Papers by Author: Xiong Wei Li

Abstract: Experiment study on shallow gassy unsaturated sand under different confining pressure with GDS triaxial system's 4D stress path module is carried out. Different SWCC shapes under different confining pressures are analyzed. The results show that unsaturated sand's water retention capacity declines gradually with confining pressure infliction and accretion. Finally, shallow gassy sand's gas reservoir pressure characteristics with SWCC are analyzed and forecast, and it's conservative if the same thing is done based on SWCC without confining pressure.

Abstract: Considering the influence of atmosphere action, field test of swelling force on expansive soil is carried out in Nanning Guangxi. The test sustains a whole rain season. The testing results show that swelling force is closely linked to the process of rainfall. The phenomenon, that long drought turns the rain, induces a sudden change of swelling force. But the persistence of rainfall brings different influence on vertical and horizontal swelling force. The results of field test can provide reference to optimize the engineering design.

Abstract: Through the undrained dynamic triaxial experiment, the deformation characteristics of saturated soft clay under cyclic loading are investigated. The cyclic loading was simplified as sine wave. It is found that under different dynamic stress, the deformation patterns of specimen in this experiment can be divided into three kinds, such as dense compressed, tensile break-up and shear failure type. In the process of vibration, the deformation forms of samples can also be divided into three types by dynamic stress amplitude, such as stable, destructive and critical type. The dynamic stress amplitude corresponding to the critical type is called critical dynamic stress. With the dynamic elastic strain increasing gradually, the dynamic elastic modulus decreases and rigidity softening occurs. Furthermore, dynamic elastic modulus and dynamic elastic strain curve decrease while the cyclic number is increasing. Finally, to establish the equation of the relationship between dynamic elastic modulus and dynamic elastic strain, the factor of cycle number should be considered.