|
|
Jul 15, 2013 Depending on the construction task, various kinds of additional equipment are available to simplify and monitor the pulling-in process in practice, such as
|
|
|
Jul 15, 2013 In multiple installations, i.e. “the shared installation of several lines [...], which may also be of different types, in the same line and gradient“ [HDD-1], until today exclusively unbundled installation and bundled installation have been used (cf. Volume 1, Section 2.2 [HDD-1]). Due to the development of the multiple clamp for HDD, now group installation is also possible with this technology. Here single product and casing pipes are arranged as … |
|
|
Sep 25, 2013 (Image: Jacking station of the type "Pipe-Thruster HK 250/500PT" – Functional principle of tandem)When installing steel pipes of a large nominal size (> DN/ID 700) and for large borehole lengths a jacking station can systematically be employed at the pipe exit point in order to support the drill rig during pulling-in. A corresponding example is the “Pipe Thruster HK250/500PT“ (Figure 65 a) by the manufacturer Herrenknecht AG [HDD-174]. The “Pipe Thruster“ … |
|
|
Jul 15, 2013 (Image: Tensile load measuring system GRUNDOLOG III – View)According to DVGW-GW 321 [HDD-15], in Germany for plastic pipelines (e.g. of PE, see (PE-pipes)) basically the pullback between the reamer and the pulling head, which is connected with the pipeline, are to be measured and recorded for tracing the pulling-in process and to prevent the pipeline from possible overload [HDD-51]. In practice, this requirement to quality assurance has already been … |
|
|
Jul 15, 2013 Depending on the construction task, various kinds of additional equipment are available to simplify and monitor the pulling-in process in practice, such as
|
|
|
Jul 15, 2013 The requirements of space for the drill rig, the approach and the equipment of the site arrangement are strongly influenced by the size of the drilling rig, the type and the external diameter of the pipe(s) to be installed, the drilling distance and the selected pulling-in variant (see (Method of operation and sequence)) [HDD-55]. Generally, a difference must be made between the site arrangement at the entry point (starting pit) or starting shaft … |
|
|
Jul 10, 2013 |
|
|
Jul 15, 2013 In general, HDD can be used for borehole diameters of up 2200 mm (≈ 86 in.) (max. nominal pipe size PE: DN/OD 1400 (1500), steel: DN/OD 820, cast: DN/OD 842 [HDD-5]) with pipe lengths up to 3,000 m in soils and rock with and without groundwater [HDD-57]. These limiting values regarding nominal size and drilling distance, however, cannot be achieved simultaneously (i.e. a very long drilling run requires a substantially smaller borehole diameter and … |
|
|
Jul 15, 2013 Because of the variety in drilling tools, the application of these tools, the methods and parameters of drilling, the characteristics of drilling fluid and fluid pressures and their possible combinations, HDD has a wide area of application in soils and rock. According to [HDD-61], they are basically suitable for application in organic (Class LO) as well as in cohesive and noncohesive soils of Classes LB and LN according to DIN 18319 [HDD-62] or in … |
|
|
Jul 15, 2013 (Image: Difficulty levels when using HDD in rock – case examples for different subsoil conditions)Today in practice, drilling in rock of classes FZ 1/FD 1 to FZ 4/FD 4 (see DIN 18319 [HDD-62]) is possible with drill rigs with a pullback of ≥ 100 kN and by using roller cutting heads driven inside the borehole for pilot boring or hole openers (see (Drilling tools)) for reaming(s). Concerning the technical aspect of drilling, there are no limitations … |
|
|
Jul 15, 2013 In general, HDD can be used for borehole diameters of up 2200 mm (≈ 86 in.) (max. nominal pipe size PE: DN/OD 1400 (1500), steel: DN/OD 820, cast: DN/OD 842 [HDD-5]) with pipe lengths up to 3,000 m in soils and rock with and without groundwater [HDD-57]. These limiting values regarding nominal size and drilling distance, however, cannot be achieved simultaneously (i.e. a very long drilling run requires a substantially smaller borehole diameter and … |
|
|
Jul 15, 2013 HDD used in trenchless installation is counted among the near-surface directional drilling methods. While drilling, its spatial path is controlled and, if necessary, directionally oriented or influenced by means of technical or technological measures for the purpose of corresponding to the planned drilling profile [HDD-67] [HDD-68]. This influencing not only includes the maintenance of the prescribed drilling profile, but also the correction of natural … |
|
|
Jul 15, 2013 The following components are used for both variants of the measuring system:
|
|
|
