Experimental and numerical studies on the instability of simple homogeneous sandy slopes under different infiltration scenarios
SONG Xianghua1，2，TAN Yong2，3，LU Ye4，LIU Junyan1，LIU Yan1，WEI Huazhou5，LAI Ke5，XU Ze6
(1. School of Civil Engineering and Architecture，University of Jinan，Jinan，Shandong 250022，China；2. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China；3. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；4. School of Mechanics and Engineering Sciences，Shanghai University，Shanghai 200444，China；5. Technical Innovation Center of Mine Geological Environmental Restoration Engineering in Southern Karst Area，Ministry of Natural Resources，Nanning，Guangxi 530028，China；
6. Water Resources Research Institute of Shandong Province，Jinan，Shandong 250014，China )
Abstract：In practice，many slope projects usually present complex infiltration boundaries due to functional requirements. In this paper，a series of physical experiments about rainfall slopes with different infiltration scenarios (rainfall covering slope crest only，slope surface only，and both slope crest and surface) were carried out. DIC image technology was used to capture the initial micro deformations and macroscopic overall asymptotic displacements during the slope failure. The contour maps of shear zones and contact force-chains were extracted，and the failure mechanism of high permeable soil slopes under different infiltration scenarios was revealed by the CFD-DEM numerical simulation. The results show that the rainfall covered slope crest only is easy to cause the failure of the slope toe first，then spread upward along the slope surface，and finally lead to the overall slip failure with the failure pattern of wide at the top and narrow at the toe. It had longer stability period，while its failure had characteristic of suddenness. When the rainfall covered slope surface only，plastic deformation was prone to occur first near the slope crown and slope toe. As two deformation areas continuously expanded and connected，it triggered the retrogressive failure with longer period. Its failure pattern presented narrow at the top，narrow at the bottom，and wide in the middle. When the slope covered by the full-area rainfall，overall failure was prone to triggered directly with characteristics of suddenness and linearity. Its failure pattern presented wide on the top，wide on the bottom，and wide in the middle. The scenario of rainfall covered slope crest only had the largest failure distance and failure depth，followed by the rainfall covered both slope crest and surface，while the scenario of rainfall covered slope surface only had the smallest failure distance and failure depth. The scenario of rainfall covered slope crest only was more dangerous than scenario of rainfall covered slope surface only due to the shorter failure period and sudden failure. In addition，the phenomenon of force-chain arch is prone to form at the back edge of the slip surface after the slope failure，indicating that the slope has the ability of self-stability.
[1] TIAN H，KONG Z. Influence of rainfall intensity and slope on the slope erosion of longling completely weathered granite[J]. Applied Sciences，2023，13(5295)：1–12.
[2] XU J，UEDA K，UZUOKA R. Evaluation of failure of slopes with shaking-induced cracks in response to rainfall[J]. Landslides，2021，19：119–136.
[3] LIU X，WANG Y. Analytical solutions for annual probability of slope failure induced by rainfall at a specific slope using bivariate distribution of rainfall intensity and duration[J]. Engineering Geology，2023，313 (106969)：1–15.
[4] TAN Y，JIANG W，LUO W，et al. Longitudinal sliding event during excavation of Feng-Qi Station of Hangzhou Metro Line 1：post-failure investigation[J]. Journal of Performance of Constructed Facilities，2018，32(4)：04018039.
[5] 张 强，郑艳妮，贾朝军，等. 复杂水库调度及降雨条件下堆积体滑坡离心试验研究[J]. 岩石力学与工程学报，2023，42(10)：2 427–2 440.(ZHANG Qiang，ZHENG Yanni，JIA Chaojun，et al. Centrifugal experimental study on accumulation body landslides under complex reservoir operation and rainfall conditions[J]. Chinese Journal of Rock Mechanics and Engineering，2023，42(10)：2 427–2 440.(in Chinese))
[6] 李江山，李 滨，殷跃平，等. 强降雨诱发作用下岩溶山体滑坡机制研究——以关岭滑坡为例[J]. 岩石力学与工程学报，2023，42(6)：1 497–1 507.(LI Jiangshan，LI Bin，YIN Yueping，et al. Mechanism of Karst landslide induced by heavy rainfall：A case study of Guanling Landslide[J]. Chinese Journal of Rock Mechanics and Engineering，2023，42(6)：1 497–1 507.(in Chinese))
[7] 宋宇飞，曹琰波，范 文，等. 基于贝叶斯方法的降雨诱发滑坡概率型预警模型研究[J]. 岩石力学与工程学报，2023，42(3)：558–574.(SONG Yufei，CAO Yanbo，FAN Wen，et al. Probabilistic early warning model for rainfall-induced landslide based on Bayesian approach[J]. Chinese Journal of Rock Mechanics and Engineering，2023，42(3)：558–574.(in Chinese))
[8] WANG G，SASSA K. Pore-pressure generation and movement of rainfall-induced landslides: effects of grain size and fine-particle content[J]. Engineering Geology，2003，69(1/2)：109–125.
