Compaction Equipment by Soil Type
| Soil | Equipment | Avoid | Passes |
|---|
| Gravel (GW, GP) | Smooth drum vib. (high amp) | Padfoot | 4–6 |
| Sand (SP, SM) | Smooth drum vib. (high freq) | Padfoot | 4–8 |
| Silty sand (SM) | Smooth drum vib. | — | 6–8 |
| Lean clay (CL) | Padfoot static/vib. | Smooth drum alone | 6–10 |
| Fat clay (CH) | Padfoot static | Any vibratory | 8–12 |
| Silt (ML) | Padfoot vib. (low amp) | High-amp vib. | 6–10 |
| Granular A/B | Smooth drum vib. | Static only | 4–6 |
Max Lift Thickness (Compacted)
| Material | Ride-On (≥10t) | Walk-Behind | Rammer |
|---|
| Granular A | 200–300 mm | 100–150 | 100–150 |
| Gran. B Type I | 250–350 mm | 150–200 | 150 |
| Gran. B Type II | 300–400 mm | N/R | N/E |
| Sand (SW, GW) | 250–350 mm | 150–200 | 150–200 |
| Clay (CL) | 150–200 mm | N/R | 100–150 |
| Fat clay (CH) | 150 mm max | N/R | 100 max |
N/R = not recommended; N/E = not effective. Loose thickness 20–35% greater.
Proctor Testing
| Parameter | Standard (D698) | Modified (D1557) |
|---|
| Hammer | 2.5 kg / 305 mm drop | 4.54 kg / 457 mm drop |
| Layers / blows | 3 / 25 | 5 / 25 |
| Energy | 600 kN·m/m³ | 2,700 kN·m/m³ |
| Typical use | Cohesive, residential | Granular, commercial |
95% Standard ≠ 95% Modified. Modified yields 100–200 kg/m³ higher density. Always verify which standard is specified.
Field Testing Frequency (OPSS 501)
| Application | Min. Frequency |
|---|
| Structural fill (footings/slabs) | 1 per 250 m² per lift |
| General site fill | 1 per 500 m² per lift |
| Trench backfill | 1 per 50 lin. m per lift |
| Granular base/subbase | 1 per 250 m² per lift |
Nuclear Gauge Modes
- Direct transmission: Rod in hole, 150–300 mm. Always use for compaction.
- Backscatter: Surface only, top 75–100 mm. For asphalt only.
Ontario Granular Specs (OPSS.MUNI 1010)
- Granular A: 19 mm top size, crushed, 2–8% fines. Base course under slabs/pavements.
- Granular B Type I: 50 mm top size. Subbase layer. Crushed or pit-run.
- Granular B Type II: 150 mm top size. Thick subbase, access roads, bridging soft subgrade.
- Granular M: 19 mm top size, ≤5% fines. Pipe bedding. No stones >19 mm for PVC.
- RCA: Max 50% in Gran. A; not permitted in pipe bedding (Granular M).
Typical Church Pavement Section
150 mm Gran. A over 300 mm Gran. B Type I over prepared subgrade.
Under Building Slab
150–200 mm Gran. A over compacted structural fill.
Bearing Capacity (OBC Table 9.4.4.1)
| Soil / Rock | kPa |
|---|
| Sound rock (granite, limestone) | 500 |
| Dense gravel / sand-gravel | 150 |
| Compact coarse sand | 100 |
| Loose fine sand / stiff clay | 50–75 |
| Soft clay / silt | 25 |
Frost Depths (OBC)
- Southern ON (Windsor–Toronto): 1.2 m
- Central ON (Barrie, Peterborough): 1.4–1.5 m
- Northern ON (Sudbury+): 1.8 m+
Safety & Regulatory
- Nuclear gauge: CNSC licensed operators only. 5 m exclusion if damaged. Personal dosimeters required.
- Jumping jack rammers: 2 hr max shifts, mandatory rotation. 95–105 dBA — hearing protection required.
- O. Reg. 406/19 (Excess Soil): >2,000 m³ leaving site requires QP oversight, sampling, tracking registry. Fines $100K/day.
- Roller sinking >25 mm: STOP. Soil too wet. Disc/aerate and dry before resuming.
- Changed soil conditions: If soil differs from geotech report, stop work and notify engineer immediately.
Pro Tips
- GPS machine control reduces earthwork time 25–40%. GNSS: ±25–50 mm vert. RTS: ±3–5 mm for fine grading.
- Padfoot "walking out": When roller rides on surface instead of sinking, lift is fully compacted. Most reliable visual check for clay.
- New Proctor required every time borrow source changes. Budget 5–7 business days for lab turnaround.
- Drainage from buildings: Min 2% slope within 2 m of building (OBC 9.14.6.1). Min 1% in swales.