EXPERIMENTAL STUDY ON THE LATERAL FLOW SLIDE MECHANISM OF SATURATED LOESS MASS
-
摘要: 1920年海原Ms 8.5地震诱发了大量黄土液化型滑坡，多表现为低角度、长距离、流态化运动特征，甚至出现大范围近水平侧向扩展流滑现象，其特殊的成因机制颇受争议。为此，在对海原地震诱发的石碑塬滑坡遗迹详细勘查的基础上，借助DPRI-5大型环剪仪，进行饱和黄土稳态变形特性试验研究，探讨了固结压力、饱和度和剪切速率等因素对黄土稳态强度的影响规律。结果表明：黄土稳态强度受到固结压力、饱和度及加载速率等因素的影响。在不排水剪切条件下，固结压力越大，黄土孔压响应越慢，稳态强度越高；黄土的饱和度越高，黄土孔压响应越快，稳态强度越低；剪切速率对黄土强度具有一定弱化效应，当剪切速率＜0.1 mm/s时，剪切速率对强度影响较小；当剪切速率介于0.1~1 mm/s范围时，随着剪切速率的提高，稳态强度有不同程度的降低；当剪切速率＞1.0 mm/s时，随着剪切速率的增大，影响程度降低，稳态强度趋于恒定，总体上看来，饱和度越高，剪切速率对强度的弱化影响越明显。研究成果揭示了石碑塬饱和黄土层在低稳态强度下发生侧向流滑的致灾机理。Abstract: In 1920, the Haiyuan Ms 8.5 strong earthquake induced many loess liquefaction landslides, which were characterized by low angle, long distance, fluidization, and even phenomenon of large-scale horizontal lateral spreading flow slide happened, and the special formation mechanism is quite controversial. The Shibeiyuan landslide was one of the most typical examples of these landslides. Based on the detailed exploration of Shibeiyuan landslide remains, with the application of the DPRI-5 ring shear apparatus, the stability deformation characteristics of the liquefied saturation loess was studied and the influence laws of factors like consolidation pressure, saturability and shearing speed on the steady state strength of loess was discussed. The research indicates that the dynamic load level and its action mode affect considerably the stress-strain of loess and the developing law of pore water pressure; at the same void ratio, the steady state strength of saturated loess is not affected by early stress path, but related to consolidation pressure, saturation, loading rate and so on. The main conclusions are as follows:1Under the undrained shear condition, the higher the consolidation pressure gets, the slower the pore pressure response, and the higher the steady state strength gets2 The higher the saturation of loess gets, the faster the pore pressure response and the lower the steady state strength gets. 3 Shearing rate has a certain weakening effect on loess strength. When the shearing rate is within the scale of 0.1 mm/s, it poses little effect on the steady state strength; when the shearing rate ranges from 0.1 to 1 mm/s, the steady state strength reduces to various degree as the shearing rate increases; when the shearing rate is more than 1mm/s, the steady state strength tends to be constant because the increase of shearing rate would reduce the effects. In general, the higher the saturation degree is, the greater of the weakening effect of the shearing rate poses on the steady state strength. It reveals that steady deformation characteristics and the disaster-inducing mechanism of horizontal lateral flow slide of the Shibeiyuan saturated loess layer under low steady state strength.
