No, physical and chemical weathering processes are not independent of each other. Very rarely does any one of these processes ever operate completely by itself, though quite often a dominance of one process can be seen.

Physical weathering processes depend on applied forces like gravitational forces, expansion forces due to temperature changes, and water pressures. These forces lead to rock fracture, primarily caused by thermal expansion and pressure release. When rocks fracture, new surfaces are created.

Chemical weathering processes like solution, carbonation, hydration, oxidation and reduction act on rocks to decompose, dissolve or reduce them. Water and air (oxygen and carbon dioxide) along with heat must be present to speed up all chemical reactions.

The interdependence is clearly demonstrated through biological weathering. Burrowing and wedging by organisms like earthworms, termites, and rodents help in exposing new surfaces to chemical attack and assist in the penetration of moisture and air. Human activities help in creating new contacts between air, water and minerals. Plant roots mechanically break materials apart, while decaying matter produces acids that enhance chemical decay.

Thus, physical and chemical weathering processes work together in a complementary manner, with each process facilitating and accelerating the other.