Numerical analysis of the failure modes and stability of 3D slopes with interbreeding of soft and hard rocks
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摘要: 采用FLAC3D強度折減法，研究在巖層傾角、巖層與邊坡走向夾角變化時三維軟硬互層邊坡的穩定性狀況，并對其破壞模式進行辨識與歸納分析.結果表明：邊坡破壞模式的判別應綜合考慮巖層的傾角大小、巖層走向與邊坡走向的夾角大小及坡面上的剪出條件；當巖層與邊坡走向夾角β<90°時，隨著巖層傾角α的增大，邊坡的破壞模式變化趨勢為由蠕滑-壓致拉裂、塑流-拉裂、滑移-拉裂向滑移-彎曲、彎曲-拉裂轉變；當β>90°時，邊坡的破壞模式趨勢為塑流-拉裂、滑移-彎曲、彎曲-拉裂；邊坡穩定性系數隨走向夾角的增大先增加后減小，β=90°時最大，且α越大，穩定性系數峰值越大；順向時隨著巖層傾角的增大，邊坡的破壞模式變化趨勢為蠕滑-壓致拉裂、滑移-拉裂、滑移-彎曲、彎曲-拉裂，穩定性系數變化先減小后增大，存在一最不利巖層傾角，其對應的穩定性系數最小；反向坡的破壞模式變化趨勢為蠕滑-壓致拉裂和彎曲-拉裂，穩定性系數逐漸增加.Abstract: FLAC3D strength reduction method had been adopted to research on the stability of 3D slopes with interbedding of soft and hard rocks, when the dip angle of stratum and the angle between the strike direction of slope and stratum changed, and the failure modes were identified and analyzed. The results show that:to identify the failure modes of slopes, the angle of the rock stratum, the angle between the strike direction of slope and stratum and the cut off condition on the slope surface should be considered. When β (the intersecting angle between the strike direction of slope and that of strata)<90°, with the increase of α (the strata inclination), the failure modes change from creeping-pressure induced ripping, plastic flowing-ripping, sliding-ripping to sliding-bending and bending-ripping; when β>90°, the failure modes change from plastic flowing-ripping to sliding-bending, and then become bending-ripping. With the increase of the angle between the strike direction of slope and stratum, the slope stability coefficient increases at first and then decreases, it reaches the maximum when β=90°, and the greater the α is, the greater the coefficient peak is. For the dip slope, with the increase of the angle of stratum, the trend of failure modes is:creeping-pressure induced ripping, sliding-ripping, sliding-bending, and bending-ripping. The stability coefficient decreases first and then increases, and there is a most unfavorable angle of the stratum, the corresponding stability coefficient is the least. As for the anti-dip slope, the trend of failure modes is creeping-pressure induced ripping and bending-ripping, and the stability coefficient increases gradually.
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Key words:
- slopes /
- failure modes /
- stability /
- strength reduction method
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參考文獻
[1] Hoek E, Bray J W. Rock Slope Engineering. Washington DC:Institution of Mining&Metallurgy, 1977 [7] Hungr O, Evans S G. The occurrence and classification of massive rock slope failure. Felsbau, 2004, 22(2):16 [13] Dawson E M, Roth W H, Drescher A. Slope stability analysis by strength reduction. Géotechnique, 1999, 49(6):835 [16] Wei W B, Cheng Y M, Li L. Three-dimensional slope failure analysis by the strength reduction and limit equilibrium methods. Comput Geotech, 2009, 36(1-2):70 [19] Zienkiewicz O C, Humpheson C, Lewis R W. Associated and non-associated visco-plasticity and plasticity in soil mechanics. Géotechnique, 1975, 25(4):671 [20] Shen J Y, Karakus M. Three-dimensional numerical analysis for rock slope stability using shear strength reduction method. Can Geotech J, 2014, 51(2):164 [21] Kelesoglu M K. The evaluation of three-dimensional effects on slope stability by the strength reduction method. KSCE J Civ Eng, 2016, 20(1):229 -
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