Strength Prediction Model for Cohesive Soil–Rock Mixture with Rock Content
Fault fracture zones, characterized by high weathering, low strength, and a high degree of fragmentation, are common adverse geological phenomena encountered in tunneling projects. This paper performed a series of large-scale triaxial compression tests on the cohesive soil–rock mixture (SRM) samples...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/15/2/843 |
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| Summary: | Fault fracture zones, characterized by high weathering, low strength, and a high degree of fragmentation, are common adverse geological phenomena encountered in tunneling projects. This paper performed a series of large-scale triaxial compression tests on the cohesive soil–rock mixture (SRM) samples with dimensions of 500 mm × 1000 mm to investigate the influence of rock content P<sub>BV</sub> (20, 40, and 60% by volume), rock orientation angle <i>α</i>, and confining pressure on their macro-mechanical properties. Furthermore, a triaxial numerical model, which takes into account P<sub>BV</sub> and α, was constructed by means of PFC<sup>3D</sup> to investigate the evolution of the mechanical properties of the cohesive SRM. The results indicated that (1) the influence of the <i>α</i> is significant at high confining pressures. For the sample with an <i>α</i> of 0°, shear failure was inhibited, and the rock blocks tended to break more easily, while the samples with an <i>α</i> of 30° and 60° exhibited fewer fragmentations. (2) P<sub>BV</sub> significantly affected the shear behaviors of the cohesive SRM. The peak deviatoric stress of the sample with an <i>α</i> of 0° was minimized at lower P<sub>BV</sub> (<20%), while both the deformation modulus and peak deviatoric stress were larger at high P<sub>BV</sub> (>60%). Based on these findings, an equation correlating shear strength and P<sub>BV</sub> was proposed under consistent <i>α</i> and matrix strength conditions. This equation effectively predicts the shear strength of the cohesive SRM with different P<sub>BV</sub> values. |
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| ISSN: | 2076-3417 |