A STUDY ON DYNAMIC CHARACTERISTICS OF SANDSHALE ELUVIAL LATERITE AT KUNMING CHANGSHUI INTERNATIONAL AIRPORT
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摘要: 昆明长水国际机场残积红土既是区域内重要的土地资源，更是各类工程建设的建筑地基，由于裂化特性，在现代气候条件下，红土出现了严重的开裂变形，其工程性质不断恶化。文章针对昆明长水国际机场砂页岩残积红土开展了一系列固结不排水动三轴试验分析研究。变形试验结果表明：砂页岩残积红土在某一次循环动应力中存在屈服应变；在相同的应变水平下，动弹性模量随着固结围压的增大而增大；同时砂页岩残积红土的阻尼比在动应变小幅度的增加时会发生骤降，并随着动应变的增加逐渐趋平。同时通过动强度试验得出砂页岩残积红土破坏动强度随着固结围压的增大而增大，并得到砂页岩残积红土在固结比Kc=1时的动抗剪强度指标，即cd=25.182 kPa，φd=12.985°，将其与固结不排水的静三轴试验下得出的抗剪强度指标进行了对比与分析。红土在动力作用下的剪切破坏实质是其土体中的弱结合水大量丧失，导致其颗粒之间的粘结力降低，从而内部单元体产生了相对位移。该研究成果对红土系统深入研究及工程实践应用具有重大的指导意义。Abstract: The eluvial laterite of Kunming Changshui International Airport is not only an important land resources in the region, but also the construction foundation for a variety of engineering construction. Due to the cracking characteristics, the laterite is seriously cracked and deformed under the modern climatic conditions, and its engineering properties are deteriorating. A series of consolidated undrained dynamic triaxial tests were carried out on sandshale eluvial laterite at Kunming Changshui International Airport. The results of deformation tests show that the eluvial laterite of sandshale has yield strain in a cyclic dynamic stress; the dynamic elastic modulus would increase with the growing of the consolidation confining pressure at the same strain level; moreover, the damping ratio of the eluvial laterite in sandshale would decrease sharply when the dynamic strain increases slightly, and level off gradually with the growing of dynamic strain afterwards. The dynamic strength tests show that he dynamic failure strength of the eluvial laterite in sandshale would increase with the growing of consolidation confining pressure, and the dynamic shear strength index of the eluvial laterite in sandshale at consolidation ratio Kc=1 could is obtained (that is cd=25.182 kPa and φd=12.985°), which was compared and analyzed with the shear strength index obtained under the consolidated undrained static triaxial test. In fact, the shear failure of laterite under dynamic action is due to the loss of a large amount of weakly bound water in its soil, which leads to the reduction of the cohesive force between its particles, resulting in the relative displacement of the internal units. Combined with the features of the earthquake in Kunming, the obtained research results on the dynamic characteristics of the eluvial laterite in sandshale have great guiding significance for the in-depth study of the laterite system and engineering practice.
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图 1 试样不同围压下动应力-动应变曲线(固结比Kc=1)
Figure 1. The dynamic stress-dynamic strain curves of the samples under different confining pressure
图 2 红土试样在不同围压下1/Ed-εd关系曲线
Figure 2. 1/Ed-εd relation curves of the eluvial laterite samples under different confining pressure
图 3 红土试样在100 kPa围压下Ed-εd关系曲线
Figure 3. Ed-εd relation curves of the eluvial laterite samples under confining pressure of 100 kPa
图 4 试样参数a与围压σc的拟合直线
Figure 4. The fitting straight line of the sample parameter a and the confining pressure σc
图 5 试样参数b与围压σc的拟合直线
Figure 5. The fitting straight line of the sample parameter b and the confining pressure σc
图 6 红土试样不同围压下阻尼比-动应变的关系散点图
Figure 6. The relation scatter diagram of the damping ratio-dynamic strain of the laterite samples under different confining pressure