-
图 1 石碑塬滑坡全貌
a—石碑塬滑坡全貌；b—液化形成的波浪起伏状堆积地貌
Figure 1. The picture of the Shibeiyuan landslide
图 2 石碑塬滑坡工程地质平面图
1—房屋；2—道路；3—沟道；4—剖面线；5—钻孔及编号；6—探井及编号；7—泉；8—地层界限；9—滑坡区边界; 10—滑源区边界；11—推测滑坡剪出口；12—被滑坡掩埋的沟道；13—马兰黄土；14—第四系全新统冲洪积层；15—滑坡堆积层
Figure 2. Engineering geological map of the Shibeiyuan landslide
图 3 石碑塬滑坡工程地质纵剖面图(Ⅱ-Ⅱ')
Figure 3. Engineering geological longitudinal section of the shibeiyuan landslide
图 4 不同正应力下环剪试验时程曲线
Figure 4. Time-history curves of the ring shear test under different normal stress
图 5 环剪试验的应力路径关系曲线
Figure 5. Stress path curves under different initial strains of the ring shear test
图 6 环剪试验的黄土峰值强度和稳态强度
Figure 6. Losses peak strength and steady state strength of the ring shear test
图 7 不同饱和度黄土环剪试验时程曲线
Figure 7. Time-history curves of the losses ring shear test under different saturabilities
图 8 不同饱和度黄土的孔压时程曲线
Figure 8. Time-history curves of losses pore pressure of different saturabilities
图 9 不同饱和度黄土的峰值强度和稳态强度
Figure 9. Losses peak strength and steady state strength under different saturabilities
表 1 试验黄土的基本物性指标
Table 1. The basic physical parameters of the test loess
取样深度/m 土的天然状态物性指标 塑性指数Ip 粒度组成/% 天然密度ρ/(g·cm-3) 含水率ω/% 孔隙比e0 粘粒＜0.005/mm 粉粒0.005~0.075/mm 砂粒0.075~2.0/mm 14.10 1.47 5.30 1.02 4.56 8.52 78.64 12.84 
下载: 导出CSV
-
[1] 袁丽侠.宁夏海原地震诱发黄土滑坡的形成机制研究-以西吉地区地震诱发黄土滑坡为例[D].西安: 西北大学, 2005.YUAN Lixia. The mechanism of loess landslide caused by earthquake in Haiyuan of Ninxia-taking the earthquake-induced loess landslide in Xiji as an example[D]. Xi'an: Northwestern University, 2005. (in Chinese with English abstract) [2] 陈永明, 石玉成.中国西北黄土地区地震滑坡基本特征[J].地震研究, 2006, 29(3):276~280. doi: 10.3969/j.issn.1000-0666.2006.03.012CHEN Yongming, SHI Yucheng. Basic characteristics of seismic landslides in loess area of northwest China[J] Journal of Seismological Research, 2006, 29(3):276~280. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-0666.2006.03.012 [3] 黄润秋, 裴向军, 张晓超, 等.黄土动参数与地震诱发黄土滑坡灾害机理专题研究[R].成都: 成都理工大学, 2014.HUANG Runqiu, PEI Xiangjun, ZHANG Xiaochao, et al. Special study on loess dynamic parameters and mechanism of loess landslides induced by earthquake[R]. Chengdu: Chengdu University of Technology, 2014. (in Chinese) [4] 白铭学, 张苏民.高烈度地震时黄土地层的液化移动[J].工程勘察, 1990, (6):1~5. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK000000551291BAI Mingxue, ZHANG Sumin. Liquefaction movement of loess strata in high intensity earthquake[J]. Geotechnical Investigation and Surveying, 1990, (6):1~5. (in Chinese with English abstract) http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK000000551291 [5] 王家鼎, 白铭学, 肖树芳.强震作用下低角度黄土斜坡滑移的复合机理研究[J].岩土工程学报, 2001, 23(4):445~449. doi: 10.3321/j.issn:1000-4548.2001.04.013WANG Jiading, BAI Mingxue, XIAO Shufang. A study on compound mechanism of earthquake-related sliding displacements on gently inclined loess slope[J]. Chinese Journal of Geotechnical Engineering, 2001, 23(4):445~449. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2001.04.013 [6] Zhang D X, Wang G H. Study of the 1920 Haiyuan earthquake-induced landslides in loess (China)[J]. Engineering Geology, 2007, 94(1/2):76~88. https://www.researchgate.net/publication/223359157_Study_of_the_1920_Haiyuan_earthquake-induced_landslides_in_loess_China [7] 王兰民, 张振中, 王峻, 等.随机地震荷载作用下黄土动本构关系的试验研究[J].西北地震学报, 1992, 14(4):61~68. http://d.old.wanfangdata.com.cn/Conference/140608WANG Lanmin, ZHANG Zhenzhong, WANG Jun, et al. Lab study of dynamic constitutive relationship of loess under random seismic loading[J]. Northwestern Seismological Journal, 1992, 14(4):61~68. (in Chinese with English abstract) http://d.old.wanfangdata.com.cn/Conference/140608 [8] 王兰民, 张振中, 王峻, 等.随机地震荷载作用下黄土动强度的试验方法[J].西北地震学报, 1991, 13(3):50~55. