The SQL server Log folder is expanding because of the SQL Dump files (what to do with it ?)

The "Log" folder SIZE in the SQL server root directory (X:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Log) becomes too big , ~80 GB.

When I checked it, I see that there are a lot of SQLDumpxxxx.mdmp /SQLDumpxxxx.txt files in that folder.

what to do with them ? can I delete them and if it is good thing to do ?