Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The trench in a dream indicates a man who protects his family and wealth. It may also indicate travel. Falling into it indicates falling into cunning or hardship.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The trench indicates a difficult matter that cannot be overcome except with hardship. Crossing it indicates salvation from hardship.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The trench is interpreted as worry and grief. Getting out of it is relief and salvation.