The numerical tests of soil-rock mixture (S-RM) were performed based on the in-suit horizontal push-shear test (HPST) in order to clarify the meso-damage evolution of S-RM. The mechanical properties and the meso-damage evolution characteristics of S-RM were analyzed by using discrete element method. A quantitative evaluation method for evaluating the anisotropy of S-RM meso-cracks was proposed based on the Fourier series approximation method. The meso-damage stages of HPST of S-RM were divided based on the anisotropy evolution of meso-cracks in the process of deformation and destruction of S-RM. The formation mechanism of S-RM shear surface was analyzed by analyzing the growth and evolution of cracks in different meso-damage stages. Results showed that the anisotropy degree of meso-cracks increased with the increment of shear displacement, but it has no obvious change any more after the formation of principal crack. The dips of meso-cracks were mainly distributed in 0°-45° and 135°-180°. The generation of meso-cracks was mainly caused by the tensile stress between particles. The anisotropy degree of tensile meso-cracks was larger than that of shear meso-cracks. The connections of meso-cracks in the soil gave rise to the formation of multiple macro-cracks. The macro-cracks developed and formed a round-blocks principal crack because of the rotation of rock blocks. The S-RM slide along the principal cracked to form a round-blocks shear slide surface. The dip of slide surface was 34°, same as the dip of principal crack and the average dip of meso-cracks in the range of 0°-90°.
Han ZHANG,Xin-li HU,Shuang-shuang WU. Damage evolution of soil-rock mixture based on Fourier series approximations method. Journal of ZheJiang University (Engineering Science), 2019, 53(10): 1955-1965.
Tab.1Results of horizontal push-shear test of S-RM
Fig.4Typical limestone blocks with different grain sizes
Fig.5Cumulative grading curves of S-RM
Fig.6Simulation model of S-RM horizontal push-shear test
岩土体
dblock/mm
接触模型
Dp/mm
E/MPa
Ra
ρ/（kg·m?3）
Sn/MPa
Ss/MPa
Eb/MPa
Rb
f
块石
10~120
平行黏结
4
200
1.0
2 700
24
24
200
1.0
1.5
块石
5~10
线性接触
5~10
200
1.0
2 700
?
?
?
?
1.5
土体
?
接触黏结
2~5
10
1.0
2 500
0.17
0.17
?
?
0.5
Tab.2Meso-parameters of soil and rock blocks
Fig.7Position and dip angle of meso-cracks
Fig.8Distribution of meso-crack dip angle and fitted curve
Fig.9Evolution of horizontal force
Fig.10Slide surface of horizontal-push shear test
Fig.11Evolution of meso-cracks/energy disspation/porosity
Fig.12Evolution of meso-cracks anisotropy
Fig.13Anisotropy characteristics of meso-cracks in different stages
Fig.14Evolution of tensile meso-cracks and shear meso-cracks
Fig.15Evolution of meso-cracks in different dip angle ranges
Fig.16Evolution of meso-cracks average dip angle
Fig.17Development of macro-cracks
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