Solution is an essential character for salt rocks. Pervasion is a liquid movement through porous media under the actions of solute concentration gradients，pressure gradients，or the both. As the difference of solution characters for different mineral components in calcium thenardite，the solution and pervasion mutual actions can be found in the calcium thenardite rock salt body under the action of certain osmotic pressure. Thus the calcium thenardite becomes penetrable porous medium，holding the pervasion and mechanical characteristics that are called solution pervasion and mechanical characteristics，respectively. It is greatly affected by the solubility of sodium sulfate，and one of the components is calcium thenardite. Experiments illustrate that the permeability is the function of solution time and osmotic pressure of calcium thenardite salt rock. Meanwhile，the three-dimensional mechanical characteristics of calcium thenardite salt rock take great changes after a period of solution pervasion actions. The compression strength of calcium thenardite rock salt changes from 46.53 MPa to 11.42 MPa after 49 h solution pervasion with 2.0 MPa confining pressure. Accordingly，the elastic modulus changes from 43.700 MPa to 0.834 MPa. So，it can be concluded that solution pervasion has great effect on mechanical characteristics of calcium thenardite rock salt.

Based on the achievement of 3D strata fracturing situation measured by microseismic monitoring techniques and field strata movement investigation，the authors present the concept of“strata spatial structure”. According to mining borders condition of longwall，strata spatial structures are divided into four shapes as follows：(1) q-shaped spatial structure with center support(coal pillar)；(2) O-shaped type spatial structure without center support(coal pillar)；(3) S-shaped；and (4) C-shaped. They are described on how to use microseismic monitoring techniques to decide the developing progress of strata spatial structure，and on how to use drill hole pressure changing rules to judge the stability of coal pillar which is surrounded by four goafs(four sides are mined areas) and under strata spatial structure. According to the drill hole pressure monitoring results in sub-level caving face goaf，the forming progress of strata spatial structures without center support(coal pillar) is described. Based on field monitoring practice，the authors discuss the applying method of microseismic monitoring techniques and drill hole pressure monitoring to the research on strata spatial structure，and show the application of the viewpoint of strata spatial structure and its research methods to mining engineering.

Based on the triaxial test results in the core wall of Maopingxi earth-rock fill dam which is the part of the Three Gorges Project in China，the stress-strain relationship and mechanical properties of asphalt concrete are studied. From the test results，it is found that the stress-strain curve of asphalt concrete included two phases of strain-harding and strain-softing；and that the triaxial test curve was a hump curve，which consists of shear-dilatancy and shear-compression during the shear test. The failure criterion of asphalt concrete was not in good agree with the Mohr-Coulomb criterion. The envelope line of shear strength was nonlinearly changing and downward bending with the increasing of confining pressure. The Nanshui nonlinear model was adopted to describe the characteristics of the stress-strain relationship of the asphalt concrete and compared with the Duncan-Chang nonlinear model. The comparative results indicated that the Nanshui nonlinear model seemed better to describe the mechanical properties of the asphalt concrete.

The gravitation level style rock rheology test machine was developed by the authors. Its scale-up ratio is 120 and the error is less than 0.4%. Load may keep stable in any time(e.g. long-term) to meet the requirements of rock rheology test. The rheology properties and stress effects of creep moduli under creep conditions were experimentally studied by using specimens of red sandstone under step load with the gravitational style rock rheology test machine. The differences between axial and lateral creep properties and long-term strength of rock were specially observed and analyzed. The experimental result shows that the lateral stress threshold of the second creep stage is less than that of axial stress threshold. There is an obvious accelerated stage in the lateral creep course；and the accelerated stage in lateral creep course appears earlier than that in the axial creep course；but the third stage of the axial creep is not obvious and the rock specimen will be damaged as soon as the third stage appears. According to the experimental result，the long-term strength of rocks should be determined in terms of lateral stress threshold of second creep stage of the rock；so the determined long-term strength value is less 19%–35% than that determined in terms of axial stress threshold of the second creep stage of the rocks. There is an important directive meaning for this result to account for the creep stability in the geotechnical engineering fields.