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK000003698205WANG Lanmin, ZHANG Zhenzhong, WANG Jun, et al. A test method of dynamic strength of loess under random seismic loading[J]. Northwestern Seismological Journal, 1991, 13(3):50~55. (in Chinese with English abstract) http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK000003698205 [9] 袁中夏, 王兰民, YASUDA S, 等.黄土液化机理和判别标准的再研究[J].地震工程与工程震动, 2004, 24(4):164~169. http://d.old.wanfangdata.com.cn/Periodical/dzgcygczd200404030YUAN Zhongxia, WANG Lanmin, Yasuda S, et al. Further study on mechanism and discrimination criterion of loess liquefaction[J]. Earthquake Engineering and Engineering Vibration, 2004, 24(4):164~169. (in Chinese with English abstract) http://d.old.wanfangdata.com.cn/Periodical/dzgcygczd200404030 [10] 杨振茂, 赵成刚, 王兰民, 等.饱和黄土的液化特性与稳态强度[J].岩石力学与工程学报, 2004, 23(22):3853~3860. doi: 10.3321/j.issn:1000-6915.2004.22.022YANG Zhenmao, ZHAO Chenggang, WANG Lanmin, et al. Liquefaction behaviors and steady state strength of saturated loess[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23(22):3853~3860. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-6915.2004.22.022 [11] 亓星, 许强, 彭大雷, 等.地下水诱发渐进后退式黄土滑坡成因机理研究——以甘肃黑方台灌溉型黄土滑坡为例[J].工程地质学报, 2017, 25(1):147~153. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gcdzxb201701020QI Xing, XU Qiang, PENG Dalei, et al. Mechanism of gradual retreat loess landslide caused by groundwater:A case study of the irrigation loess landslide in heifangtai, Gansu province[J]. Journal of Engineering Geology, 2017, 25(1):147~153. (in Chinese with English abstract) http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gcdzxb201701020 [12] 许强, 彭大雷, 李为乐, 等.溃散性滑坡成因机理初探[J].西南交通大学学报, 2016, 51(5):995~1004. doi: 10.3969/j.issn.0258-2724.2016.05.024XU Qiang, PENG Dalei, LI Weile, et al. Study on formation mechanism of diffuse failure landslide[J]. Journal of Southwest Jiaotong University, 2016, 51(5):995~1004. (in Chinese with English abstract) doi: 10.3969/j.issn.0258-2724.2016.05.024 [13] 张晓超, 黄润秋, 许模, 等.石碑塬滑坡黄土液化特征及其影响因素研究[J].岩土力学, 2014, 35(3):801~810. http://d.old.wanfangdata.com.cn/Periodical/ytlx201403031ZHANG Xiaochao, HUANG Runqiu, XU Mo, et al. Loess liquefaction characteristics and its influential factors of Shibeiyuan landslide[J]. Rock and Soil Mechanics, 2014, 35(3):801~810. (in Chinese with English abstract) http://d.old.wanfangdata.com.cn/Periodical/ytlx201403031 [14] 周永习, 张得煊, 罗春泳, 等.饱和黄土稳态强度特性的试验研究[J].岩土力学, 2010, 31(5):1486~1490. doi: 10.3969/j.issn.1000-7598.2010.05.023ZHOU Yongxi, ZHANG Dexuan, LUO Chunyong, et al. Experimental research on steady strength of saturated loess[J]. Rock and Soil Mechanics, 2010, 31(5):1486~1490. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2010.05.023 [15] Wang G H, Zhang D X, Gen F, et al. Pore-pressure generation and fluidization in a loess landslide triggered by the 1920 Haiyuan earthquake, China:A case study[J]. Engineering Geology, 2014, 174:36~45. doi: 10.1016/j.enggeo.2014.03.006 [16] 张帆宇.黄土的剪切行为和黄土滑坡[D].兰州: 兰州大学, 2011. http://cdmd.cnki.com.cn/Article/CDMD-10730-1012287701.htmZHANG Fanyu. Shear behavior of loess and loess landslides[D]. Lanzhou: Lanzhou University, 2011. (in Chinese with English abstract) http://cdmd.cnki.com.cn/Article/CDMD-10730-1012287701.htm [17] Sassa K, Fukuoka H, Wang G H, et al. Undrained dynamic-loading ring-shear apparatus and its application to landslide dynamics[J]. Landslides, 2004, 1(1):7~19. doi: 10.1007/s10346-003-0004-y [18] 王兰民, 石玉成, 刘旭, 等.黄土动力学[M].北京:地震出版社, 2003.WANG Lanmin, SHI Yucheng, LIU Xu, et al. Loess dynamics[M]. Beijing:Seismological Press, 2003. (in Chinese) -
下载:
计量
- 文章访问数: 208
- HTML全文浏览量: 65
- PDF下载量: 7
- 被引次数: 0
