Excavation Slope

Reference data and engineering information about excavation slope for miscellaneous applications.

excavationslope

Overview

Engineering reference data for Excavation Slope in miscellaneous.

Key Formulas

Unit Conversion

$y = x \cdot k$

Multiply by conversion factor.

Linear Interpolation

$y = y_1 + \frac{(x - x_1)(y_2 - y_1)}{x_2 - x_1}$

Estimate between two known points.

Percentage

$p = \frac{\text{part}}{\text{whole}} \times 100\%$

Part as fraction of whole.

Symbol	Description	Unit
$x$	Input value	—
$y$	Output value	—
$k$	Conversion factor	—

Recommended maximum excavation slope ratios based on soil type.
Type of Soil	Slope Ratio (Horizontal : Vertical)
Solid rock, shale or cemented sand & gravels	0 : 1 (Vertical)
Compact angular gravels	1/2 : 1
Average soils (Recommended)	1 : 1
Compact sharp sand	1.5 : 1
Well-rounded loose sand	2 : 1

Worked Example: Slope Calculation for Sharp Sand

For an excavation in compact sharp sand, the recommended slope ratio is *1.5 : 1 (horizontal : vertical). This means for every 1 unit of depth, the excavation must slope back 1.5 units horizontally.

Calculation: For a depth $d$ of 10 ft:

\text{Slope Distance (Horizontal)} = d \times \text{Slope Ratio} = 10 \, \text{ft} \times 1.5 = 15 \, \text{ft}

Therefore, for a 10 ft deep trench, the base must be set back 15 feet from the top edge for safety.

References

Original Source

Source: engineeringtoolbox.com