不同角度基覆面上土石混合体变形试验研究及对滑坡演化的启示

doi:10.13745/j.esf.sf.2022.9.5

摘要/Abstract

摘要：

由于基覆面的角度会对土石混合体滑坡的变形破坏产生重要影响,研究土石混合体滑坡的基覆面角度作用规律对于全面评价土石混合体滑坡的稳定性具有重要意义,然而目前基覆面角度研究定量化不足。为了研究在不同角度基覆面情况下土石混合体的变形破坏,利用设计的大型推剪仪对不同角度基覆面情况下的土石混合体变形破坏开展试验研究。结果表明:随着基覆面角度的增加,剪切面与基覆面的夹角增大,剪切面与基覆面的距离也会增加。当基覆面角度为25°时,位于剪切破裂带的土石混合体整体运移程度最好,当基覆面角度为45°时,位于剪切破裂带的土石混合体破裂程度最严重,土石混合体的整体运移程度最差,滑裂带治理难度最大。随着基覆面角度的增加,最大剪应力先增大后减小,中间出现临界作用角度(为45°),此时土石混合体变形破坏过程中的最大剪应力达到最大,孔隙水压力变化值与土压力变化值达到峰值所需要时间最长。本研究阐明了不同角度基覆面上土石混合体的强度及变形特征,揭示基覆面角度对土石混合体强度及变形破坏的作用机理,并确定了土石混合体与基覆面作用的临界作用角度,为今后评价基于土石混合体基覆面角度控制作用的滑坡等地质灾害的稳定性提供了一定的理论依据。

关键词: 滑坡, 土石混合体, 基覆面, 大型推剪试验, 不同角度, 变形破坏

Abstract:

The slope angle of bedrock surface plays an important role in deformation and failure of the overlying rock-soil mixture (debris). Therefore, it is of great importance to quantify the effect of bedrock slope on the evolution of landslides in order to obtain a comprehensive evaluation of the mechanical behavior and stability of landslides; however, such quantitative studies are currently lacking. To address this gap we carried out an experimental study on deformation and failure of rock-soil mixture under different slope angles of the underlying bedrock using a home-built large size push-shear apparatus. The results show that with increasing slope angle the included angle between the shearing and bedrock surfaces increases, and so does the distance between the two surfaces. At 25° inclination the overall movement of the rock-soil mixture in the shear zone is most stable; whereas at 45° inclination occurs the most serious debris rupture in the shear zone while the overall movement of debris is most unstable, and the slip zone is most difficult to manage. With increasing slope angle, the maximum shear stress first increases and then starts to decrease at 45° inclination—at this point, the maximum shear stress reaches maximum in the deformation process, and the peaking time of pore-water/soil pressure changes (from their initial values) reach maximum as well. The results and parameters obtained in this study provide a reference basis for evaluating landslide stability and other geological hazards based on the determination of bedrock slope.

Key words: landslide, soil-rock mixture, bedrock surface, large-scale push-shear test, inclination angle, deformation and failure

中图分类号:

P694
TU43

孙永帅, 胡瑞林. 不同角度基覆面上土石混合体变形试验研究及对滑坡演化的启示[J]. 地学前缘, 2023, 30(3): 494-504.

SUN Yongshuai, HU Ruilin. Effect of bedrock slope angle on deformation and failure of overlying rock-soil mixture: Insight into the evolution of landslides[J]. Earth Science Frontiers, 2023, 30(3): 494-504.

图/表 10

表1 粉土的初始物理力学性质

Table 1 Physical and mechanical properties of silt material

孔隙比	含水率/%	最大干密度/ (g·cm^-3)	黏聚力/ kPa	内摩擦角/ (°)
0.59	22.3	1.71	20	27.8

图1 大型推剪试验示意图

Fig.1 Experimental setup for large-scale push-shear tests

图2 模型在各基覆面的试验初始状态和剪切破坏状态 (a)—25°初始状态;(b)—25°剪切破坏状态;(c)—35°初始状态;(d)—35°剪切破坏状态;(e)—45°初始状态;(f)—45°剪切破坏状态;(g)—55°初始状态;(h)—55°剪切破坏状态;(i)—65°初始状态;(j)—65°剪切破坏状态。

Fig.2 Initial and shear-deformation states of testing models under different slope angles

图3 基覆面与剪切面夹角随基覆面角度变化示意

Fig.3 Change of included angle (between the shearing and bedrock surfaces) with slope angle

图4 模型在各角度情况下剪应力-位移曲线

Fig.4 Shear stress vs. shear displacement curves under different slope angles

图5 最大剪应力在各基覆面角度情况下示意图

Fig.5 Effect of slope angle on maximum shear-stress

图6 不同基覆面角度情况下孔隙水压力变化值

Fig.6 Temporal profile of pore-water pressure change under different slope angles (a)—25°;(b)—35°;(c)—45°;(d)—55°;(e)—65°。

