Tyre for a heavy vehicle of construction plant type, comprising a tread and a crown reinforcement radially on the inside of the tread: - the tread, having a radial thickness H T at least equal to 60 mm, comprising cuts having a radial depth H D and a width W D, and elements in relief separated by the cuts, - at least some of the cuts, referred to as effective cuts, having a radial depth H D at least equal to 50% of the radial thickness H T and a width W D at most equal to 20% of the radial depth H D, - the crown reinforcement comprising a protective reinforcement, a working reinforcement and a hoop reinforcement, - the protective reinforcement, which is radially outermost, comprising two protective layers (41, 42), in contact with one another over a median axial width W C, comprising elastic metallic reinforcers, that form an angle of between 15° and 45° with the circumferential direction (XX'), each protective layer (41, 42) having a breaking strength R per unit of layer width, expressed in daN/m, R max being the maximum value of the breaking strengths R of the protective layers (41, 42), - the working reinforcement comprising at least two working layers (51, 52), comprising inextensible metallic reinforcers that are crossed from one working layer to the next and form an angle of between 15° and 45° with a circumferential direction (XX') of the tyre, - the hoop reinforcement comprising at least one hooping layer (61, 62), comprising metallic reinforcers that form an angle at most equal to 15° with the circumferential direction (XX'), characterized in that the median degree of surface siping TL C of the tread, defined as the ratio between the cumulative length L DC of the effective cuts, present on a median portion of tread having an axial width equal to W C, and a median area A C of the radially outer surface of the tread equal to 2ΠR E ∗ W C, where R E is the external radius of the tyre, is at least equal to 5 m/m 2 and in that the coupling ratio C C, defined as the ratio between the maximum value R max of the breaking strengths R of the protective layers (41, 42) and the median degree of surface siping TL C of the tread, is at least equal to 18 000 daN. - the tread, having a radial thickness H T at least equal to 60 mm, comprising cuts having a radial depth H D and a width W D, and elements in relief separated by the cuts, - at least some of the cuts, referred to as effective cuts, having a radial depth H D at least equal to 50% of the radial thickness H T and a width W D at most equal to 20% of the radial depth H D, - the crown reinforcement comprising a protective reinforcement, a working reinforcement and a hoop reinforcement, - the protective reinforcement, which is radially outermost, comprising two protective layers (41, 42), in contact with one another over a median axial width W C, comprising elastic metallic reinforcers, that form an angle of between 15° and 45° with the circumferential direction (XX'), each protective layer (41, 42) having a breaking strength R per unit of layer width, expressed in daN/m, R max being the maximum value of the breaking strengths R of the protective layers (41, 42), - the working reinforcement comprising at least two working layers (51, 52), comprising inextensible metallic reinforcers that are crossed from one working layer to the next and form an angle of between 15° and 45° with a circumferential direction (XX') of the tyre, - the hoop reinforcement comprising at least one hooping layer (61, 62), comprising metallic reinforcers that form an angle at most equal to 15° with the circumferential direction (XX'),