A　formula　for　the　variation　of　the　maximum　ground　settlement　with　the　depth　above　a　tunnel　is　proposed　based　on　data　from　25　field　project　cases　and　10　model　test　cases.　The　Gaussian　function　is　developed　by　introducing　the　proposed　formula　and　an　existing　formula　for　settlement　trough　width　coefficient,　to　predict　the　settlement　above　the　tunnel　in　the　transverse　section.　There　are　two　parameters,　n　and　k,　in　the　developed　Gaussian　function,　and　determination　methods　of　the　new　parameter　n　are　provided　for　clay　strata　and　sand　strata,　respectively.　The　application　method　of　the　developed　Gaussian　function　is　demonstrated　by　a　field　project　case.　Finally,　applicability　of　the　formula　for　the　maximum　ground　settlement　and　the　developed　Gaussian　function　are　validated　by　12　field　project　cases　and　9　tunnelling　model　test　cases　conducted　by　the　authors.