Snail Software

The soil nail wall analysis and design software, Snail, can be downloaded here. External Users must purchase the Snail software license and obtain the software security dongle to use the software. To purchase the license, please follow the Instruction to Purchase Snail. Then, email the payment receipt and the completed Order Form to

Please click the following links to download the documents needed to obtain Snail:

Snail Download

For External Users For Caltrans Users
  • Submit an IT service request ticket via Service Desk Ticket Request or Service Desk Email.

  • Request for installation of Snail,
  • Include the Caltrans assigned computer name of your computer, and
  • Request the ticket to be assigned to HQ IT.
  • Release Memo
Supporting Documents

This software is for stability analysis of soil nails and analysis of structural facing of soil nail walls. Snail was first developed and maintained by Caltrans since circa 1989. The software only runs under the Windows 7, 8 and 10 operating systems on a computer designed to run Windows as the native operating system. It will not function on a computer running Windows through virtual machine software.

Snail implements force limit equilibrium for the stability analysis of soil nails. For structural facing analysis and design, Snail follows the procedure presented in Soil Nail Walls Reference Manual, FHWA-NHI-14-007, FHWA GEC 007, February 2015.

Snail includes the following main features:

  • Options of using Load and Resistance Factor Design (LRFD, GEC No. 7 2015 approach) or Allowable Stress Design (ASD) for both geotechnical soil nails and structural facing analysis and design
  • Performs soil nails analysis using bi-linear or tri-linear search surfaces
  • Performs structural facing analysis with or without soil nails analysis
  • Presents the controlling modes in soil nails analysis
  • Graphically presents the calculated most critical search surface or any user selected search surface, and corresponding factors of safety (FoS) or capacity demand ratios (CDR)
  • Allows parametric study of inter-slice force inclination
  • Allows both U.S customary and metric units
  • Provides graphic and text outputs