To add new web application in SharePoint 2010 with PowerShell using New-SPWebApplication
New-SPWebApplication –applicationpool <Application pool name> -name <New App Name>
-applicationpoolaccount <service account> -port <Port Number>
Sample Command Line to create new Web Application in SharePoint 2010 using PowerShell
New-SPWebApplication –applicationpool SharePoint-80 -name SharePoint-80
–applicationpoolaccount vSharePoint\SPAdmin -port 80