Soldier piles are vertical structural elements used in construction and civil engineering to support excavations or foundations. They are typically made of steel or reinforced concrete and are driven into the ground to create a strong barrier against soil movement. This technique is often employed in areas with unstable soil or where deep excavations are necessary. These piles are commonly used in conjunction with other support systems, such as lagging or sheet piles, to create a complete retaining wall. Soldier piles help maintain the integrity of the surrounding soil and prevent collapse during construction projects, ensuring safety and stability.