[9] 詹良通，刘小川，泰 培，等. 降雨诱发粉土边坡失稳的离心模型试验及雨强–历时警戒曲线的验证[J]. 岩土工程学报，2014，36(10)：1 784–1 790.(ZHAN Liangtong，LIU Xiaochuan，TAI Pei，et al. Centrifuge modeling of rainfall-induced slope failure in silty soils and validation of intensity-duration curves[J]. Chinese Journal of Geotechnical Engineering，2014，36(10)：1 784–1 790.(in Chinese))
[10] 林鸿州，于玉贞，李广信，等. 降雨特性对土质边坡失稳的影响[J]. 岩石力学与工程学报，2009，28(1)：198–204.(LIN Hongzhou，YU Yuzhen，LI Guangxin，et al. Influence of rainfall characteristics on soil slope failure[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(1)：198–204.(in Chinese))
[11] 罗 强，朱江江，张瑞国，等. 砂土边坡稳定性土工离心模型试验[J]. 岩石力学与工程学报，2018，37(5)：1 252–1 259.(LUO Qiang，ZHU Jiangjiang，ZHANG Ruiguo，et al. Geotechnical centrifugal model test on sandy soil slope stability[J]. Chinese Journal of Rock Mechanics and Engineering，2018，37(5)：1 252–1 259.(in Chinese))
[12] 杜 强，周 健，李翠娜. 降雨对滑坡形态影响的宏细观分析[J]. 工程勘测，2016，44(3)：1–6.(DU Qiang，ZHOU Jian，LI Cuina. Macro-meso analysis of the influence of rainfall on landslide form[J]. Geotechnical Investigation and Surveying，2016，44(3)：1–6.(in Chinese))
[13] 张 硕，裴向军，黄润秋，等. 黄土填方边坡降雨入渗特征及变形破坏模式的模型试验[J]. 中国公路学报，2019，32(9)：32–41. (ZHANG Shuo，PEI Xiangjun，HUANG Runqiu，et al. Model test on seepage characteristics and deformation failure modes of loess fill slope under rainfall[J]. China Journal of Highway and Transport，2019，32(9)；32–41.(in Chinese))
[14] TOHARI A，NISHIGAKI M，KOMATSU M. Laboratory rainfall-induced slope failure with moisture content measurement[J]. Journal of Geotechnical and Geo-environmental Engineering，2007，133(5)：575–587.
[15] 包小华，廖志广，徐长杰，等. 不同渗流边界条件下粉砂边坡失稳模型试验研究[J]. 岩土力学，2019，40(10)：3 789–3 796.(BAO Xiaohua，LIAO Zhiguang，XU Changjie，et al. Model test study of the failure of silty sand slope under different seepage boundary conditions[J]. Rock and Soil Mechanics，2019，40(10)：3 789–3 796. (in Chinese)
[16] 陆 烨，孙汉清，李 航. 改进型DIC技术在静压桩模型试验中的应用[J]. 上海大学学报：自然科学版，2018，24(6)：993–1 001.(LU Ye，SUN Hanqing，LI Hang. Application of modified DIC technology in press-in pile model test[J]. Journal of Shanghai University：Natural Sciences，2018，24(06)：993–1 001.(in Chinese))
[17] 陆 烨，王校勇，孙汉清，等. 室内静压沉桩试验桩周土体全过程位移场分析[J]. 同济大学学报：自然科学版，2018，46(10)：1 366–1 373.(LU Ye，WANG Xiaoyong，SUN Hanqing，et al. Analysis on soil displacement field caused by press in process of pile model tests[J]. Journal of Tongji University：Natural Sciences，2018，46(10)：1 366–1 373.(in Chinese))
[18] 钱纪芸，张 嘎，张建民. 降雨条件下土坡变形机制的离心模型试验研究[J]. 岩土力学，2011，32(2)：398–402.(QIAN Jiyun，ZHANG Ga，ZHANG Jianmin. Centrifuge model tests for deformation mechanism of soil slope during rainfall[J]. Rock and Soil Mechanics，2011，32(2)：398–402.(in Chinese))
[19] WANG G，SASSA K. Pore-pressure generation and movement of rainfall-induced landslides：effects of grain size and fine-particle content[J]. Engineering Geology，2003，69(1/2)：109–125.
[20] WU L Z，HUANG R Q，XU Q，et al. Analysis of physical testing of rainfall-induced soil slope failures[J]. Environmental Earth Sciences，2015，73(12)：8 519–8 531.
[21] CHUEASAMAT A，HORI T，SAITO H，et al. Experimental tests of slope failure due to rainfalls using 1g physical slope models[J]. Soils and Foundations，2018，58(2)：290–305.
[22] 宋享桦，谭 勇，刘俊岩，等. 拉拔作用下锚杆复合土钉支护协同作用细观机制研究[J]. 岩石力学与工程学报，2019，38(3)：591–605. (SONG Xianghua，TAN Yong，LIU Junyan，et al. Micro-analyses on working mechanism of composite soil nail-anchor supporting wall[J]. Chinese Journal of Rock Mechanics and Engineering，2019，38(3)：591–605.(in Chinese))
2024, Vol. 43 
