Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

An investigation into the effects of block size on the mechanical behaviors of bimsoils using variable-angle shear experiments

  • 35 Accesses


Shear resistance is critical to the stability of bimsoils (block-in-matrix soils), although the shear mechanical behaviors of bimsoil have been widely studied, the effect of rock block size on the rock–soil interactions, block occlusion and the interlocking effect during shearing are still not well understood. This work aims to investigate the effect of block size on the macro–meso shear failure mechanism of bimsoils using a specially designed variable-angle shear testing. Compaction test with different hammer counts was used to prepare the bimsoil samples having different rock block proportions and sizes, to roughly ensure the same compactness of soil matrix. Macroscopic shear force–displacement analysis combined with the mesoscopic 3-D laser technique was used to reveal the internal shear failure mechanism. The results show that block size has obvious effect on the shear strength parameters and morphology of shear failure plane. The peak shear force increases with the increase of block size, and the occlusion and interlocking phenomena become severe for the sample with relatively large block size. An index of fractal dimension was used to establish the relationship between block size and shear strength parameters, it suggests that the fractal dimension of the fracture surface is large for the samples having larger block size, and the shear strength of bimsoil is strongly related to the morphology of fracture surface. The improvement of shear strength for bimsoil was the results of interactions between soil matrix and rock blocks and induced by the intrinsic shear fracture mechanism.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10


  1. Afifipour M, Moarefvand P (2014) Failure patterns of geomaterials with block-in-matrix texture: experimental and numerical evaluation. Arab J Geosci 7:2781–2792

  2. Alejano LR, Carranza-Torres C (2011) An empirical approach for estimating shear strength of decomposed granites in Galicia. Spain Eng Geol 120:91–102

  3. Barbero M, Bonini M, Borri-Brunetto M (2007) Numerical modelling of the mechanical behaviour of bimrock. In: Proceedings of the 11th international congress on rock mechanics, Lisbon, July 2007. Balkema, Rotterdam, pp 377–380

  4. Barbero M, Bonini M, Borri-Brunetto M (2008) Three-dimensional finite element simulations of compression tests on bimrock. In: Proceedings of the 12th international conference of international association for computer methods and advances in geomechanics (IACMAG), Goa, India, pp 631–637

  5. BSI (1990) BS 1377-1: Methods of test for soils for civil engineering purposes—part 1: general requirements and sample preparation. BSI, London

  6. Chang KT, Cheng MC (2014) Estimation of the shear strength of gravel deposits based on field investigated geological factors. Eng Geol 171:70–80

  7. Chu BL, Pan JM, Chang KH (1996) Field geotechnical engineering properties of gravel formations in western Taiwan. Sino-Geotechnics 55:47–58 (in Chinese)

  8. Chu BL, Jou YW, Weng MC (2010) A constitutive model for gravelly soils considering shear-induced volumetric deformation. Can Geotech J 38:662–673

  9. Clarke KC (1986) Direct fractal measurement of fracture surfaces. Comput. Geosci. No. 12, 713–717

  10. Coli N, Berry P, Boldini D (2011) In situ non-conventional shear tests for the mechanical characterisation of a bimrock. Int J Rock Mech Min 48:95–102

  11. Coli N, Berry P, Boldini D, Bruno R (2012) The contribution of geostatistics to the characterisation of some bimrock properties. Eng Geol 137:53–63

  12. Donaghe RT,Torrey VH (1979) Scalping and replacement effects on strength parameters of earth–rock mixtures. In: Proceedings of the european conference on soil mechanics and foundation engineering, vol 2, Brighton, pp 106–114

  13. Donaghe RT, Torrey VH (1994) Proposed new standard test method for laboratory compaction testing of soil-rock mixtures using standard effort. Geotech Test J 3:387–392

  14. Dupla JC, Pedro LS, Canou J et al (2007) Mechanical behavior of coarse-grained soils reference. Bull des Lab des Ponts et Chaussees 268–269:31–57

  15. Iannacchione AT (1997) Shear strength of saturated clays with floating rock particles. Ph.D. dissertation. University of Pittsburgh

  16. Kahraman S, Alber M, Fener M, Gunaydin O (2015) An assessment on the indirect determination of the volumetric block proportion of Misis fault breccia (Adana, Turkey). Bull Eng Geol Environ 74(3):899–907

  17. Kalender A, Sonmez H, Medley E, Tunusluoglu C, Kasapoglu KE (2014) An approach to predicting the overall strengths of unwelded bimrocks and bimsoils. Eng Geol 183:65–79

  18. Kokusho T, Hara T, Hiraoka R (2004) Undrained shear strength of granular soils with different particle gradations. J Geotech Geoenviron Eng 130(6):621–629

  19. Li X, Liao QL, He JM (2004) In-situ tests and a stochastic structural model of rock and soil aggregate in the three Gorges Reservoir area. China Int J Rock Mech Min Sci 41(3):702–707

  20. Lindquist ES (1994) The strength and deformation properties of melange. Ph.D.Thesis, Department of Civil Engineering, University of California. Berkeley

  21. Lindquist ES, Goodman RE (1994) The strength and deformation properties of a physical model mélange. In: Proceedings of the 1st North American Rock Mechanics Symposium, Austin, pp 843–850

