Heavy-duty vehicle tire tread with improved robustness

A heavy duty vehicle tire tread intended to come into contact with the ground via a tread surface, comprising:

• cuts delimiting raised elements, and having a thickness (E), along a radial direction (ZZ′), between the tread surface and a bottom surface,
• the tread comprising:
• at least one substantially longitudinal cut having, on the tread surface, a mean plot (M1), the tangent of which at any point forms an angle at most equal to 45° with a longitudinal direction (XX′) of the tread (1),
• the at least one substantially longitudinal cut comprising at least one external cavity open onto the tread surface along an open section having a closed contour,
• each external cavity being connected to two substantially longitudinal sipes, extending along the mean plot (M1) of the substantially longitudinal cut and intersecting the contour at two connection points (J1, J2),
• the open section of each external cavity having a length (B), measured along a first straight line (D1) passing through the two connection points (J1, J2), and a width (A) at most equal to the length (B) and measured along a second straight line (D2) perpendicular to the first straight line (D1),
• at least one oblique sipe opening into each axial side of each external cavity at a respective connection point, and having, on the tread surface, a mean plot (M2) that is not parallel to the first straight line (D1) and intersects the contour at a connection point (I), each connection point defined by a pair of walls of each external cavity that extend in different axial and/or circumferential directions,
• wherein the mean plot (M2) of each oblique sipe forms an angle (A1, A2) strictly greater than 90° with at least two straight lines (T1, T2) tangential to the contour respectively at two points (I1, I2) of the contour that are positioned on either side of the mean plot (M2) of the oblique sipe and at a curvilinear distance (d1, d2) from the connection point (I) at most equal to 2 mm,
• wherein sipes have a width such that facing walls of material that delimit them come into contact with one another at least partially when the tread enters the contact patch, and
• wherein the at least one oblique sipe opening into each axial side of each external cavity are symmetrically arranged with respect to the mean plot (M1) of the substantially longitudinal cut.