Numerical and Experimental Study on End Effect of Waste-Soil Samples under Uniaxial Compression

Abstract

In order to investigate the influence of end effect on the waste-soil sample strength under uniaxial compression, the influence law of end effect on the uniaxial compression strength is numerically simulated by the FLAC3D software, and the reliability of the numerical model is verified by comparing it with the test results. Based on the above model, the influence of end effect on the lateral displacement and stress state of waste-soil samples is simulated, and the formation mechanism of end effect under uniaxial compression is revealed. The results show that, when the friction coefficient increases from 0 to 0.4, the uniaxial compression strength and percentage of triaxial compression units first increase rapidly and then slowly and then finally remain invariant. With the increase of the friction coefficient, the lateral displacement of the sample is significantly reduced. On the end surface, the nearer to the edge one is, the greater the decrease is. The triaxial compression region on the axis section is triangular in distribution; with the increase of the friction coefficient, this region increases first rapidly and then slowly and then finally remains invariant. The end effect produces lateral compression stress by reducing the lateral displacement of the end surface of samples, and lateral compression stress causes the sample to enter the triaxial compression state. With the increase of the friction coefficient, the triaxial compression region increases gradually, and thus, the uniaxial compression strength of the entire sample increases.

Study on the influence of rock bridge angle on the size effect of rock uniaxial compression

“…(2) The relationship between UCS and rock size is obtained through linear regression. In existing research, scholars mainly study the effects of aspect ratio [11], water content [12], and strain rate [14] on UCS, but rarely establish mathematical models for UCS and rock size, and rarely consider the influence of rock bridge angle.…”

“…Fu et al [11] used granite and limestone for laboratory uniaxial compression test and found that the height-diameter ratio had a significant effect on UCS. Wang et al [12] explored from the perspective of moisture content and found that in the dry and saturated state, the UCS decreases slightly with increasing volume. Wang et al [13] used a large rigid test device to study the UCS from the perspective of aspect ratio, and found that as the aspect ratio increased, the UCS showed a trend of first decreasing and then increasing.…”

Deterioration mechanism of mechanical properties of phosphorite under different saturation duration

“…Water and rock sample volume have obvious influences on physical mechanics and deformation characteristics of sandstone. Through experiments, Wang et al (2019) concluded that: the elastic modulus and deformation modulus of sandstones are negatively correlated with the rock sample volume. The Poisson's ratio of dry sandstones increases with the increase of rock sample volume, while that of saturated sandstones increases first with the increase of rock sample volume and then becomes stable.…”

Influence of Water Saturation Time on Microstructure and Mechanical Properties of Jointed Limestone

“…The presence of water will promote the further development of the discontinuity, resulting in the fracture of the rock mass. In particular, due to the long-term action of water, the physical and mechanical properties of the rock in the aquifer will change, which has a great impact on the stability of the overlying rock and the surrounding rock of the roadway (Deng et al, 2017a;Duan and Ren, 2019;Wang et al, 2019). The mechanical model has played an important role in the study of jointed rock formation and rock mechanics.…”