Geotechnical Core Logging & Rock Mass Characterization, ASTM D6032 Deere RQD & Priest-Hudson
Deere Rock Quality Designation (RQD) & Joint Frequency
Calculate Total Core Recovery TCR (%), ASTM D6032 Measured Deere RQD (%), Priest & Hudson Theoretical RQD* (%) from Scanline Frequency lambda, and Palmstrom Volumetric Joint Count Jv.
92% Total Core Recovery does NOT mean good rock—fifteen 90 mm rubble sticks score 90%+ TCR yet ZERO percent Deere RQD!
**Don U. Deere (`1964`, `ASTM D6032`)** revolutionized diamond core logging (`NX` / `NQ` `>= 47.6` mm core diameter) by showing **Total Core Recovery `TCR% = (L_{recovered} / L_{run}) * 100%`** masks closely jointed rock! Instead, **Rock Quality Designation `RQD% = (SUM(L_{sound >= 100 mm}) / L_{run}) * 100%`** sums ONLY intact, hard core pieces **`>= 100` mm (`4` in) measured along the centerline between natural geological joints** (ignoring fresh mechanical drill/hammer breaks and dividing strictly by **Total Drill Run Length `L_{run}`**, NEVER by recovered length `L_{recovered}`!). When core is unavailable (exposed tunnel faces or quarry benches), **Priest & Hudson (`1976`)** proved negative-exponential joint spacing with **Linear Discontinuity Frequency `lambda`** (`joints/m`) yields **`RQD* = 100 * EXP(-0.1 * lambda) * (0.1 * lambda + 1)`**, while **Palmström (`1982`)** relates `RQD` to **3D Volumetric Joint Count `J_v = (115 - RQD) / 3.3`** (`joints/m³`)!
Verify on a `1,500` mm (`1.50` m) NQ3 Triple-Tube Core Run—Drill_Run_Advance `L_{run}` = 1,500 mm (B2), Total_Recovered_Core `L_{rec}` = 1,380 mm (B3), Sum_of_Sound_Sticks_`>=100mm` = 1,095 mm (B4), and Outcrop_Scanline_Frequency `lambda` = 8.5 joints/m (B5): `TCR` equals `92.0%` (E2), Measured `ASTM D6032` `RQD` equals `73.0%` (`Fair-to-Good`, E3—vs `79.3%` if erroneously divided by `1,380` mm!), Priest-Hudson Scanline `RQD*` equals `79.1%` (E4), and Palmström `J_v` equals `12.73` joints/m³ (E5)!
| ASTM D6032 Core Logging KPI (1,500 mm NQ3 Run: Moderately Jointed vs Fault Breccia) | Formula | Verified Output |
|---|---|---|
| Total Core Recovery TCR (%) | (Total_Recovered_mm / Total_Core_Run_mm) * 100 | 92.0% (76.0% in fault zone) |
| Measured Deere RQD (%) | (Sound_Sticks_100mm / Total_Core_Run_mm) * 100 | 73.0% Fair/Good (22.0% Very Poor!) |
| Priest-Hudson Scanline RQD* (%) | 100 * EXP(-0.1 * lambda_m) * (0.1 * lambda_m + 1) | 79.1% @ 8.5/m (30.8% @ 24/m) |
| Palmström Volumetric Joints Jv (/m³) | (115 - Measured_RQD_Pct) / 3.3 | 12.73 joints/m³ (28.18 sugar-cube!) |
ASTM D6032 Deere RQD, Priest-Hudson Poisson Spacing & Palmström Jv Formula
Validate `Core_Run L_{run}` in `[300, 6,000]` mm, `0 <= Sound_100mm <= Recovered <= Core_Run`, and `Scanline_Frequency lambda` in `[0.1, 60]` joints/m!
=LET(lr_n, B2, lt_r, B3, ls_d, B4, lm_j, B5, rq_m, (ls_d / lr_n) * 100, IF(OR(lr_n < 300, lr_n > 6000, lt_r < 0, lt_r > lr_n, ls_d < 0, ls_d > lt_r, lm_j < 0.1, lm_j > 60), "Invalid RQD Input", ROUND((115 - rq_m) / 3.3, 2)))Shattered Fault-Zone Rubble (`L_rec = 1,140` mm, `Sound >= 100mm = 330` mm, `lambda = 24`/m) Check
Core through a tectonic shear zone (`B3 = 1,140` mm, `B4 = 330` mm, `B5 = 24` joints/m): `TCR` E2 still looks respectable at `76.0%`, YET Deere `RQD` E3 collapses to **`22.0%` (`Very Poor Rock`, `< 25%`)**, Priest-Hudson `RQD*` E4 drops to `30.8%`, and Volumetric Joint Count `J_v` E5 surges to `28.18` joints/m³!
=IF(ISTEXT(E5), E5, ROUND(100 * EXP(-0.1 * B5) * (0.1 * B5 + 1), 1))Try the example
Use the original values or change them to test your understanding.