Tire Tread Comprising Undulating Grooves

A tread (1) for a heavy-duty vehicle tyre, having a tread surface (10) and an undulating groove (2) formed therein, having, when new, external cavities (21) open onto the tread surface (10) and internal cavities (22) entirely situated there-beneath when new, these cavities (22) connected to cavities (21) by linking cavities (23), each external cavity (21) intersecting the tread surface (10) along a corner edge contour delimiting an opening (210) having two end regions (A1, A2) and a surface area Se measured on the tread surface (10). In each end region (A1, A2) at least one thin blade (41, 42) of rubbery material is formed which is secured to at least one of the walls delimiting the undulating groove to reduce the surface area of the opening (210) of each external cavity (21) viewed from the tread surface (10) when new.