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 , 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 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 , - the working reinforcement comprising at least two working layers , 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 , 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 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 , 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 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 , - the working reinforcement comprising at least two working layers , 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 , comprising metallic reinforcers that form an angle at most equal to 15° with the circumferential direction (XX'), <EOS>