Final answer:
Heaving and squeezing can still occur even with proper shoring or shielding, due to pressures from surrounding soil or environmental conditions.
Step-by-step explanation:
The statement is true. Heaving or squeezing can occur even when shoring or shielding has been properly installed. Despite the proper installation of these protective systems, the force of the surrounding soil or environmental conditions may still cause the ground to move.
This movement can result in heaving, which is an upward movement of the ground, or squeezing, which is a lateral pressure that can compress the shoring or shielding systems. The significance of this is similar to the effect shear has on structures like shelves, dams, or levees, where such forces could lead to a collapse or landslide if not considered and mitigated properly.