Final answer:
Trench walls that have water seeping from them tend to be less stable due to the weakening of the soil and increased pressure on the wall.
Step-by-step explanation:
Trench walls that have water seeping from them tend to be less stable. When water seeps into the walls of a trench, it can weaken the soil and cause it to become less compact, resulting in a loss of stability. The water can also create additional pressure on the wall, increasing the likelihood of collapse or erosion.