Formation of the Soil Arch and Load Transfer Mechanism of a Slope due to Excavation by 3D Particle Flow Code Simulation

Abstract

The soil arching effect is an important factor affecting the internal load transfer of excavation-induced slopes. Physical model tests are usually used for studying the soil arching effect. Although physical model tests can monitor local point loads to demonstrate changes in local stresses, changes in force chains inside slopes are rarely demonstrated by physical modelling, which restricts the understanding of load transfer. To explore overall changes in stresses in slopes from a more microscopic perspective, a numerical simulation of the slope under excavation was carried out. Using built-in code and fish function programming in PFC^3D, the slope model was developed. Monitoring areas were set up to monitor the changes in stresses and force chains during excavation. The simulation results show that excavation width affects the size of deformation area, and the deformation area expands as excavation width increases. Excavation causes load transfer and the formation of soil arching in the slope. A mechanism is proposed to explain the effect of excavation on soil arching formation and load transfer. The numerical simulation is important for revealing the load transfer of slopes during excavation, and the research results have practical value for the prevention and mitigation of landslides caused by excavation.

Keywords

PFC^3D / arching effect / excavation / sand / slope / engineering geology

References

[1] Chen C L, He K, Li T L. Research on the Mechanism of the Ancient Landslide Resurrection Triggered by Slope Toe Excavation. Northwestern Geology, 2014, 47(1): 255-260(in Chinese with English Abstract)

[2] Chen C, Indraratna B, McDowell G. et al.. Discrete Element Modelling of Lateral Displacement of a Granular Assembly under Cyclic Loading. Computers and Geotechnics, 2015, 69: 474-484.

[3] Chen M XElastic-Plastic Mechanics, 2007BeijingScience Press(in Chinese)

[4] Chen R P, Liu Q W, Wu H N. et al.. Effect of Particle Shape on the Development of 2D Soil Arching. Computers and Geotechnics, 2020, 125: 103662.

[5] Chen Y D, Yu Y, She Y X. Method for Determining Mesoscopic Parameters of Sand in Three-Dimensional Particle Flow Code Numerical Modeling. Chinese Journal of Geotechnical Engineering, 2013, 35(S2): 88-93(in Chinese with English Abstract)

[6] Chen Z DStudy on the Failure Mechanism and Optimization Design of Supporting for the Bedding Rock Slope with Weak Interlayer, 2017ChongqingChongqing Jiaotong University(in Chinese with English Abstract)

[7] Cheng Y M, Liu Z N, Song W D. et al.. Laboratory Test and Particle Flow Simulation of Silos Problem with Nonhomogeneous Materials. Journal of Geotechnical and Geoenvironmental Engineering, 2009, 135(11): 1754-1761.

[8] Cui P B, Zhu Y Q, Liu Y. et al.. Model Test and Particle Flow Numerical Simulation of Soil Arch Effect for Unsaturated Sandy Soil Tunnel. Rock and Soil Mechanics, 2021, 42(12): 3451-3466(in Chinese with English Abstract)

[9] Cundall P A, Strack O D L. Discussion: A Discrete Numerical Model for Granular Assemblies. Géotechnique, 1980, 30(3): 331-336.

[10] Duan Z, Tang H, Dang Q. et al.. Discrete Element Simulation of Landslide Induced by Slope Excavation. Journal of Chang’an University (Natural Science Edition), 2014, 34(5): 49-55(in Chinese with English Abstract)

[11] Fang K, An P J, Tang H M. et al.. Application of a Multi-Smartphone Measurement System in Slope Model Tests. Engineering Geology, 2021, 295: 106424.

[12] Fang K, Miao M H, Tang H M. et al.. Insights into the Deformation and Failure Characteristic of a Slope due to Excavation through Multi-Field Monitoring: A Model Test. Acta Geotechnica, 2023, 18(2): 1001-1024.

[13] Fang K, Tang H M, Li C D. et al.. Centrifuge Modelling of Landslides and Landslide Hazard Mitigation: A Review. Geoscience Frontiers, 2023, 14(1): 101493.

[14] Fang K, Tang H M, Su X X. et al.. Geometry and Maximum Width of a Stable Slope Considering the Arching Effect. Journal of Earth Science, 2020, 31(6): 1087-1096.

[15] Hadjigeorgiou J, Esmaieli K, Grenon M. Stability Analysis of Vertical Excavations in Hard Rock by Integrating a Fracture System into a PFC Model. Tunnelling and Underground Space Technology, 2009, 24(3): 296-308.

[16] Huang Z Y, Zhang Y X, Dong J. Determination of the lnfluence Scope of Opencast Mining in Bedding Slope Based on Arch Effect. Safety and Environmental Engineering, 2013, 20(4): 148-153(in Chinese with English Abstract)

[17] Khosravi M H, Pipatpongsa T, Takahashi A. et al.. Arch Action over an Excavated Pit on a Stable Scarp Investigated by Physical Model Tests. Soils and Foundations, 2011, 51(4): 723-735.

[18] Khosravi M, Tang L, Pipatpongsa T. et al.. Performance of Counterweight Balance on Stability of Undercut Slope Evaluated by Physical Modeling. International Journal of Geotechnical Engineering, 2012, 6(2): 193-205.

[19] Lai H JAnalysis of Formation-Evolution Mechanism and Bearing Characteristics of Soil Arching within a Piled Embankment, 2016WuhanHuazhong University of Science & Technology(in Chinese with English Abstract)

[20] Lai H J, Zheng J J, Zhang J. et al.. DEM Analysis of “Soil”-Arching within Geogrid-Reinforced and Unreinforced Pile-Supported Embankments. Computers and Geotechnics, 2014, 61: 13-23.

