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目前常用的岩石力学强度准则大多没考虑中间主应力的影响,如Mohr-Coulomb准则、Hoek-Brown强度准则等,但对强度来说,主应力又是一个比较重要的因素 (Prashant, 2004)。
最近,我们研究了如下的强度准则:
J2=α+βσ3
它具有如下的优势:
(1)考虑了中间主应力的影响,在σ1-σ3坐标系中是一个带,而不是一条线;如图1所示。
(2)在子午面上是抛物线,更加符合实际;
(3)在pi平面上只有3个角点,比Mohr-Coulomb和Hoek-Brown更光滑;
(4)与试验结果相比,比Mohr-Coulomb和Hoek-Brown具有更大的确定性系数;如图2所示。
在主应力空间中的图形如图3所示。
Figure 1 The relationship between σ1and σ3 given by Mohr-Coulomb criteria, Hoek-Brown criteria and the present criteria , The 95% confidence interval for the present model is represented by the blue band.
Figure 2 The coefficients of determination of the three models for the eight triaxial data: (1) Dunham Dolomite, (2) Solenhofen Limestone, (3) Mizuho Trachyte, (4) Shirahama Sandstone, (5) KTB Amphibolite, (6) Marble, (7) Westerly Granite and (8) Yuubari shale.
(a)
(b)
Figure 3 The present criterion in principal stress space and on π plane.
参考文献
Prashant, Amit, Penumadu, Dayakar, 2004. Effect of intermediate principal stress on overconsolidated kaolin clay. J. Geotech. Geoenviron. Eng. 130 (3), 284–292.
https://doi.org/10.1016/j.mechmat.2020.103721
https://www.researchgate.net/publication/347890278_A_strength_criterion_for_rocks
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