Quota item selection for trenchless horizontal directional drilling (directional drilling / pipe pulling): process split, diameter banding, measurement rules and multi-pipe single-bore diameter determination

Topic Positioning

This card explains quota item selection for trenchless directional drilling (colloquially pipe pulling; standard term "horizontal directional drilling") in municipal utility networks: how the processes are split into items, how diameters are banded, how quantities are measured, and how the bore diameter is determined when several pipes share one bore. The primary basis is Beijing's current DB11/T 2382-2024, with Shenzhen SJG 181.4-2024 and railway TB/T 10832-2024 attached for cross-reference.

Core Conclusions

1. Overall rule on process split and item selection. Horizontal directional drilling is not priced under a single all-in item: the three processes "pilot boring -> reaming -> pipe pull-back" are set as separate items and banded separately, all measured in metres. DB11/T 2382-2024 clause 7.4.58: "Horizontal directional drilling should, by pipe diameter, set items for pilot boring, reaming and pipe pull-back, with quantities computed as follows: 1 pilot boring and reaming by the horizontal length between the two working pits; 2 pipe pull-back by the pilot-bore length plus 1.5m."

2. Beijing 2024 item bands (Annex D municipal works, tables D.4.63-1 to 63-3, 15 items in total):

• Pilot boring: within 300 D4-11-152 / within 600 D4-11-153 / beyond 600 D4-11-154;
• Reaming: within 100 D4-11-155, within 200 D4-11-156, within 300 D4-11-157, within 500 D4-11-158, within 600 D4-11-159, within 800 D4-11-160;
• Pipe pull-back: within 100 D4-11-161, within 200 D4-11-162, within 300 D4-11-163, within 500 D4-11-164, within 600 D4-11-165, within 800 D4-11-166. There are no 400 or 700 bands; the largest band in the book is within 800 - beyond DN800 no band exists. Work content of the items: pilot boring "site preparation, installing the probe, connecting the drill string, pilot boring, on-site transport, clearing the site"; reaming "site preparation, installing the reamer, reaming, on-site transport, clearing the site"; pipe pull-back "site preparation, laying the pipe, pulling back, on-site transport, clearing the site". Reaming consumptions are listed with amortised multi-size reamers; multi-stage reaming is already included in the reaming items, with no separate items for each pass.

3. Diameter determination for several pipes in one bore. Shenzhen SJG 181.4-2024 clause 1.2.4 states expressly: "Where several pipes are actually laid in one bore, the bore, reaming and pull-back diameters shall be computed by the smallest circumscribed circle of the pipe bundle." In practice: compute the smallest circumscribed circle of the bundle arrangement, then band all three processes against that circumscribed diameter using the banding tables. Beijing's current standard has no equivalent multi-pipe clause; this determination is a cross-region reference - before review it should be confirmed with the cost management authority and recorded in the preparation notes.

4. Boundary-value convention. "Within / not greater than" includes the stated figure; "beyond / greater than" excludes it: SJG 181.4-2024 general provisions: "unless otherwise stated, 'xx within' or 'xx or less' in this standard includes xx itself, and 'xx beyond' or 'xx or more' excludes xx itself"; the basic provisions of DB11/T 2382-2024 state "where 'xxx beyond (or above)' is stated, xxx itself shall be excluded"; the Beijing highway and urban road supplementary quota general notes: "where 'within a figure' or 'a figure or less' is stated in the quota tables, the figure itself is included; where 'beyond a figure' or 'a figure or more' is stated, the figure itself is not included." Examples: DN300 takes the "within 300" band; DN320, with no 400 band, takes the "within 500" band directly.

5. Ancillary rules (Shenzhen SJG 181.4-2024 clause 1.1.5, cross-region reference):

• Pilot boring in soil is compiled across soil classes; rock covers soft rock and fairly soft rock - for fairly hard rock, the pilot-bore, reaming and pull-back items for soft and fairly soft rock apply with labour, material and machine-shift consumptions multiplied by 1.30; extremely soft rock takes the soil items;
• The pilot-boring items exclude setting-up, removal and backfilling of the slurry pit, the excavation and masonry of the entry and exit pits, and slurry treatment and haulage - where these occur they are computed separately per the design or the approved project execution plan;
• The reaming items already allow for multi-stage reaming from the bore diameter up to the pipe-laying requirement;
• The pull-back items cover metal and plastic pipes alike without distinguishing pipe material, but exclude pipe jointing and pipe prices, which follow the applicable pipe-installation items;
• The pipe-bursting diameter is the diameter of the new pipe; it applies to old pipes laid in soil, progressive and appropriately skipping expansions being included, the items selected by the material of the burst old pipe; bursting excludes jointing of and the price of the new pipe.

6. Version comparison. In Beijing's 2021 municipal consumption standard the like items ran from 11-152 (pilot boring within 300/600 and beyond 600) and 11-161 (pipe pull-back DN100 etc.); the 2024 edition restructures them into Annex D items D4-11-152 to D4-11-166. Beijing projects now follow the 2024 edition.

Applicability Boundaries

• The item numbers are specific to Beijing DB11/T 2382-2024; other provinces and cities apply their own consumption standards / quotas - the logic may be referenced but the numbers do not transfer; the smallest-circumscribed-circle rule for multi-pipe bores is express only in the Shenzhen standard, absent in Beijing - cross-region use must be recorded and confirmed with the cost management authority.
• This card addresses horizontal directional drilling (directional drilling / pipe pulling); pipe jacking (clause 7.4.56), micro auger jacking (7.4.57) and trenchless pipe rehabilitation (7.4.59: sliplining, CIPP inversion, FIPP thermoforming, UV curing etc., measured by design chainage with consumptions excluding pre-treatment) each have independent rules and must not be mixed.
• Beyond DN800 no band exists at present; a supplementary quota or a project-specific solution is required.
• Railway works refer to TB/T 10832-2024 Volume 11: PY-424 to PY-435 list pilot boring (DN not over 300/600), reaming (DN 100-600) and pipe pull-back (DN 100-600) separately, measured in 10m.

Further Reading

• DB11/T 2382-2024 "Consumption Standard for Construction Works", chapter 7 municipal works, 7.4 utility networks, section XI trenchless construction (7.4.56-7.4.60) and Annex D tables D.4.63-1 to D.4.63-3 (items D4-11-152 to D4-11-166);
• SJG 181.4-2024 "Consumption Standard for Municipal Works, Volume 4, Water Supply and Drainage Networks", clause 1.1.5 (ancillary rules) and clause 1.2.4 (multi-pipe single bore);
• TB/T 10832-2024 "Railway Works Budget Quota, Volume 11, Water Supply and Drainage Works", chapter 3 section 4 "Horizontal directional drilling" (PY-424 to PY-435);
• Beijing highway and urban road supplementary quota, general notes (the two-branch boundary-value wording, for reference).