The ITA general Assembly approved the proposal for establishing Working Group 23 on «Design and Construction of Shafts» in May 2019 at the World Tunnelling Congress in Naples.  
Following the first WG 23 meeting in Naples, the need for defining common terms was raised and it was decided to prepare a document to explain and develop the correct terminology and nomenclature for shaft design and construction.  
It was also discussed that suitable classifications for shafts based on their geometry, application, ground conditions, and construction methods was needed for a more uniform understanding of design and construction implications. 
This document is prepared in response to the above mentioned needs and provides common definitions for relevant terms in addition to introducing different types of classification systems for shafts that can be implemented during design and construction of these structures. 
The document contains contributions of various individuals. Work has been coordinated by Siamak Hashemi (Animateur of WG 23) and Jamal Rostami. Tarcisio Celestino was the Tutor of WG 23.