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Table 1 The physical parameters of the underground rock–soil layers
From: Effect of groundwater forced seepage on heat transfer characteristics of borehole heat exchangers
Soil media | Depth of distribution σ (m) | Horizontal permeability kXY (m2) | Porosity εs | Volumetric heat capacity of the soil csρs (J m−3 K−1) | Thermal conductivity λs (W m−1 K−1) | Longitudinal thermal dispersivity αL (m) | Transverse thermal dispersivity αT (m) | Initial temperature of soil layer TS0/℃ | |
|---|---|---|---|---|---|---|---|---|---|
Clay | 0–9 | 5.0 × 10–14 | 0.45 | 2.7 × 106 | 1.10 | 0.3 | 0.03 | 16 | |
Silty clay | 9–24 | 5.0 × 10–14 | 0.40 | 3.2 × 106 | 1.20 | 0.3 | 0.03 | 16 | |
Fine sand | 24–44 | 1 × 10–12 | 0.35 | 1.4 × 106 | 0.95 | 3.0 | 0.30 | 16 | |
Silty sand | 44–80 | 8.0 × 10–13 | 0.38 | 2.4 × 106 | 1.60 | 0.1 | 0.01 | 16 | |
Silty clay | 80–83 | 5.0 × 10–14 | 0.40 | 3.2 × 106 | 1.20 | 0.3 | 0.03 | 16 | |