with monitor, printer and data cable

  • Measuring wheel

(Image: Steering components of a microtunnelling machine - Detail views of the monitor display for a microtunnelling machine type AVN 1200 [FI-Herreb]) (Image: Steering components of a microtunnelling machine - Steering desk [FI-Herreb]) (Image: Steering components …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

For pipe jacking in which the measurements can no longer originate from the starting shaft because either the distance between the target-beam generating instrument in the starting shaft and the target board in the shield machine is too great or the line of sight between the two modules is interrupted due to curves or curvature, the measurement in the pipe string is carried out using the following variants:

  • Measurement with static device

  • Measurement …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Image: Steerable techniques)

Static measurement with a theodolite is the oldest measurement method used in pipe jacking [Borne83] [Jacob96]. In order to acquire the position of the shield machine, it is necessary with each measurement procedure to measure and calculate the whole survey traverse and altitude transfer from the starting shaft up to the target board.
(Image: Attention!)

Jacking must be stopped for the period of the measurement …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

In order to eliminate the disadvantage of static measurements, increasing use is being made of measurements with measurement instruments accompanying the pipe string (dynamic survey transverse measurement). These measurement systems include:

  • Survey transverse measurement with onboard servo Total Station

  • Onboard gyroscope with directional laser

  • Automatic survey transverse measurement (measurement with the aid of onboard measurement station

(Image: …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Image: Steerable techniques)

Representatives of the survey traverse measurement with onboard Servo Total Station include:

  • ZED-206P [FI-ZED]
  • SLS-RV [FI-VMT].
(Image: SLS-RV control system [FI-VMT] - Active target board)
(Image: SLS-RV control system [FI-VMT] - Servo Total Station with automatic levelling plate on the console)

The SLS-RV consists of the following individual components:

  • an active target board as a fixed installed positional …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Video: Steering control system pipe jacking SLS-RV)

Video: Steering control system pipe jacking SLS-RV with reference to [FI-VMT] [Image: S&P GmbH]. This interactive object is only visible online.

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Image: Steerable techniques)

In place of an onboard Servo Total Station as well as the connection to survey prisms for survey traverse measurement, use can also be made of a gyroscope in connection with a directional laser.

A representative of the measuring system "onboard gyroscope with directional laser" is the NELS curve measurement system [FI-Herreb]. It consists of:

  • A North seeking module, e.g. a gyroscope with two inclinometers

  • A directional …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

For elevation determination, this measuring system NELS uses the theory of the invariance of the traversed cavity. The 3-D coordinates of the gyroscope which are constantly calculated with regard to position and altitude from a known reference track help in obtaining the required altitude information so that a coupling to the starting shaft, whether during intermittent levelling or use of a hose level unit is not necessary.

 (Image: System overview …

Sep 09, 2008

Modules

Utility Tunnelling - Jacking steering, measurement and monitoring

Measuring systems

(Image: Steerable techniques) 

This automatic survey traverse measurement is a measurement whose quality is dependent, among others, on the accuracy of the direction transfer in the starting shaft, the accuracy of the measurements in the pipe string and the refraction influences.

A representative of the automatic survey traverse with onboard measurement station is, for instance, the (APM) automatic survey traverse system [FI-Hocht]. The measurement …

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