1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU L.38 (09/99) _- SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT Use of trenchless techniques for the construct ion of u nde rg rou nd i nf rastr uctu res for
2、telecommunication cable installation i ITU-T Recommendation L.38 (Previously CCITT Recommendation) ITU-T L-SERIES RECOMMENDATIONS CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT IlIII For further details, please refer to ITU-T List of Recommendations. - STDaIT
3、U-T RECMN L.38-ENGL L999 4862571, Obb5L35 5T2 ITU-T RECOMMENDATION L.38 USE OF TRENCHLESS TECHNIQUES FOR THE CONSTRUCTION OF UNDERGROUND INFRASTRUCTURES FOR TELECOMMUNICATION CABLE INSTALLATION Summary This Recommendation describes the main techniques which allow installation of underground telecomm
4、unication network infrastructures minimizing or eliminating the need for excavation. These techniques, commonly known as trenchless or no-dig techniques, create a horizontal bore below the ground in which the underground infrastructure (ducts, pipes or direct buried cables) can be placed. Trenchless
5、 techniques can reduce environmental damage and social costs and at the same time, provide an economic alternative to open-trench methods of installation. After a description of the available techniques, this Recommendation examines the different kinds of work that are performed, the preliminary ope
6、ration that shall be carried out, the drilling operation and the installation procedure advising on general requirements. Source ITU-T Recommendation L.38 was prepared by ITU-T Study Group 6 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 24th of September 1999. Recomme
7、ndation L.38 (09/99) I FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operatin
8、g and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their tur
9、n, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative ba
10、sis with IS0 and IEC. NOTE In this Recommendation the term recognized operating agency (ROA) includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms Administration, ROA and public correspondence are defined in the Constituti
11、on of the ITU (Geneva, 1992). INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability
12、of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement
13、this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1999 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, elec
14、tronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. ii Recommendation L.38 (09/99) _ STDmITU-T RECMN L-38-ENGL 1999 H 486259% 0bb5337 375 CONTENTS Page 1 2 3 3.1 3.2 3.3 4 5 5.1 5.2 6 6.1 6.2 6.3 6.4 7 8 8.1 8.2 8.3 8.4 9 9.1 9.2 9.3 9.4 Scope Avai
15、lable techniques Kinds of work . Long sections Crossings Urban environment . Site investigation Preparatory steps Use of trenchless techniques not requiring the excavation of a launch pit Use of trenchless techniques that require the excavation of a launch pit . 5.2.1 Impact moling . 5.2.2 Pipe ramm
16、ing 5.2.3 Microtunnelling and pipejacking Drilling operations Guided boring/directional drilling 6.1.1 Pilot bore creation . 6.1.2 Reaming and pullback . 6.1.3 Duct inspection . Impact moling . Pipe ramming . Pipejacking and microtunnelling Record keeping and documentation . Ground conditions Guided
17、 boring/directional drilling Impact moling . Pipe ramming . Pipejacking and microtunnelling Applications . Guided boring/directional drilling Impact moling . Pipe ramming . Pipejacking and microtunnelling Recommendation L.38 (09/99) 1 1 2 5 9 9 9 10 10 11 12 12 13 13 13 . 111 STD-ITU-T RECMN L.3B-EN
18、GL It999 H 4862593 Obb5338 20s 10 Conclusion 11 Glossary Appendix I - Available techniques Guided boring and directional drilling . 1.1.1 Methods . I . 1.2 Drilling machines I . 1.3 Drill pipes I . 1.4 Drilling fluids I . 1.5 Tracking and guidance systems . I . 1.6 Ancillary equipment 1.2.1 Monitori
19、ng I . 1 1.2 Impact moling . 1.2.2 Head types . 1.3 Pipe ramming . 1.3.1 Set-up 1.3.2 Bore options 1.4 Pipejacking and microtunnelling 1.4.1 1.4.2 1.4.3 1.4.4 1.4.5 1.4.6 1.4.7 1.4.8 1.4.9 1.4.10 1.4.1 1 1.4.12 Planning Excavation and spoil removal in pipejacking . Excavation and spoil removal in mi
20、crotunnelling Microtunnelling work method classification Position detecting methods . Soil improvement methods . Jacking frames . Shafts . Pipes Lubrication Interj acks . Jacking loads . Page 13 14 14 14 15 16 18 18 19 20 20 21 22 22 22 23 23 24 25 25 29 30 31 32 32 32 33 34 34 iv Recommendation L.3