[21] Lai H J, Zheng J J, Zhang R J. et al.. Visualization of the Formation and Features of Soil Arching within a Piled Embankment by Discrete Element Method Simulation. Journal of Zhejiang University-Science A, 2016, 17(10): 803-817.

[22] Lai H J, Zheng J J, Zhang R J. et al.. Classification and Characteristics of Soil Arching Structures in Pile-Supported Embankments. Computers and Geotechnics, 2018, 98: 153-171.

[23] Li C D, Fu Z Y, Wang Y. et al.. Susceptibility of Reservoir-Induced Landslides and Strategies for Increasing the Slope Stability in the Three Gorges Reservoir Area: Zigui Basin as an Example. Engineering Geology, 2019, 261: 105279.

[24] Li G H, Wang Y T, Wang D. et al.. The Creep Behavior of Rock Shear Sepage under Different Seepage-Water Pressures. Mechanics of Time-Dependent Materials, 2023, 27: 351-365.

[25] Li N, Cheng Y M. Laboratory and 3-D Distinct Element Analysis of the Failure Mechanism of a Slope under External Surcharge. Natural Hazards and Earth System Sciences, 2015, 15(1): 35-43.

[26] Long Y Y, Tan Y. Soil Arching due to Leaking of Tunnel Buried in Water-Rich Sand. Tunnelling and Underground Space Technology, 2020, 95: 103158.

[27] Nadukuru S S, Michalowski R L. Arching in Distribution of Active Load on Retaining Walls. Journal of Geotechnical and Geoenvironmental Engineering, 2012, 138(5): 575-584.

[28] Pei X, Yuan G, Zhang X C. et al.. Study on the Mechanism of the Loess Landslide Triggered by Slope Toe Excavation—For the Example of the Landslide of Shajingyi. Mountain Research, 2017, 35(2): 195-202

[29] Pipatpongsa T, Fang K, Leelasukseree C. et al.. Stability Analysis of Laterally Confined Slope Lying on Inclined Bedding Plane. Landslides, 2022, 19(8): 1861-1879.

[30] Pipatpongsa T, Khosravi M H, Doncommul P. et al.. Excavation Problems in Mae Moh Lignite Open-Pit Mine of Thailand. Proc., Geo-Kanto, The Japanese Geotechnical Society Tochigi, 2009459-464

[31] Rui R, van Tol F, Xia X L. et al.. Evolution of Soil Arching; 2D DEM Simulations. Computers and Geotechnics, 2016, 73: 199-209.

[32] Shi C, Zhang Q, Wang S N. Numerical Simulation Technology and Application with Particle Flow Code (PFC5.0). Rock and Soil Mechanics, 2018, 39: 43(in Chinese)

[33] Tang H M, Wasowski J, Juang C H. Geohazards in the Three Gorges Reservoir Area, China—Lessons Learned from Decades of Research. Engineering Geology, 2019, 261: 105267.

[34] Terzaghi KTheoretical Soil Mechanics, 1943New YorkJohnwiley & Sons11-15.

[35] Xiang X C, Zhang H, Jiang G S. et al.. Soil Arching Effect of Anti-Slide Piles Based on Particle Flow Method. Chinese Journal of Geotechnical Engineering, 2011, 33(3): 386-391(in Chinese with English Abstract)

[36] Xu Z Y, Zhang L, Zhou S. Influence of Encasement Length and Geosynthetic Stiffness on the Performance of Stone Column: 3D DEM-FDM Coupled Numerical Investigation. Computers and Geotechnics, 2021, 132: 103993.

[37] Xue Q, Zhang M, Bi J. et al.. Exfoliation Erosion and Deformation Failure of Excavated Loess Slope. Northwestern Geology, 2019, 52(2): 158-166(in Chinese with English Abstract)

[38] Yang S, Li X Q. Study on Direct Shear Test Simulation of PFC3D Sand with Different Particle Shapes. Water Resources and Hydropower Engineering, 2019, 50(3): 139-144(in Chinese with English Abstract)

[39] Yin X T, Zheng Y N, Ma S K. Study of Inner Scale Ratio of Rock and Soil Material Based on Numerical Tests of Particle Flow Code. Rock and Soil Mechanics, 2011, 32(4): 1211-1215(in Chinese with English Abstract)

[40] Zhang L, Tang H M, Xiong C R. et al.. Movement Process Simulation of High-Speed Long-Distance Jiweishan Landslide with PFC 3D. Chinese Journal of Rock Mechanics and Engineering, 2012, 31(S1): 2601-2611(in Chinese with English Abstract)

[41] Zhang B C, Ning Y B, Tang H M. et al.. Study on the Evolutionary Process of Interbedded Anti-Inclined Slope Block-Flexure Toppling in the upper Yalong River. Bulletin of Engineering Geology and the Environment, 2023, 82: 240.

[42] Zhou B O, Wang H B, Zhao W F. et al.. Analysis of Relationship between Particle Mesoscopic and Macroscopic Mechanical Parameters of Cohesive Materials. Rock and Soil Mechanics, 2012, 33(10): 3171-3178(in Chinese with English Abstract)

[43] Zou Z X, Luo T, Tan Q W. et al.. Dynamic Determination of Landslide Stability and Thrust Force Considering Slip Zone Evolution. Natural Hazards, 2023, 118: 31-53.

[44] Zou Z X, Luo T, Zhang S. et al.. A Novel Method to Evaluate the Time-Dependent Stability of Reservoir Landslides: Exemplified by Outang Landslide in the Three Gorges Reservoir. Landslides, 2023, 20: 1731-1746.

RIGHTS & PERMISSIONS

China University of Geosciences (Wuhan) and Springer-Verlag GmbH Germany, Part of Springer Nature