Using　the　complex　variable　method,　an　elastic　analytical　solution　of　the　ground　displacement　caused　by　a　shallow　circular　tunneling　is　derived.　Non-symmetric　deformation　relative　to　the　horizontal　center　line　of　the　tunnel　cross-section　is　used　as　a　boundary　condition.　A　comparison　between　the　proposed　analytical　method　and　the　Finite　Element　Method　is　carried　out　to　validate　the　rationality　of　the　obtained　analytical　solution.　Two　parameters　in　the　Peck　formula,　namely　the　maximum　settlement　of　the　ground　surface　center　and　the　width　coefficient　of　settlement　curve,　are　fitted　and　determined.　We　propose　a　modified　Peck　formula　by　considering　three　input　parameters,　namely　the　tunnel　depth,　tunnel　radius,　and　the　tunnel　gap.　The　influence　of　these　three　parameters　on　the　modified　Peck　formula　is　analyzed.　The　applicability　of　the　modified　Peck　formula　is　further　investigated　by　reference　to　six　engineering　projects.　The　ground　surface　displacement　obtained　by　the　explicit　Peck　formula　is　in　good　agreement　with　the　field　data,　and　the　maximum　error　is　only　1.3　cm.　The　proposed　formula　can　quickly　and　reasonably　predict　the　ground　surface　settlement　caused　by　tunnelling.