Are there any prophetic hadiths about throwing three handfuls of dirt on the grave during burial, and does this cause congestion?

Ibn Majah narrated with an authentic chain from Abu Hurairah that the Messenger of Allah, peace and blessings be upon him, prayed over a funeral and then came to the grave of the deceased and scooped (earth) onto it from the direction of its head three times. This has also been reported from Ali, may Allah be pleased with him. Ibn Qudamah mentioned in Al-Mughni that Ahmad (ibn Hanbal) scooped three handfuls onto the grave, emulating his action.