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earth-pressure-calculator skill

/plugins/babysitter/skills/babysit/process/specializations/domains/science/civil-engineering/skills/earth-pressure-calculator

This skill calculates lateral earth pressures for retaining structures using Rankine, Coulomb, and seismic methods to guide safe, efficient design.

npx playbooks add skill a5c-ai/babysitter --skill earth-pressure-calculator

Review the files below or copy the command above to add this skill to your agents.

Files (1)
SKILL.md
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---
name: earth-pressure-calculator
description: Earth pressure calculation skill for retaining structures using classical and seismic methods
allowed-tools:
  - Read
  - Write
  - Glob
  - Grep
  - Edit
  - Bash
metadata:
  specialization: civil-engineering
  domain: science
  category: Geotechnical Analysis
  skill-id: CIV-SK-012
---

# Earth Pressure Calculator Skill

## Purpose

The Earth Pressure Calculator Skill determines lateral earth pressures on retaining structures using Rankine, Coulomb, and seismic methods for design of retaining walls and basement walls.

## Capabilities

- Active earth pressure (Rankine, Coulomb)
- Passive earth pressure
- At-rest earth pressure
- Surcharge effects
- Layered soil conditions
- Seismic earth pressure (Mononobe-Okabe)
- Sloping backfill effects
- Water pressure considerations

## Usage Guidelines

### When to Use
- Designing retaining walls
- Analyzing basement walls
- Evaluating excavation support
- Assessing seismic pressures

### Prerequisites
- Soil parameters available
- Wall geometry defined
- Surcharge loads identified
- Groundwater level known

### Best Practices
- Select appropriate theory
- Consider wall movement
- Include seismic where required
- Account for drainage

## Process Integration

This skill integrates with:
- Retaining Wall Design
- Foundation Design

## Configuration

```yaml
earth-pressure-calculator:
  theories:
    - rankine
    - coulomb
    - log-spiral
  pressure-states:
    - active
    - passive
    - at-rest
  seismic:
    - mononobe-okabe
    - wood
```

## Output Artifacts

- Pressure diagrams
- Force calculations
- Moment summaries
- Seismic increment values

Overview

This skill calculates lateral earth pressures for retaining structures using classical and seismic methods to support safe, code-informed design. It produces pressure distributions, resultant forces, and summary moments for active, passive, and at-rest states and includes surcharge, layered soils, and groundwater effects.

How this skill works

The calculator accepts soil parameters, wall geometry, surcharge loads, and groundwater location, then applies Rankine, Coulomb, and Mononobe-Okabe formulations as requested. It computes pressure profiles (including sloping backfill and layered soils), combines soil and hydrostatic contributions, and outputs force and moment summaries plus seismic increments when enabled.

When to use it

  • Designing or checking retaining walls and basement walls
  • Evaluating earth pressures for excavation support and shoring
  • Estimating passive reactions for foundations and anchors
  • Assessing additional loads from surcharges and layered soils
  • Including seismic loading in regions with earthquake risk

Best practices

  • Provide accurate soil unit weights, friction angles, and cohesion for each layer
  • Choose Rankine for simple, planar backfills; use Coulomb when wall friction or wall inclination is significant
  • Include groundwater and drainage conditions; convert to effective stresses where appropriate
  • Enable seismic methods (Mononobe-Okabe) only when dynamic conditions are relevant and use code-consistent coefficients
  • Review wall movement assumptions before using active or at-rest solutions

Example use cases

  • Calculate active earth pressure distribution for a 4 m retaining wall with sloping backfill and a uniform surcharge
  • Estimate seismic lateral increments on a basement wall using Mononobe-Okabe for a specified peak ground acceleration
  • Model layered soil profile behind a wall to obtain combined pressure diagrams and resultant forces
  • Compute passive resistance behind a spread footing for lateral load checks
  • Include hydrostatic pressure when groundwater intersects the retained zone and assess drainage impact

FAQ

Which theory should I use for a simple vertical wall with horizontal backfill?

For a vertical wall and horizontal backfill with negligible wall friction, Rankine is quick and appropriate; use Coulomb if you expect significant wall friction or sloping wall faces.

How are groundwater and surcharge loads handled?

Groundwater is treated as a hydrostatic pressure contribution; surcharge loads are added as uniform surface pressures. Use effective stress inputs if you want pore pressure effects isolated from soil strength.