  22. Mahdevari S, Maarefvand P (2017) Applying ultrasonic waves to evaluate the volumetric block proportion of bimrocks. Arab J Geosci 10(9):204

  23. Medley EW (2001) Orderly characterization of chaotic Franciscan Melanges. Felsbau Rock Soil Eng 19(4):20–33

  24. Medley E, Lindquist ES (1995) The engineering significance of the scale-indepen- dence of some Franciscan melanges in California, USA. In: Daemen J, Schultz R (eds) Proceedings of the 35th US rock mechanics symposium, Reno, Nevada. Balkema, Rotterdam, pp 907–914

  25. MWRPRC (Ministry of Water Resources of the People’s Republic of China) (1999) GB/T 50123-1999: Standard for soil test method. MWRPRC, Beijing

  26. Rücknagel J, Götze P, Hofmann B, Christen O (2013) The influence of soil gravel content on compaction behavior and pre-compression stress. Geoderma 209:226–232

  27. Sonmez H, Tuncay E, Gokceoglu C (2004) Models to predict the uniaxial compressive strength and the modulus of elasticity for Ankara Agglomerate. Int J Rock Mech Min Sci 41:717–729

  28. Sonmez H, Gokceoglu C, Medley E, Tuncay E, Nefeslioglu HA (2006) Estimating the uniaxial compressive strength of a volcanic bimrock. Int J Rock Mech Min Sci 43:554–561

  29. Vallejo LE (2001) Interpretation of the limits in shear strength in binary granular mixtures. Can Geotech J 38:1097–1104

  30. Vallejo LE, Mawby R (2000) Porosity influence on the shear strength of granular material–clay mixtures. Eng Geol 58:125–136

  31. Wang Y, Li X, Zhang B, Wu YF (2014) Meso-damage cracking characteristics analysis for rock and soil aggregate with CT test. Sci China Technol Sci 57(7):1361–1371

  32. Wang Y, Li X, Zheng B, Zhang B, Wang JB (2015) Real-time ultrasonic experiments and mechanical properties of soil and rock mixture during triaxial deformation. Géotech Lett 5(4):281–286

  33. Wang Y, Li X, Zheng B, He JM, Li SD (2016) Macro–meso failure mechanism of soil–rock mixture at medium strain rates. Géotech Lett 6:235–243

  34. Wang Y, Li CH, Wei XM (2017a) Investigation of the macro-meso failure mechanism for soil–rock mixture under splitting loading using real-time ultrasonic measurement and 3-D laser scanning. Eur J Environ Civ Eng. https://doi.org/10.1080/19648189.2017.1374882

  35. Wang Y, Li C, Hu Y, Xiao Y (2017b) Optimization of multiple seepage piping parameters to maximize the critical hydraulic gradient in bimsoils. Water 9(10):787

  36. Wang Y, Que JM, Wang C, Li CH (2018) Three-dimensional observations of meso-structural changes in bimsoil using X-ray computed tomography (CT) under triaxial compression. Constr Build Mater 190:773–786

  37. Xie HP (1996) Fractal-rock mechanics. Science Press, Beijing, pp 3–35 (in Chinese)

  38. Xie H, Wang JA, Stein E (1998) Direct fractal measurement and multifractal properties of fracture surfaces. Phys Lett A 242(1–2):41–50

  39. Xu WJ, Xu Q, Hu RL (2011) Study on the shear strength of soil–rock mixture by large scale direct shear test. Int J Rock Mech Min Sci 48(8):1235–1247

  40. Zhang S, Tang H, Zhan H, Lei G, Cheng H (2015) Investigation of scale effect of numerical unconfined compression strengths of virtual colluvial–deluvial soil–rock mixture. Int J Rock Mech Min Sci 77:208–219

  41. Zhang ZL, Xu WJ, Xia W, Zhang HY (2016) Large-scale in situ test for mechanical characterization of soil–rock mixture used in an embankment dam. Int J Rock Mech Min Sci 86:317–322

  42. Zhou HW, Xie H (2003) Direct estimation of the fractal dimentions of a fracture surface of rock. Surf Rev Lett 10(5):751–762

Download references


The authors would like to thank the editors and the anonymous reviewers for their helpful and constructive comments. The authors thank the Key Laboratory of Shale Gas and Geoengineering in the Institute of Geology and Geophysics, for providing the laser-scanning device. This study was supported by National key technologies Research & Development program (2018YFC0808402), the Key Laboratory of Geo-hazards Prevention and Geoenvironment Protection (Chengdu University of Technology (SKLGP2019K017), the Fundamental Research Funds for the Central Universities (FRF-TP-19-004B1), and the National key technologies Research & Development program (2017YFC0804609).

Author information

Correspondence to Y. Wang.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Wang, Y., Feng, W.K., Li, C.H. et al. An investigation into the effects of block size on the mechanical behaviors of bimsoils using variable-angle shear experiments. Environ Earth Sci 79, 69 (2020). https://doi.org/10.1007/s12665-020-8812-0

Download citation


  • Laboratory test
  • Bimsoil
  • Shear strength
  • Surface toughness
  • Failure mechanism
  • Address