Study on triaxial meso-failure mechanism and damage variables of sandstone under chemical erosion;

The measurement of the high-cycle fatigue damage variable and the study of the damage evolutional law;

The variety of the stress-displacement curve area is selected to be the damage variable instead of the plastic strain energy per cycle.

A rational method for defining damage variables in one dimension;

In addition,six types of damage variables are defined.

Assuming the function of damage variables under the force of pile soil,and selecting ideal flexible model,it derives a set of formulas of the load-subsidence behavior of pile under axial load considering damage,and analyses the influence of soil around pile and pile base and the relation between pile loading capacity and the initial stiffness of loading.

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.

It also discusses the display of damage, the damage parameters and how to measure them with direct or indirect methods of mechanics or physics.

Then the feasibility of rock mass quality evaluation by fractal dimension is vertified, and a fractal method of rock damage parameter is advanced.

The maximum and critical plane of six-fatigue damage parameters under uni-axial, multi-axial proportional and multi-axial non-proportional were determined.

In the approach the fatigue damage parameter is defined as the plastic energy on the critical plane.

Based on analysing the damage parameter of coal and rock on the electromagnetic emission(EME),the forecasting principle of rock burst danger and the forecasting guideline of burst failure applying the EME method were expouned.