approach trenches in a sentence

1. With an island traverse, the approach trench splits to go around both sides of a traverse before coming together again.
2. On an approach trench, that is, a trench leading from the rear to the frontline or firing trench, defenders may construct an island traverse.
3. During the unsuccessful siege, he suffered his only wound in seven years of service, bayonetted in the buttocks during an assault by the fort's defenders on the approach trench that he was constructing.
4. However, this plan did not take into account the fact that the fortress was located on a rocky promontory where it was impossible to dig approach trenches and that a large ditch cut into the rock protected the fort on the land side.
5. It's difficult to find approach trenches in a sentence.