Experimental study on the mechanical properties of water-rich mudstone under principal stress axis rotation

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiangdong Zhang ◽  
Xuefeng Zhang ◽  
Jiashun Liu ◽  
Kaixin Zhu ◽  
Yu Ren
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Principal Stress ◽  
Stress Axis ◽  
Axis Rotation

scholarly journals Experimental Study on Noncoaxial Characteristics of Saturated Remolded Loess

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xuemeng Jiang ◽  
Haoshuang Niu ◽  
Wenpeng Huang ◽  
Xuwen Shang ◽  
Deng Wang
Keyword(s):  
Principal Stress ◽  
Elastic Strain ◽  
Stress Amplitude ◽  
Intermediate Principal Stress ◽  
Deviatoric Stress ◽  
Stress Axis ◽  
Cycle Number ◽  
Stress Coefficient ◽  
Practical Engineering ◽  
Axis Rotation

In practical engineering, if the influence of noncoaxial stress and strain is not considered, part of soil deformation will be ignored, resulting in the structural design which is not safe enough. A series of undrained tests was performed on remolded loess specimens using a hollow cylinder apparatus to examine the coupling between principal stress magnitude and direction in these specimens. First, the elastic parameters of remolded loess were obtained, and these parameters were used as the basis for investigating the noncoaxiality of the soil body under principal stress axis rotation (PSAR). The effects of elastic strain, intermediate principal stress coefficient, and magnitude of the deviatoric stress on the noncoaxiality of remolded loess were also investigated. The results of these experiments show that remolded loess exhibits significant noncoaxial behavior during PSAR. The noncoaxiality angle of remolded loess cyclically fluctuates with increases in the principal stress angle. It was also observed that the noncoaxiality angle will be overestimated if the effects of elastic strain are overlooked. Reversals in the direction of PSAR cause dramatic changes in the noncoaxiality angle. Increases in the intermediate principal stress coefficient are accompanied by increases in the noncoaxiality angle, up to a certain degree; however, these changes do not affect the development of the noncoaxiality angle. In coupled rotational tests with a range of deviatoric stress amplitudes, it was observed that changes in the deviatoric stress amplitude will affect the development of the noncoaxiality angle; increases in the deviatoric stress amplitude cause the noncoaxiality angle versus principle stress angle plot to shift to the left gradually, thus accelerating the trends of the noncoaxiality angle. Increases in the cycle number also increase the noncoaxiality of remolded loess.

A Rock Mechanics Case History of Elliot Lake

1973 ◽  
Vol 10 (7) ◽  
pp. 1023-1058 ◽  
Author(s):  
D. F. Coates ◽  
H. U. Bielenstein ◽  
D. G. F. Hedley
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Principal Stress ◽  
Seismic Velocity ◽  
Stress Axis ◽  
Lake Area ◽  
History Of ◽  
Major Principal Stress ◽  
East West

The Elliot Lake area is characterized by Proterozoic sediments containing uranium-bearing conglomerates separated by quartzite beds 10 to 100 ft (3.0 to 30.5 m) thick. The geological structure consists of a broad syncline with an east–west axis plunging about 5 °W, cut by northwest trending faults, and with steeply dipping east–west extension joints. All the mines use a stope-and-pillar method of extraction with narrow rib pillars about 250 ft (76 m) long on dip and sill pillars on strike.After the Elliot Lake Laboratory was established, detailed studies were undertaken to evaluate the methods that were available for the determination of the mechanical properties of the rock mass and its state of stress before mining. Practical studies were then made on the pillars, roofs, and abutments.Testing techniques were improved for the rock substance and the rock mass; however, much remains to be done to be able to characterize adequately the mechanical properties of the rock mass. A novel random sampling approach produced a suite of specimens many of which included fractures, with a mean uniaxial strength that was surprisingly little lower than the mean of only the solid specimens. The dispersion of values in such a suite was, of course, quite large. Of the other tests used, Brazilian tests were found to be useful for quality control of stress determinations using a strain recovery technique.The use of borehole pressure cells, seismic velocity, and borehole penetrometers as techniques for the determination of the mechanical properties of the rock mass remains questionable.The tectonic history of the region was resolved; it provides an explanation for the existence of horizontal stresses greater than vertical stresses and for the major principal stress to be oriented parallel to the axis of the syncline. It was also shown that the major principal stress axis is essentially parallel to the strike of extension joint surfaces, even when the strike deviates from the predominant 090° azimuth direction.After considerable experience with mining in these geologic conditions, which probably are more uniform than in most metal mines, the determination of stable spans of stopes and breadths of pillars can be done very well by judgment. However, for examining new layouts relatively simple theoretical analyses, particularly for the determination of stable pillar sizes, were found to provide a rational and useful basis for extrapolation.The stresses determined in pillars and abutment zones and the deformations of the roofs corresponded fairly well to values predicted by analytical and model techniques. The increased stress in the abutment zones extended into the solid for a relatively limited distance, which, in this relatively hard rock, seems to be related substantially to the span of the adjacent stope. All field measurements were subject to dispersion. The electrolytic analogue, which takes into account the three-dimensional aspects of the geometry of the tabular orebodies, showed that irregular mining boundaries have a distinct contribution to the variance of the pillar stresses. The finite element method was found to be flexible and useful in studying specific questions, particularly related to novel mining plans.

scholarly journals Effects of principal stress axis rotation on cyclic deformation characteristics of rail track subgrade materials

2017 ◽  
Vol 57 (3) ◽  
pp. 423-438 ◽  
Author(s):  
Biyanvilage Dareeju ◽  
Chaminda Gallage ◽  
Tatsuya Ishikawa ◽  
Manicka Dhanasekar
Keyword(s):  
Principal Stress ◽  
Cyclic Deformation ◽  
Stress Axis ◽  
Deformation Characteristics ◽  
Rail Track ◽  
Axis Rotation

scholarly journals Effects of Principal Stress Axis Rotation on Unsaturated Rail Track Foundation Deterioration

2016 ◽  
Vol 143 ◽  
pp. 252-259 ◽  
Author(s):  
Chaminda Gallage ◽  
Biyanvilage Dareeju ◽  
Manika Dhanasekar ◽  
Tatsuya Ishikawa
Keyword(s):  
Principal Stress ◽  
Stress Axis ◽  
Rail Track ◽  
Axis Rotation
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