21、8 (09199) Recommendation L.38 Guided boring/directional drilling USE OF TRENCHLESS TECHNIQUES FOR THE CONSTRUCTION OF UNDERGROUND INFRASTRUCTURES FOR TELECOMMUNICATION CABLE INSTALLATION (Geneva, 1999) Fluid-assisted boring Dry boring 1 Scope This Recommendation: e makes a classification of differen
22、t kind of works that are performed; describes the drilling operation and installation procedures requirements; describes situations where trenchless techniques are recommended. e describes the preliminary operations; e Microtunnelling 2 Available techniques A broad classification of the available tr
23、enchless techniques is given in Table 1. A more detailed description of each technique is reported in Appendix I. High strength pipe method * Penetrating method * Auger excavation method * Slurry method * Slurry pressure balanced method * Boring method * Auger excavation method * Slurry method * Slu
24、rry pressure balanced method * Boring method Low strength pipe method * Penetrating method I Piperamming 3 Kinds of work The following work classification is performed in order to give advice on the best equipment to use, depending on the different operational needs. 3.1 Long sections Trenchless tec
25、hniques can be used to install underground ducts along the roads as an alternative to traditional digging techniques. Long installation lengths can be achieved (several km) by dividing the work length into shorter sections (100-200 m as an average). The length of each section will depend on the char
26、acteristics of the machines and the design requirements. Recommendation L.38 (09/99) 1 It is recommended: that guided boringdirectional drilling (both fluid-assisted and dry boring) machines be used for this particular application. 3.2 Crossings River and railway crossings were the first application
27、s of no-dig technology due to the fact that traditional digging techniques were not suitable. Surface-launched machines are often the best solution because obstacles can be crossed with a curved drilling path, thus avoiding the need to excavate deep launch and reception pits (especially in river cro
28、ssings). It is possible to consider two different kinds of crossing with respect to the length and to the depth of the installed duct. - Road and railway crossings: the length of the drilling is normally not very long. For these situations it is recommended that both fluid-assisted and dry direction
29、al drilling machines be used or the use of microtunnelling systems depending on the duct diameter. River crossings: the length and the depth of the bore normally required are very long and deep and it is important to avoid the excavation of big launch and reception pits on the opposite sides of the
30、river. For these situations: it is recommended that the drilling is started directly from the surface using a fluid-assisted directional drilling system. - 3.3 Urban environment This represents one of the most attractive applications of no-dig technology because it could avoid or drastically reduce
31、the troublesome drawbacks normally created by digging work in urban areas. Due to the small diameters of the ducts and the short distance of each drilling section (manholes or chambers are normally very close together), it is recommended that a small and dry directional rig is used, in order to redu
32、ce the overall dimension of the working site, and to avoid flooding of the drilling fluid along the drilling path and the use of microtunnelling systems, depending on the duct diameter. 4 Site investigation Exhaustive knowledge of the work site and of the subsoil, right from the first design phases
33、is essential, both to reduce the number of failures and/or to limit possible damage to pre-existing services or structures and to minimize horizontal digging costs by use of the various no-dig techniques. It is therefore recommended that: The drilling plan shall be accompanied by a series of informa
34、tion of the following kind: - statutory/administrative; - - geolithological, hydrogeological and geotechnical. technological (e.g. presence of utilities or obstacles); Most of this information can be acquired by consulting pre-existing documentation of work carried out in the area (e.g. laying of ut
35、ilities, etc.). 2 Recommendation L.38 (09/99) e Maximum care shall be paid to public utilities which are potentially dangerous (e.g. gas mains) or of public importance (e.g. hospital telephone lines). Further essential information on important or potentially dangerous circumstances may sometimes be
36、obtained from the contracting company which executed the work. The following information on the services or structures is also necessary: - materials (PVC, metal); - diameter, single or multiple; - - infll materials (rubble, sand). planned and/or real depth of emplacement; It is sometimes necessary,
37、 when working with documentation made available by local authorities or other companies, to distinguish between “planning“ and “as installed“ drawings. Due to these reasons, in order to get precise information on the location of existing buried utilities, it is recommended that: a direct on-site inv
38、estigation should definitely be performed using appropriate equipment. Pipe and cable locators can detect metallic pipes, current carrying electrical cables and telecommunications cables. Ground Penetrating Radar systems give greater information often detecting non-metallic pipes, cables, zones of l
39、eakage and sub-surface discontinuities such as road construction layers or rock strata. Complete information about soil conditions can be obtained by conventional trial-holes and borings. 5 Preparatory steps 5.1 For trenchless techniques not requiring the excavation of launch and reception pits, it
40、is recommended that: Use of trenchless techniques not requiring the excavation of a launch pit before starting the work it is necessary to make an accurate evaluation of the available space when drilling fluids are used, the overall dimension of the truck carrying the pump and the when positioning t
41、he machine, it is necessary to consider the angle of incidence of the first if drilling fluids are used it is necessary to dig a small pit around the starting point to recover in order to be able to monitor the pilot-bore position from the surface during the drilling close to the starting point, tak
42、ing into account the dimension of the equipment to be used; tanks which are connected to the drilling machine shall be taken into account; rod with respect to the ground. This angle should not exceed 20“ and consequently the drilling machine has to be placed at a suitable distance far from the start
43、ing point; the mud produced by the drilling operations; operations, the drilling head should be equipped with sensors for measuring the following parameters: - depth; - inclination; - orientation; - temperature. e e e Recommendation L.38 (09199) 3 when using the walk-over system (see Appendix I), it
44、 is necessary to calibrate the gain of the receiver, according to the manufacturers instructions, before starting the drilling of the pilot bore; it is also advisable to mark the drill pipes in line with a definite position of the drilling head (e.g. with the angled face up). This will enable the op
45、erator to judge the actual orientation of the drilling head during the boring of the pilot hole, 5.2 Use of trenchless techniques that require the excavation of a launch pit 5.2.1 Impact moling When using the impact moling technique, once the desired route has been established, and before starting t
46、he creation of the bore, the following operations are recommended o a launch pit and a reception pit are first excavated at the ends of the bore path, that are a the launch cradle, if used, is then set up; alternatively the mole can be positioned directly on using a ranging rod in the reception pit
47、and a sighting telescope in the launch pit, the initial little deeper than the planned depth of installation; the floor of the launch pit; line of the bore is established by physically aiming the mole towards the ranging rod target; the mole is launched and allowed to advance a short distance. The l
48、ine is checked for a final time before the whole body of the mole enters the ground. If the line is not correct, the bore is restarted. 0 5.2.2 Pipe ramming When pipe ramming systems are used, the following preliminary operations are recommended o a typical ramming operation requires the establishme
49、nt of a solid base, normally a concrete mat, on the launch side of the installation. This mat will usually be positioned in a starting pit or alternatively against the side of a slope; o guide rails set to the line of the bore should then be installed on the mat; after positioning the first length of steel pipe on the guide rails, a cutting edge has to be depending on the diameter, inserts may have to be used to ensure solid and uniform contact o formed or fitted to the lead end of the pipe, and the ramming hammer is attached to the rear of the pipe; between the hamm
