How are erosional glacial landforms formed, for example a u-shaped valley?

erosional glacial landforms are formed through erosional processes including both physical and chemical weathering, such as freeze-thaw weathering, with ice eroding away rock and debris to produce a landform in a shape which we recognise it. For example a u-shaped valley is formed when glaciers flow down a valley and erode rock from beneath the glacier, and smoothing the rock surface left behind, producing a valley with a U shape.