Sonic logging pipe (cross-hole sonic test tube) quantities for bored piles: tubes per pile banded by diameter (JGJ 106-2014 / TB 10218-2019) and embedment length caliber (pre-driving natural ground to pile tip plus 0.5m, no extra overpour)

Topic Positioning

Two core questions in sonic logging pipe (cross-hole sonic test tube) quantities for bored piles: how many tubes per pile (testing-code requirements banded by diameter) and how embedment quantities are computed (length start/stop caliber, whether overpour adds, by length or mass). For measurement, pricing, and review under building, railway, and local systems.

Core Conclusions

1. Tubes per pile — banded by diameter; code values are floors JGJ 106-2014 "Technical code for testing of building foundation piles", 10.3.2: tubes are arranged symmetrically inside the cage and numbered. "Piles <= 800mm: not fewer than 2 tubes; > 800 and <= 1600mm: not fewer than 3; > 1600mm: not fewer than 4; > 2500mm: the number should be increased." Profiles: 2 tubes = AB; 3 tubes = AB, BC, CA; 4 tubes = AB, BC, CD, DA, AC, BD. This edition lowered the 3-tube upper bound from 2000mm to 1600mm. TB 10218-2019 "Rules for testing of railway foundation piles", 5.3.1 same: d <= 0.8m >= 2; 0.8 < d <= 1.6m >= 3; d > 1.6m >= 4; d > 2.5m increase. Metal tubes, ID >= 40mm, wall >= 3.0mm; bottom closed, top capped, no debris, smooth watertight joints; mouths >= 100mm above the concrete top and level; fixed inside the cage, parallel after concreting; numbered clockwise from the large-mileage apex. Testing: transducers raised/lowered in step, spacing <= 200mm and preferably >= 100mm. Stricter locals govern: Guangdong DBJ/T 15-60-2019, 12.3.2: d <= 800 >= 2; 800 < d <= 1600 >= 3; 1600 < d <= 2500 >= 4; d > 2500 >= 5; spacing <= 2500mm (preferably <= 2000mm); with >= 5 tubes, one near the pile axis (or a cored hole). Tianjin DB12/T 1122-2022, 8.3.1 (bridge piles): d < 1000 >= 2; 1000 <= d <= 1600 >= 3 equilateral; 1600 < d < 2500 >= 4 square; d >= 2500 increase; tube ID >= transducer OD + 15mm, wall preferably >= 2mm; mouths >= 100mm above the top.

2. Length caliber — from pre-driving natural ground, plus 0.5m, no overpour addition Norm rules:

• Railway TB/T 10831-2024 Vol. 10: "grout pipes and sonic tubes are measured from the natural ground level before driving to the design pile tip level plus 0.50m, times the mass per meter, in t."
• Railway TB/T 10823-2024 Vol. 2: tube quantities "by design steel-pipe mass, excluding embedded plates and other fixings" (with the tube fabrication items).
• Hunan 2025: "grout/sonic pipe embedment from pre-driving natural ground to design pile tip plus 0.5m, by length."
• Shenzhen SJG 111.1-2022, 3.2.2: "from pre-driving natural ground to design pile tip plus 0.5m, in tons; the item already covers casing and cap masses."
• Beijing DB11/T 2382-2024 Table A.3.2 "sonic pipe embedment" (A-3-16), unit m, welded pipe DN50 1.06 m/m. Caliber conclusion: length runs from pre-driving natural ground to design tip + 0.50m. Overpour and empty-hole above the design top are inside this start/stop; +0.5m is a comprehensive allowance for mouth exposure. Distinguish concrete overpour: JGJ 94-2008, 6.3.30's 0.8-1.0m overpour is underwater-concrete quality control and concrete-quantity caliber — logging-pipe takeoff does not add it.

3. Quick formulas

• Length (m): single tube = ground level - tip level + 0.5m; total = sum(tubes per pile x single length).
• Mass (t): total length x theoretical mass per meter (per design OD/wall; excluding fixings).
• Counts: per the drawing pile schedule; code bands are floors.

Applicable Boundaries

• Diameter bands are minimums: count per drawings; stricter locals govern (Guangdong d > 2500 >= 5; Tianjin bridges >= 3 at d >= 1000).
• Units differ: railway and Shenzhen in t (Shenzhen covers casing/caps); Hunan in m; Beijing in m (DN50). Check item units and work content before pricing.
• The length caliber is based on pre-driving ground (implicitly including empty-hole/overpour); local norms or contracts may override.
• Testing codes (how to embed) and consumption standards (how to measure) are separate systems; sonic method applicability and testing ratios are out of scope.

Further Reading

• JGJ 106-2014, 10.3.2 and commentary.
• TB 10218-2019, 5.3.1-5.3.3.
• TB/T 10823-2024 Vol. 2 volume notes, rule 6 and tube fabrication items.
• TB/T 10831-2024 Vol. 10 volume notes (bored piles, rule 8).
• DBJ/T 15-60-2019, 12.3.2; DB12/T 1122-2022, 8.3.1.
• DB11/T 2382-2024 Table A.3.2 (A-3-16); SJG 111.1-2022, 3.2.2.
• JGJ 94-2008, 6.3.30 (underwater overpour and tremie embedment).