Earthmoving/ trenching construction, safety: Trench shield/box constructed of side walls of double steel plates with hollow core, tapered cutting edges at bottom, and large diameter pipe interior support to resist exterior soil pressures. Trench shield extends from bottom of trench to above top of excavation and protects the workers inside it from possible trench wall cavein. Dark spots on side walls are rain drops on this rainy day. First Street, Ann Arbor, Michigan 2006.

Earthmoving/ trenching construction, safety: Trench shield/box constructed of side walls of double steel plates with hollow core, tapered cutting edges at bottom, and large diameter pipe interior support to resist exterior soil pressures. Trench shield extends from bottom of trench to above top of excavation and protects the workers inside it from possible trench wall cavein. Dark spots on side walls are rain drops on this rainy day. First Street, Ann Arbor, Michigan 2006.