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 width W D and a radial depth H D, and elements in relief separated by the cuts, - the cuts, the width W D of which is at most equal to 20% of the radial depth H D and the radial depth H D of which is at least equal to 50% of the radial thickness H T, referred to as effective cuts, having a cumulative length L D measured on a radially outer surface of the tread, - the tread having a degree of surface siping TL, expressed in m/m 2, equal to the ratio between the cumulative length L D of the effective cuts and the area A of the radially outer surface of the tread equal to 2ΠR E *W T, where R E is the external radius of the tyre, - the crown reinforcement comprising a protective reinforcement, a working reinforcement and a hoop reinforcement, - the protective reinforcement, which is radially outermost, comprising at least two protective layers (41, 42), formed of 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), formed of inelastic 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), formed of metallic reinforcers that form an angle at most equal to 15° with the circumferential direction (XX'), characterized in that the degree of surface siping TL of the tread is at least equal to 3 m/m 2, and in that a coupling ratio C, equal to the ratio between the maximum value R max of the breaking strengths R of the protective layers (41, 42) and the degree of surface siping TL of the tread, is at least equal to 30000 daN. - the tread, having a radial thickness H T at least equal to 60 mm, comprising cuts having a width W D and a radial depth H D, and elements in relief separated by the cuts, - the cuts, the width W D of which is at most equal to 20% of the radial depth H D and the radial depth H D of which is at least equal to 50% of the radial thickness H T, referred to as effective cuts, having a cumulative length L D measured on a radially outer surface of the tread, - the tread having a degree of surface siping TL, expressed in m/m 2, equal to the ratio between the cumulative length L D of the effective cuts and the area A of the radially outer surface of the tread equal to 2ΠR E *W T, where R E is the external radius of the tyre, - the crown reinforcement comprising a protective reinforcement, a working reinforcement and a hoop reinforcement, - the protective reinforcement, which is radially outermost, comprising at least two protective layers (41, 42), formed of 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), formed of inelastic 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), formed of metallic reinforcers that form an angle at most equal to 15° with the circumferential direction (XX'), characterized in that the degree of surface siping TL of the tread is at least equal to 3 m/m 2, and in that a coupling ratio C, equal to the ratio between the maximum value R max of the breaking strengths R of the protective layers (41, 42) and the degree of surface siping TL of the tread, is at least equal to 30000 daN.