The modified secant modulus formula derived from the hyperbolic stress-strain relation is presented in this paper. Based on this proposed formula an analysis was made for the earth dam located in Hubei province, At the same time, similar analysis was also carried out by using the tangent modulus formula derived by Duncan and Chang. The modified modulus formula described in this paper evade the difficulties and the testing work involved in determing the initial modulus of the stress-strain curve as required by the Duncan-Chang equation. The concept of pre-consolidation pressure for soil is employed to modify the formula of initial modulus appeared in Duncan’s equation when minor principal stress is very small. Comparison of the calculations based on these two formulas revealed that the final results obtained by Duncan’s formula were influenced by initial modulus significantly while that by modified secant formula is independent of the initial modulus, and moreover, the final results obtained by modified secant formula are in agreement with that from observations.

In this paper a new method of shearing test by means of rigid technique is proposed , On the weak interfaces of rock, the shearing characteristics and process of shearing stress and displacement can be determined. It is favorable to research the mechanism of failure and various ultimate strength.

It is necessary to consider the bearing capacity and displacement of the silt with 76~82% water content, when power transmission towers are contucted. Fall scale experiments have been carried out for the above reasons. The results of the experiments have shown that the large plate foundation method for the tower is the most efficient safety economic and easy to be constructed. The foundation is stable and the settlement is uniform.

A triaxial unloading experimental method fitting the process of stress changes in engineering practice such as underground openings or mine slope stability is proposed. The surplus strength with cleer for interpretation of data. It is found that through such a test there are unique features of deformation during simultaneous unloading of longitudinal and transverse stresses, which indicates that it would be necessary for mechanical properties of rock mass by using loading process coincident with the stress changes in geotechnical engineering.

A study of failure properties of granite specimens under compression, tension, shear conditions at different loading rates has been conducted. The tests, having loading rates from 10-1 to 108 kg/cm2/sec, were carried out on a fast loading equipment for rock mechanics teat. It has been found that the strength of the granite specimens increases with the increasing of loading rates. Based on this study and some results from field tests, a criterion of dynamic failure of granite is presented.

This paper has studied the effect of ratio between wavelength and diameter of hole on the stress distribution around hole during passage of a triangular stress pulse by using dynamic finite element code. The computations for seven different ratios between wavelength and diameter of hole have carried out. Besides the complete curve of variations of dynamic stress concentration factors with the ratios the changes of whole stress field around hole were obtained, particularly, the variations of values and distribution regions of radial and tangential tension stresses around hole. In addition, the effect of the length of pulse front (rise from zero to peak) was considered and the comparisons of the stress distributions around hole during that the peaks of two stress pulses of different wavelengths pass a hole with the corresponding static cases have been made.

To measure and to judge the method of explosive acceleration is presented in this paper. The law of attenuation of explosive acceleration and its value in effect of proportional relationship in earth direction and topography are discussed. By means of theoretical and practical methods, the author proposes an opinion to solve some difficult problem on the measuring of explosive acceleration in the field.

The design principles of a rock acoustic emission remotemeasuring, automatic control, and time-recording system developed for the research of the basic properties of rock mechanics and field monitoring and measurement of rock engineering projects are reported in this paper. The working principles and structures of the seven unites of the system have been described in detail. The results of monitoring and measurement accomplished by the system are also evaluated. Laboratory and field practices have demonstrated that the system possesses satisfactory application effects.

A new type of stress piezometer, RS stress gage, is presented in this paper. This new type of stress gage make use of piezoelectricity of piezocrystal to measure dynamic stress and read the magnitude directly. To avoid the bad matching of the gage and rock mass in situ, the shell of the gage is made of rock core from in situ. It has been proved that the new stress gage can work well during the measuring of the stress of blast wave in rock mass as long as it was made fine, calibrated accurately, and inserted carefully.

Rock and soil mechanics are strongly applied science. It is closely related to the technology of experiments for development. This paper briefly discusses the application of modern micro-computer for data recording and processing in rock and soil mechanics testing, the advantage, necessary condition and range for applicability in automatic testing control, fundamental method and mathematical model testing control and the problem of computer system selection.