图7 不同基覆面角度情况下土压力变化值

Fig.7 Temporal profile of soil pressure change under different slope angles (a)—25°;(b)—35°;(c)—45°;(d)—55°;(e)—65°。

图8 各角度情况下孔隙水压力变化值达到峰值时间

Fig.8 Effect of slope angle on the peaking time of pore-water pressure change

图9 各角度情况下土压力变化值达到峰值时间

Fig.9 Effect of slope angle on the peaking time of soil pressure change

参考文献 45

[1]	MEDLEY E W. The engineering characterization of melanges and similar block-in-matrix rocks (bimrocks)[M]. Berkeley: University of California, 1994.
[2]	MEDLEY E W. Estimating block size distributions of melanges and similar block-in-matrix rocks (bimrocks)[C]// Proceedings of 5th North American Rock Mechanics Symposium. Toronto: University of Toronto Press, 2002: 509-606.
[3]	油新华. 土石混合体的随机结构模型及其应用研究[J]. 岩石力学与工程学报, 2002, 21(11): 1748.
[4]	油新华, 何刚, 李晓. 土石混合体的分类建议[J]. 工程地质学报, 2002, 10(增刊): 448-452.
[5]	LI X, LIAO Q L, HE J M. In-situ tests and a stochastic structural model of rock and soil aggregate in the Three Gorges Reservoir area, China[J]. International Journal of Rock Mechanics and Mining Sciences, 2004, 41: 702-707.
[6]	李晓, 廖秋林, 赫建明, 等. 土石混合体力学特性的原位试验研究[J]. 岩石力学与工程学报, 2007, 26(12): 2377-2384.
[7]	陈剑, 陈瑞琛, 崔之久. 高速远程滑坡的地貌学与沉积学研究进展[J]. 地学前缘, 2021, 28(4): 349-360. DOI
[8]	张永双, 刘筱怡, 吴瑞安, 等. 青藏高原东缘深切河谷区古滑坡:判识、特征、时代与演化[J]. 地学前缘, 2021, 28(2): 94-105. DOI
[9]	李高, 谭建民, 王世梅, 等. 滑坡对降雨响应的多指标监测及综合预警探析:以赣南罗坳滑坡为例[J]. 地学前缘, 2021, 28(6): 283-294. DOI
[10]	胡峰, 李志清, 孙凯, 等. 冻土石混合体、冰石混合物和冻土在压、拉作用下的破坏特征对比[J]. 岩石力学与工程学报, 2021, 40(增刊1): 2923-2934.
[11]	徐华, 周廷宇, 王歆宇, 等. 川藏铁路红层改良路基填料压缩试验与颗粒流模拟研究[J]. 岩土力学, 2021, 42(8): 2259-2268.
[12]	WANG Y H, LI J L, JIANG Q, et al. Study on spatial variation of shear mechanical properties of soil-rock mixture[J]. Periodica Polytechnica Civil Engineering, 2019, 63(4): 1080-1091.
[13]	张振平, 付晓东, 盛谦, 等. 基于含石量指标的土石混合体非线性破坏强度准则[J]. 岩石力学与工程学报, 2021, 40(8): 1672-1686.
[14]	江强强, 徐杨青, 王浩. 不同含石量条件下土石混合体剪切变形特征的试验研究[J]. 工程地质学报, 2020, 28(5): 951-958.
[15]	RUILIN H, XIAO L, YU W, et al. Research on engineering geomechanics and structural effect of soil-rock mixture[J]. Journal of Engineering Geology, 2020, 28(2): 255-281.
[16]	TANG J Y, XU D S, LIU H B. Effect of gravel content on shear behavior of sand-gravel mixture[J]. Rock and Soil Mechanics, 2018, 39(1): 93-102.
[17]	YANG Z P, YIAN X, LEI X D, et al. Particle discrete element numerical study on factors of shear strength characteristics for soil-rock mixture[J]. Journal of Engineering Geology, 2020, 28(1): 39-50.
[18]	ZHANG Y S, WU R A, GUO C B, et al. Research progress and prospect on reactivation of ancient landslides[J]. Advances in Earth Science, 2018, 33(7): 728-740. DOI
[19]	ZHENG B N, DING D Y, ZHANG D, et al. CT scanning and PFC modeling combined 3D method for gravel-bearing slip soil[J]. Journal of Engineering Geology, 2019, 27(3): 569-576.
[20]	XIA J G, HU R L, QI S W, et al. Large-scale triaxial shear testing of soilrock mixtures containing oversized particles[J]. Chinese Journal of Rock Mechanics and Engineering, 2017, 36(8): 2031-2039.
[21]	ZHONG Z L, TU Y L, HE X Y, et al. Research progress on physical index and strength characteristics of bimsoils[J]. Chinese Journal of Underground Space and Engineering, 2016, 12(4): 1135-1144.
[22]	HU F, LI Z Q, HU R L, et al. Research on the deformation characteristics of shear band of soil-rock mixture based on large scale direct shear test[J]. Chinese Journal of Rock Mechanics and Engineering, 2018, 37(3): 766-778.
[23]	刘顺青, 蔡国军, 周爱兆, 等. 不同含石率及基覆岩层倾角下土石混合体边坡稳定性分析[J]. 工程科学与技术, 2019, 51(4): 105-115.
[24]	夏加国, 胡瑞林, 祁生文, 等. 含超径颗粒土石混合体的大型三轴剪切试验研究[J]. 岩石力学与工程学报, 2017, 36(8): 2031-2039.
[25]	张敏超, 刘新荣, 王鹏, 等. 不同含石量下泥岩土石混合体剪切特性及细观破坏机制[J]. 土木与环境工程学报(中英文), 2019, 41(6): 17-26.
[26]	周中, 刘撞撞, 杨豪. 不同含石量下土石混合体重型击实验研究[J]. 江西理工大学学报, 2019, 40(5): 8-14.
[27]	严颖, 赵金凤, 季顺迎. 块石含量和空间分布对土石混合体抗剪强度影响的离散元分析[J]. 工程力学, 2017, 34(6): 146-156.
[28]	杨小彬, 侯鑫, 裴艳宇, 等. 大粒径石块分布对土石混合体稳定性的影响[J]. 科学技术与工程, 2020, 20(31): 12962-12967.
[29]	VALLEJO L E, LOBO-GUERRERO S, SEMINSKY L F, et al. Shear strength of sand-gravel mixtures: laboratory and theoretical analysis[C]// Geo-Congress 2014. Atlanta: American Society of Civil Engineers, 2014: 74-83.
[30]	LEE H K, PYO S H. Multi-level modeling of effective elastic behavior and progressive weakened interface in particulate composites[J]. Composites Science and Technology, 2008, 68(2): 387-397. DOI URL
[31]	VALLEJO L E, LOBO-GUERRERO S. The elastic moduli of clays with dispersed oversized particles[J]. Engineering Geology, 2005, 78(1/2): 163-171. DOI URL
[32]	丁小华, 周伟, 罗怀廷, 等. 基于透明土技术的土石混合体压缩变形试验研究[J]. 采矿与安全工程学报, 2021, 38(1): 157-164.
[33]	杜修力, 张佩, 金浏. 土石混合体宏观力学性能研究的细观等效分析方法[J]. 工程力学, 2017, 34(10): 44-52.
[34]	金磊, 曾亚武. 块石形状对土石混合体力学行为影响的颗粒流模拟[J]. 计算力学学报, 2016, 33(5): 753-759, 790.
[35]	ZENG Y W, JIN L, DU X, et al. Refined modeling and movement characteristics analyses of irregularly shaped particles[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2015, 39(4): 388-408. DOI URL
[36]	GRAZIANI A, ROSSINI C, ROTONDA T. Characterization and DEM modeling of shear zones at a large dam foundation[J]. International Journal of Geomechanics, 2012, 12(6): 648-664. DOI URL
[37]	KOZICKI J, TEJCHMAN J, MRÓZ Z. Effect of grain roughness on strength, volume changes, elastic and dissipated energies during quasi-static homogeneous triaxial compression using DEM[J]. Granular Matter, 2012, 14(4): 457-468. DOI URL
[38]	LI Y R. Effects of particle shape and size distribution on the shear strength behavior of composite soils[J]. Bulletin of Engineering Geology and the Environment, 2013, 72(3/4): 371-381. DOI URL
[39]	喻江武, 苟志龙, 雷瑜, 等. 基于傅立叶逆变换的土石混合体模型生成研究[J]. 水利水电技术, 2019, 50(4): 7-15.
[40]	金磊, 曾亚武, 叶阳, 等. 不规则颗粒及其集合体三维离散元建模方法的改进[J]. 岩土工程学报, 2017, 39(7): 1273-1281.
[41]	雷晓丹, 杨忠平, 翟航, 等. 土石混合体块石破碎影响因素的颗粒流数值研究[J]. 工程地质学报, 2020, 28(6): 1193-1204.
[42]	杜修力, 张佩, 金浏, 等. 基于分形理论的北京地区砂砾石地层细观建模[J]. 岩石力学与工程学报, 2017, 36(2): 437-445.
[43]	陶庆东, 何兆益, 贾颖. 土石混合体路基填料分形特性与压实破碎特征试验研究[J]. 中外公路, 2020, 40(2): 243-248.
[44]	蔡正银, 李小梅, 关云飞, 等. 堆石料的颗粒破碎规律研究[J]. 岩土工程学报, 2016, 38(5): 923-929.
[45]	陈剑, 王全才, 李波. 西藏樟木滑坡特征及成因研究[J]. 自然灾害学报, 2016, 25(2): 103-109.