SNAP_2 (SOIL NAIL ANALYSIS PROGRAM)
Barry D. Siel
March 2014 (Revised December 2016)
Soil nail walls are internally stabilized earth-retaining structures. Soil nail walls use a top-down construction with in situ reinforcement to support temporary or permanent excavations. In certain conditions, soil nailing is a viable alternative to other ground anchor systems, considering technical feasibility, cost, and construction duration.
Although the use of soil nail walls for highway applications has increased dramatically in the past decade, computer programs for the design of soil nail walls are not up to date. The main objective of this work is to develop a state-of-the-practice computer program, SNAP_2 (Soil Nail Analysis Program) for designing all components of soil nail retaining structures, including nail and facing elements. The program will evaluate the internal and external wall stability (including limit-equilibrium global slope stability) based on the current standards in the ASD method. In addition, the program may be used to evaluate verification and proof field test results. All design and evaluation procedures are according to the FHWA guidelines presented in 1) The Manual for Design and Construction of Soil Nail Walls, Report No. FHWA-SA-96-069R, and 2) Geotechnical Engineering Circular No. 7 – Soil Nail Walls Reference Manual, Report No. FHWA-NHI-14-007 (document available below.)
This user’s manual discusses the theoretical basis for the computer program, gives a comparison of available soil nail wall design guidelines, discusses program execution including inputs and outputs, and includes two worked examples to demonstrate use of the program.
Victor Elias, P.E.; Barry R. Christopher, Ph.D., P.E. and Ryan R. Berg, P.E.
The purpose of Demonstration Project 103 was to introduce the concept of soil nailing use into the American transportation construction practice. The Manual for Design and Construction Monitoring of Soil Nail Walls ( FHWA-SA-96-069R) and Soil Nailing Field Inspectors Manual (FHWA-SA-93-068) were published as a part of this demonstration project. Also, GOLDNAIL (soil nail design software) was developed and distributed through this demonstration project. This report is a summary of the activities of Demonstration Project 103. It includes the history, concept, construction procedures and cost data for soil nail walls.
Carlos A. Lazarte, PhD, PE, GE; Helen Robinson, PE; Jesús E. Gómez, PhD, PE; Andrew Baxter, PE, PG; Allen Cadden, PE; Ryan Berg, PE
FHWA GEC 007
This document presents information on the analysis, design, and construction of permanent soil nail walls in highway applications. The main objective is to provide practitioners in this field with sound and simple methods and guidelines that will allow them to analyse, design, construct, and inspect safe and economical structures. This document updates the information contained in FHWA0-IF-03-017 (Lazarte et al. 2003). The focus is on soil nailing techniques that are commonly used in U.S. practice. The contents of this document include: an introduction; chapters on applications and feasibility, construction materials and methods, information required for design, analysis and design of soil nail walls, corrosion protection; and chapters on contracting approach, technical specifications and design examples. This manual introduces a framework for the design of soil nail walls that takes into account factors of safety used in the ASD method while integrating LRFD principles.
James A. Porterfield; David M. Cotton, P.E.; R. John Byrne, P.E.
The purpose of this manual is to provide field inspectors with the knowledge necessary to effectively monitor and document the construction of soil nail retaining walls.
The manual provides information useful to both the experienced and inexperienced soil nail inspector. The manual is organized into two main parts: Pre-construction Preparation and Construction Inspection. Check-lists are provided throughout the Construction Inspection sections of the manual which summarize key items discussed in the text. The inspector is encouraged to copy the check-lists for use during construction.
Appendix A contains blank forms that can be used for proper documentation and testing during soil nail wall construction. Appendix B contains examples of completed forms.
Construction inspectors and engineers from California, Oregon, Texas, and Washington State departments of transportation contributed to this manual. The International Association of Foundation Drilling also provided input from the industry perspective.