Editing Civil engineering (section)

===Geotechnical engineering===
{{Main|Geotechnical engineering}}
[[File:Soil-phase-diagram.svg|thumb|A phase diagram of soil indicating the weights and volumes of air, soil, water, and voids.]]
''Geotechnical engineering'' studies rock and soil supporting civil engineering systems. Knowledge from the field of [[soil science]], materials science, [[mechanics]], and [[hydraulics]] is applied to safely and economically design [[foundation (engineering)|foundations]], [[retaining wall]]s, and other structures. Environmental efforts to protect [[groundwater]] and safely maintain landfills have spawned a new area of research called geo-environmental engineering.<ref name="mitchell">{{cite book |last=Mitchell |first=James Kenneth |date=1993 |title=Fundamentals of Soil Behavior |edition=2nd |publisher=John Wiley and Sons |pages=1–2}}</ref><ref>{{cite book |last1=Shroff |first1=Arvind V. |last2=Shah |first2=Dhananjay L. |date=2003 |title=Soil Mechanics and Geotechnical Engineering |publisher=Taylor & Francis |pages=1–2}}</ref>

Identification of soil properties presents challenges to geotechnical engineers. [[Boundary condition]]s are often well defined in other branches of civil engineering, but unlike steel or concrete, the material properties and behavior of soil are difficult to predict due to its variability and limitation on [[geotechnical investigation|investigation]]. Furthermore, soil exhibits nonlinear ([[stress (physics)|stress]]-dependent) [[shear strength (soil)|strength]], stiffness, and dilatancy (volume change associated with application of [[shear stress]]), making studying [[soil mechanics]] all the more difficult.<ref name="mitchell"/> Geotechnical engineers frequently work with professional [[geologists]],  [[Geological Engineering]] professionals and soil scientists.<ref>{{cite web |title=Geotechnical/Geological Engineering |url=https://www.ausimm.com.au/content/docs/careers_booklet_geotgeoleng.pdf |archive-url=https://web.archive.org/web/20080720101333/http://www2.ausimm.com.au/content/docs/careers_booklet_geotgeoleng.pdf |archive-date=2008-07-20 |url-status=live |website=Professional Careers in the Mineral Industry |publisher=The Australasian Institute of Mining and Metallurgy |access-date=30 May 2018}}</ref>