Jul 15, 2013 (Image: Structure of a transmitter using the example of the PDF (Precision Dual Frequency DataSonde) by the company Radiodetection)Electromagnetic Walk-Over methods, also called active Walk-Over methods, are used in about 90% to 95 % of all cases of HDD [HDD-69] [HDD-72]. They are used with Mini to Mega drill rigs. Depending on the power supply of the transmitter, it is differentiated between the following variants:
|
|
|
Sep 26, 2013 (Image: View and structure of the pneumatically driven pilot boring head (displacement head) with integrated permanent magnet as a transmitter)Magnetic or passive Walk-Over methods work with a permanent magnet as a transmitter (passive transmitter) inside the drill head (Figure 83) and are scarcely employed in practice. The receiver locates the magnetic field via four magnetometers inside a sensor plate (Figure 84 a). The magnetometers send this … |
|
|
Jul 15, 2013 The following components are used for both variants of the measuring system:
|
|
|
Jul 15, 2013 The Wire-Line method is a locating technique with cable (direct) based on the natural terrestrial magnetic field or, if required, based on an artificially generated magnetic field. It originates from deep drilling technology and is mainly used with large drill rigs and correspondingly long and deep drillings. The most important system components are:
Sensors … |
|
|
Jul 15, 2013 The following locating techniques, for example, belong to alternative locating techniques that are only employed in major drilling technology:
DWA-A 125 [HDD-10] recommends to employ a gyroscope or gyro compass or the parallel bore measuring method in hardly accessible or non-accessible areas with strong magnetic interferences. |
|
|
Jul 15, 2013 The gyroscope or gyro compass is used in connection with the Wire-Line method (see (Wire-Line method)) [HDD-84] [HDD-85]. It replaces the magnetometer in cases in which the terrestrial magnetic field is disturbed and the complicated creation of an artificial magnetic field by installing a cable loop is impossible (e.g. TruTracker®- System) or is not sufficient in the case of ferro-magnetic influence (e.g. tank, industrial and rail installations, … |
|
|
Jul 15, 2013 In the parallel bore measuring method an already created drill bore is used for steering and controlling the parallel, subsequent pilot bore(s) by employing corresponding measuring technology (soft- and hardware). This measuring and locating techniques is used if drillings have to be carried out in a parallel way and with relatively small clearance on the sides and /or in the limits of the minimally permissible elastic bending radius or permissible … |
|
|
Jul 15, 2013 In cases where it is no longer possible to locate the drill head by means of the Wire-Line method over long drilling sections due to topographical reasons (e.g. when crossing bodies of water, below buildings, etc.) or where enormous interferences are to be expected the measuring method of “positioning of a magnetic field transmitter in the area of the drill path“ can be applied from the very beginning or as a supporting measure. A representative system … |
|
|
Jul 15, 2013 The following locating techniques, for example, belong to alternative locating techniques that are only employed in major drilling technology:
DWA-A 125 [HDD-10] recommends to employ a gyroscope or gyro compass or the parallel bore measuring method in hardly accessible or non-accessible areas with strong magnetic interferences. |
|
|
Jul 15, 2013 HDD used in trenchless installation is counted among the near-surface directional drilling methods. While drilling, its spatial path is controlled and, if necessary, directionally oriented or influenced by means of technical or technological measures for the purpose of corresponding to the planned drilling profile [HDD-67] [HDD-68]. This influencing not only includes the maintenance of the prescribed drilling profile, but also the correction of natural … |
|
|
Jul 15, 2013 In carrying out drillings, difficulties in part are inherent to this type of work repeatedly occur and thus lead to enormous financial losses on the client’s as well as on the contractor’s side. These failed drillings also are frequently caused by insufficient construction preparations as well as insufficient geotechnical investigations or explorations by the client and the contractor. Such investigations are a critical part of the use of this method [… |
|
|
Jul 15, 2013 (Image: Influence of the subsoil on HDD)For using HDD methods, accurate and comprehensive information on the subsoil, based on qualified and targeted subsoil investigations carried out by the client, is a necessity in order to be able to ensure its feasibility and to reduce the subsoil risk to a minimum [HDD-17]. The building owner as the client is basically responsible for the subsoil and its associated characteristics. Also, in line construction, … |
11094 search results:
