1、105 Decker Court, Suite 825, Irving, TX 75062 P: 469-499-1044 F: 469-499-1063 www.plasticpipe.org Copyright, The Plastics Pipe Institute, Inc. 2009 Guidelines for Use of Mini-Horizontal Directional Drilling for Placement of High Density Polyethylene Pipe TR-46 2009 Prepared by: Dr. Larry Slavin Memb
2、er of the HDPE Municipal Advisory Board Outside Plant Consulting Services, Inc. (OPCS) 15 Lenape Avenue, Rockaway, NJ 07866-1019 for The Plastics Pipe Institute 105 Decker Court, Suite 825, Irving, TX 75062 P: 469-499-1044 F: 469-499-1063 www.plasticpipe.org Copyright, The Plastics Pipe Institute, I
3、nc. 2009 FOREWORD Guidelines for Use of Mini-Horizontal Directional Drilling for Placement of High Density Polyethylene Pipe This report was developed and published with the technical help of the members of the PPI (Plastics Pipe Institute, Inc.). The members have shown their interest in quality pro
4、ducts by assisting independent standards-making and user organizations in the development of standards, and also by developing reports on an industry-wide basis to help engineers, code officials, specifying groups, and users. The purpose of this technical report is to provide important information a
5、vailable to PPI on a particular aspect of polyethylene pipe butt fusion to engineers, users, contractors, code officials, and other interested parties. More detailed information on its purpose and use is provided in the document itself. This report has been prepared by PPI as a service of the indust
6、ry. The information in this report is offered in good faith and believed to be accurate at the time of its preparation, but is offered without any warranty, expressed or implied, including WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Consult the manufacturer for more detailed
7、information about the particular joining procedures to be used with its piping products. Any reference to or testing of a particular proprietary product should not be construed as an endorsement by PPI, which does not endorse the proprietary products or processes of any manufacturer. The information
8、 in this report is offered for consideration by industry members in fulfilling their own compliance responsibilities. PPI assumes no responsibility for compliance with applicable laws and regulations. PPI intends to revise this report from time to time, in response to comments and suggestions from u
9、sers of the report. Please send suggestions of improvements to the address below. Information on other publications can be obtained by contacting PPI directly or visiting the web site. The Plastics Pipe Institute, Inc. http:/www.plasticpipe.org This Technical Report, TR-46, was first issued in Decem
10、ber 2009. Guidelines for Use of Mini-Horizontal Directional Drilling for Placement of High Density Polyethylene Pipe Table of Contents 1. Scope . 52. Referenced Standards and Specifications . 63. Terminology 64. Preliminary Site Investigation . 114.1 General Considerations 114.2 Existing Belowground
11、 Utilities 124.3 Surface Investigation 124.4 Subsurface Investigation . 134.5 Non-HDD Situations 155. Safety and Environmental Considerations 165.1 General Considerations 165.2 Safety Training . 165.3 Work Clothing 175.4 Machine Safety . 175.5 Electrical Strike 185.6 Natural Gas Line Strike 195.7 Da
12、mage to Existing Utilities 195.8 Environmental 195.9 Proficiency 206. Regulations and Damage Prevention 216.1 General Considerations 216.2 Locating and Marking 226.3 Tolerance Zone . 236.4 Subsurface Utility Engineering . 247. Pipe Design and Selection Considerations 247.1 Objectives . 257.2 Minimum
13、 Wall Thickness Based upon Depth 267.3 Minimum Wall Thickness Based upon Pulling Load . 277.4 Results 317.5 Comments . 328. Bore Path Planning and Drill Rig Setup . 328.1 General Considerations 338.2 Steering see Figure 3. 3.3.1 The “Radius of Curvature”, or “Bend Radius”, is the distance from the c
14、enter of the circular path or configuration, in a plane, to the perimeter. 3.3.2 The “90 Bend Radius is the distance along a 90 portion (quadrant) of the perimeter of the circular path. 3.3.3 The “Degrees per Rod” is the angular change along a single rod length. 3.3.4 The various measures for quanti
15、fying the allowable curvature are related by the following formulae: 90 Bend Radius (ft) = 90 x Rod Length (ft) / Angular Change (deg/rod) (1a) Radius of Curvature (ft) = 90 Bend Radius (ft) / 1.57 (1b) Radius of Curvature (ft) = 57.3 x Rod Length (ft) / Angular Change (deg/rod) (1c) - 10 - Figure 3
16、 Rod or Pipe Curvature Terminology (Source: Outside Plant Consulting Services, Inc.) Figure 4 illustrates the above relationships. See Appendix A for examples quantifying the bending capability of typical drilling rods, using the various terms. There is significant quantitative difference between th
17、e 90 Bend Radius and Radius of Curvature. The latter (Radius of Curvature) is approximately 2/3of the 90 Bend Radius. For convenience, except where otherwise indicated, the Radius of Curvature (Bend Radius) measure will be used in the present document. - 11 - Figure 4 Allowable Curvature Relationshi
18、ps (Source: Outside Plant Consulting Services, Inc.) 4. Preliminary Site Investigation Section 4 describes the background information that would assist the contractor or engineer in planning the project, in order to help ensure an efficient, successful installation during the later construction phas
19、e. This investigation includes an evaluation of surface and subsurface conditions to determine the compatibility of the site with the proposed directional drilling operation. Of particular importance is the need to understand the presence and nature of existing belowground utilities, as discussed in
20、 Section 4.2 in order to avoid damage to such lines. 4.1 General Considerations 4.1.1 Unlike maxi-HDD installations, typical mini-HDD projects may be brief undertakings, requiring as little as a single day, such as for a road crossing, or less for a service line, to extended periods of many months o
21、r more for a large scale upgrade of degraded utility distribution lines serving an entire community. The feasibility and desirability of using mini-HDD for a particular project, as opposed to a larger machine (e.g., midi-HDD), or open-cut trenching, depends upon many factors, including soil conditio
22、ns, location of other utilities, environmental aspects, and particular features and characteristics of the existing area. The size and anticipated duration of the project is an important consideration with respect to the amount of preliminary planning and investigations that may be practical. - 12 -
23、 4.1.2 For relatively extensive projects, such as for upgrading utility lines across a community, the owner of the facility to be placed or his representative (e.g., a geotechnical engineer), or the (potential) contractor, should perform a preliminary site investigation well in advance of the constr
24、uction. Ideally, the owner would conduct as much of the preliminary investigation as possible to allow a meaningful and equitable bidding process. The contractors would conduct additional investigations to assist them in the bidding process, as well as to provide guidance for the actual construction
25、, following awarding of contracts. For projects of very limited duration, the contractor may perform only a brief study, to verify the general feasibility and determine the equipment and resources required to successfully complete the task. 4.1.3 The presence of special obstacles or situations must
26、be considered. For example, the presence of pollutants or contaminants in the construction area must be identified, including corresponding arrangements for spoil disposal. 4.2 Existing Belowground Utilities 4.2.1 Mini-HDD technology was primarily developed as means of installing new utility lines i
27、n developed areas, including residential applications, and at various crossings of limited extent, with minimal surface damage. However, in order to avoid damage to belowground facilities, public or private, as well as to judge the magnitude of the effort, it is essential to understand the nature of
28、 such lines and structures, including types and likely locations and depths. Information obtained at the preliminary stage will help guide the subsequent more detailed inspections and locations required immediately prior to, and during, the actual construction stage. 4.2.2 The new distribution lines
29、 will generally be placed along the main right-of-way (ROW), and associated service lines will typically be installed laterally beneath the individual properties. Since minimum specified clearances must be maintained from existing lines in the ROW, the available remaining space within the ROW should
30、 be verified, as a measure of the potential difficulty of the installation. New distribution cables will routinely be crossing existing service lines for individual buildings, residences or structures, which will be exposed during the construction stage (Section 6.2.3). In addition to the utility se
31、rvice lines, the presence and frequency of privately installed electric or lawn sprinkler lines within the community should be considered. 4.2.3 Important regulations and damage prevention procedures are discussed in Section 6. 4.3 Surface Investigation 4.3.1 The surface area of immediate interest c
32、orresponds to that specified or desired by the owner of the new facility, consistent with the utility network architecture, including the number and size of pipes required, and their termination points. - 13 - 4.3.2 The contractor should review the construction site to verify there is sufficient roo
33、m for the drill rig and auxiliary equipment, vehicles, trailers, at both ends of the bore. The drill rig working areas should be reasonably firm, level, and suitable for the movement of rubber tires or treads. For PE pipe of relatively large diameter, not provided on a reel, for which pipe prefabric
34、ation is necessary, appropriate space must be provided for the fusion equipment, as well as an area for temporarily placing the assembled pipe. The presence of possible interfering aboveground structures or overhead power or telephone lines should be considered with regard to equipment movement. 4.3
35、.3 The ability for the tracking and monitoring system to function properly may be hampered by the local conditions, along the path to be bored. Conventional walkover receivers require direct overhead access, while more sophistical systems may allow remote tracking. Potential sources of interference
36、to the electronic locators of mini-HDD tracking systems include overhead structures or wire lines, as well as steel-reinforced concrete sidewalks, driveways, and roads. 4.3.3 The use of drilling fluids requires that a source of water, preferably potable, be available for mixing. Although drilling fl
37、uids are not considered hazardous materials, excess fluid and associated spoils must be disposed of properly. The location of an appropriate disposal area, consistent with local regulations, should be identified in advance of the construction, as part of the preliminary or planning phase. 4.3.4 Alth
38、ough noise levels associated with mini-HDD equipment are generally not excessive, there may be restrictions on work hours in areas near residential buildings, hospitals, or other institutions. 4.4 Subsurface Investigation 4.4.1 The effectiveness and efficiency of most belowground construction operat
39、ion is dependent upon the soil conditions, and is especially relevant for HDD technology. Directional drilling installations must simultaneously penetrate and maneuver through the soil, using less aggressive techniques than conventional open-cut trenching. Problematic soil conditions can slow progre
40、ss and/or lead to damage to public and private property and safety hazards. It is therefore important to perform an investigation of the local soil characteristics and ground conditions, including potential obstacles, to verify the feasibility of employing mini-HDD for the proposed project, as well
41、as to result in more realistic cost estimates and avoid inequities to the owner or contractor. In order to be cost-effective, however, the extent of the subsurface investigation, should be compatible with the magnitude of the overall project. 4.4.2 The soil investigation should attempt to evaluate c
42、onditions at the nominal placement depth of the product pipe. Mini-HDD technology is capable of placing utility lines or pipes as deep as 15 ft. In many cases, however, the desired or required depth for utility distribution lines will be relatively shallow - possibly within six feet of the surface.
43、(Greater depths may complicate subsequent repair and maintenance procedures.) Such mini-HDD installations will also likely be in established areas, including residential communities. Thus, the relevant belowground conditions are not necessarily that of virgin soil at greater - 14 - depths, but that
44、of disturbed or filled areas, possibly including various debris or obstacles resulting from prior construction activities. 4.4.3 For relatively large scale projects, the investigation may include a review of published reports from various government agencies (e.g., state or county soil conservation
45、service reports, U. S. Geographic Survey, U. S. Army Corps of Engineers reports). However, in recognition of the possible lack of correlation of such virgin soil studies relative to the possibly disturbed conditions, at shallow depths, as described above, records from previous local construction pro
46、jects, of large or small extent, would be of particular value, if available from other utilities or owners. The latter information may also reveal the presence of belowground structures, including those that may have been abandoned. Construction information and experiences from previous local projec
47、ts involving trenchless methods, requiring boring of any type, would be most relevant. 4.4.4 Soil Investigation Tests If warranted by the scope of the project, existing subsurface information may be supplemented by local soil tests, at strategic locations and relevant depths, to verify the condition
48、s. Possible characteristics to be evaluated include standard classification of soils, standard penetration test values, rock type and strength and (Mohs) hardness.(ASCE 108) ASTM F 1962 provides reference ASTM test methods for soil evaluation studies, as appropriate. More extensive information is av
49、ailable elsewhere.(3) 4.4.5 For some mini-HDD applications, such as large scale upgrades of distribution facilities in established areas, random blockages due to man-made debris would not be evident based upon soil testing at a limited number of locations. Depending upon the depths of interest, object dimensions, and soil conditions, existing technology (e.g., ground penetrating radar) may be capable of electronically scanning the subsurface to detect obstacles of various sizes. Such technologies are continuing to evolve and their practicality,
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