The multi cleavage behaviour of rock mass is simulated by introducing the damage tensor which is determined from in situ data of joint sets,and the net stress is also introduced to account the mechanical effects of jointed rock mass.

In order to resolve the problem that the damage value under two level loads isn t equal to one, a cumulative nonlinear damage model and its math formula for fatigue are put forward by using the usual cumula- tive damage theories, avoiding the equivalent damage and considering the effect on material for load sequence, domanial latent damage and damage s uneven character.

For three kinds of materials, a family of equivalent damage curve was measured on various stress levels using toughness degradation fatigue tests by fixing a group of cyclic numbers.

The theory of equivalent damage was used to make conversion from the loading frequencies of old base course before overlay to that after overlay.

Based on the fatigue and rutting tests of asphalt mixture, the principle of equivalent damage and weather data of Shanxi Province, the paper calculates the fatigue and rut effective temperature of asphalt mixture for typical regions in Shanxi, and makes a reference for asphalt pavement design.

Considering the components whose service life accords with the Weibull distribution,the dependent failure of a parallel system comprising two components is analyzed to propose a method to transform the dependent failure into equivalent damage,thus analyzing further the dependent failure.