ECSLOPE - Slope Stability Analysis

This part of user manual describes how to use ECSLOPE for Slope Stability Analysis. ECPlus applications are designed as wizard type which is a step by step guided input procedure. If you are new to ECPlus applications, click here for general guidance.

Prerequisites: The user is expected to have a basic understanding of slope stability. ECPLUS uses Fellenius method of slope stability analysis in which the assumed slip circle is divided into number of slices.
The minimum input required to use this application is as follows:

• ❶ Geometry data such as slope height, angle, presence of hard layer / water level.
• ❷ Soil data such as pore pressure ratio, bulk unit weight, drained shear strength and effective shear resistance.
• ❸ Allowable factor of safety.

Following sections are presented with various input pages of ECSLOPE application with descriptions:

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Unit

This page allows to select the unit for analysis.

Unit

Select the unit for the analysis.
Available Units: ☉SI Unit (m, kN), and ☉Imperial (ft, kips).

☉SI Unit (m, kN): Select this option to carry out analysis in SI Units.
☉Imperial (ft, kips): Select this option to carry out analysis in Imperial Units.

While Switching Unit:

This option allows users to control what happens while switching between units.

☐  Reset to Default
This option will reset the input data for the new unit. This option is recommended if the job is new and no input data has been entered yet.
☐  Convert Inputs
This option allows to convert all the previously entered input data to the new unit.

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Slope Construction

This page allows the input of geometric shape of the slope.

Slope Height - H

Enter the height of the slope.
↔ Range: 0 to 100000 mm (0 to 4000 inches)

Slope Angle - β

Enter the angle of the slope.
↔ Range: 5 to 80

Top Surface Slope - β'

Enter the angle of the top surface.
↔ Range: 0 to 72

Depth of Upper Soil Layer - H_A

Enter the depth of the upper soil layer, if Layer is selected as 2 in Soil Properties
↔ Range: 0 to 100000 mm (0 to 4000 inches)

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Loads

This page allows the input of surcharge load on top surface of embankment.

Surcharge Loads

▽ Nil: Select this option when there is no surcharge load.
▽ Finite: Select this option when surcharge load of limited width acts on the top of the embankment.
▽ Infinite: Select this option when surcharge load is widely distributed on the top of the embankment

Distributed Load - Odl

Enter the distributed load imposed over the top surface.
↔ Range: 0 to 10000 kN/m² (0 to 210000 psf)

Start Length - Sl

Enter the starting length of the load.
↔ Range: 0 to 100000 mm (0 to 4000 inches)

Load Width - Lw

Enter the width of the distributed load, in case of surcharge load of finite width.
↔ Range: 0 to 100000 mm (0 to 4000 inches)

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Stability Analysis

This page allows the input of slip circle parameters.

☐  Auto Stability Analysis

On checking this option, the program will automatically determines the location and radius of the critical slip circle.

Number of Slices - N

Enter the number of slices to be considered for the analysis.
↔ Range: 5 to 100

Horizontal / Vertical Offset of Origin - x / y

Enter the horizontal / vertical offset of center of the slip circle from the origin.
↔ Range: -200000 to 200000 mm (-8000 to 8000 inches)

Radius - R

Enter the radius of the slip circle.
↔ Range: 1000 to 4000 mm (40 to 16000 inches)

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Analysis Setting

Setting for various Analysis Data such as soil properties and factor of safety are presented in this section. This setting pop-up can be accessed by clicking the bottom panel below the left navigation.

Soil Properties

Layers

Select the number of soil fill layers (1 or 2) from the drop down.

Soil Properties - Single Layer

▽ 1: Select this option to analyse slope with single soil layer.
▽ 2: Select this option to analyse slope with two layers.

Pore Pressure Ratio - R_u
↔ Range: 0 to 0.9

Unit Weight - γ_A
↔ Range: 5 to 50 kN/m³ (30 to 650 pcf)

Cohesion - C'_A
↔ Range: 0 to 1000 kPa (0 to 20000 ksf)

Angle of Internal Friction - Φ_A
↔ Range: 0 to 75 deg

Soil Properties - Two Layers

Pore Pressure Ratio - R_u
↔ Range: 0 to 0.9

Unit Weight - Upper - γ_A
↔ Range: 5 to 50 kN/m³ (30 to 650 pcf)

Unit Weight - Lower - γ_B
↔ Range: 5 to 50 kN/m³ (30 to 650 pcf)

Cohesion - Upper - C'_A
↔ Range: 0 to 1000 kPa (0 to 20000 ksf)

Cohesion - Lower - C'_B
↔ Range: 0 to 1000 kPa (0 to 20000 ksf)

Angle of Internal Friction - Upper - Φ_A
↔ Range: 0 to 75 deg

Angle of Internal Friction - Lower - Φ_B
↔ Range: 0 to 75 deg

Hard Surface and Water

☐  Include Hard Surface
On checking this option, hard surface will be considered at specified depth from the base.
Hard Layer Depth - H_L
↔ Range: 0 to 100000 mm (0 to 4000 in)

☐  Include Water Level
On checking this option, the buoyancy effect of the water will be considered for the specified height from the base.
Water Level Height - W
↔ Range: -50000 to 100000 mm (-2000 to 4000 in)

Factor of Safety

Factor of Safety - FOS
↔ Range: 0 to 100

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Error Handling

Errors and Warnings are generated to prevent any inadvertent error in the input data. This section describes how to handle the errors and warnings. These errors are displayed at the bottom of the input page when the data in one or more input fields invalidate each other.