http://stackoverflow.com/questions/16278720/logback-create-log-files-inside-folder-having-name-as-current-date
As mentioned in the documentation for fileNamePattern, you can specify multiple %d tokens so as put the date in the folder name of the archive filename:
<fileNamePattern>${PROJECT_HOME}\\projectname\\audits\\%d{yyyy-MM, aux}\\myproject_%d{yyyy-MM-dd}.%i.zip</fileNamePattern>
Note that only one %d token can be primary, all other tokens must be marked as auxiliary by passing the 'aux' parameter.
But if you also want to put it in the file name of the non-arhcive filename, then you have two options:
1. use a <timestamp /> element to set a variable which you use in the path. But this timestamp will only be set once at startup, so it's good for batch runs but not for services.
2. Do like (1) above, but wrap the <appender/> and the <timestamp /> with a SiftingAppender, which will enable the timestamp to be re-evaluated, if using version of logback >=1.0.12. Not sure exactly how you'd want to configure the SiftingAppender. But hopefully that will put you on the right track.