图 8 昆明长水国际机场砂页岩残积红土动抗剪强度包络线(Kc=1)
Figure 8. The dynamic shear strength envelope curves of the eluvial laterite in sandshale at Kunming Changshui International Airport when Kc=1
表 1 昆明长水国际机场砂页岩残积红土的基本物理力学性质指标
Table 1. The basic physical mechanical property indexes of the eluvial laterite in sandshale at Kunming Changshui Airport
基本试验指标 界限含水率 抗剪强度指标 粒度成分特征值 密度ρ/(g/cm3) 含水率ω/% 土粒比重Gs 孔隙比e 液限ωL/% 塑限ωp/% 塑性指数Ip/% 液性指数IL 粘聚力c/kPa 内摩擦角φ/(°) 粉粒 黏胶粒 胶粒 0.075~0.005 0.005~0.002 < 0.002 1.42 41 2.83 1.81 69 38 31 0.1 72.708 11.875 83 5 4 
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表 2 昆明长水国际机场砂页岩残积红土固结不排水动三轴试验方案
Table 2. Dynamic triaxial test scheme for the eluvial laterite in sandshale without drainage at Kunming Changshui Airport
试验类型 变形试验 强度试验 组数 一 二 三 四 五 六 七 八 九 试样编号 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 施加的固结围压/kPa 100 200 300 100 200 300 施加的动应力/kPa 分级施加(50~300) 110 115 125 160 180 200 220 240 260 设定的振动次数/次 每级振动7次 振动300次
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表 3 不同固结围压下参数a和b的值
Table 3. The values of parameter a and b in equation (1)
参数 围压/kPa 100 200 300 a 0.01477 0.00764 0.00427 b 0.03678 0.03457 0.0312
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[1] 周志彬, 符必昌, 牛志文.分散剂对砂页岩残积红土(ε2d)粒度组成影响研究[J].价值工程, 2017, 36(5):175~177. http://d.old.wanfangdata.com.cn/Periodical/jzgc201705068ZHOU Zhibin, FU Bichang, NIU Zhiwen. Effect of dispersant on particle size composition of sandy shale laterite (ε2d)[J]. Value Engineering, 2017, 36(5):175~177. (in Chinese with English abstract) http://d.old.wanfangdata.com.cn/Periodical/jzgc201705068 [2] 王飞, 符必昌, 李明和, 等.昆明长水国际机场砂页岩(ε2d)残积红土的粒度成分研究[J].江西科学, 2016, 34(1):95~101. http://d.old.wanfangdata.com.cn/Periodical/jxkx201601021WANG Fei, FU Bichang, LI Minghe, et al. Granulometric composition study of sand-shale eluvial laterit in Kunming Changshui international airport[J]. Jiangxi Science, 2016, 34(1):95~101. (in Chinese with English abstract) http://d.old.wanfangdata.com.cn/Periodical/jxkx201601021 [3] 李明和.昆明长水机场红土粒度成分方法研究[D].昆明: 昆明理工大学, 2015.LI Minghe. Study on the method of granularity of laterite in Kunming Changshui Airport[D]. Kunming: Kunming University of Science and Technology, 2015. (in Chinese) [4] 彭钰翔.云南省地震保险制度建设研究[D].昆明: 云南大学, 2014.PENG Yuxiang. Study on the construction of earthquake insurance system in Yunnan Province[D]. Kunming: Yunnan University, 2014. (in Chinese) [5] 徐鹏.双向循环荷载作用下红土的动强度特性试验研究[D].杨凌: 西北农林科技大学, 2017. http://cdmd.cnki.com.cn/Article/CDMD-10712-1017100765.htmXU Peng. Study on dynamic strength characteristics of laterite underbidirectional cyclic loads[D]. Yangling: Northwest A & F University, 2017. (in Chinese with English abstract) http://cdmd.cnki.com.cn/Article/CDMD-10712-1017100765.htm [6] 骆俊晖.海口红土动力特性研究[D].海口: 海南大学, 2012.LUO Junhui. Research on dynamic characteristics of Haikou red soil[D]. Haikou: Hainan University, 2012. (in Chinese with English abstract) [7] 杨桂通.土动力学[M].北京:中国建材工业出版社, 2000.YANG Guitong. Soil dynamics[M]. Beijing:China Building Materials Industry Press, 2000. (in Chinese) [8] 中华人民共和国水利部.土工试验规程(SL237~1999)[M].北京:中国水利水电出版社, 1999.Ministry of Water Resources of the PRC. Specification of soil test (SL237~1999)[M]. Beijing:China Water Power Press, 1999. (in Chinese) [9] 鲍陈阳, 余湘娟, 高志兵.云南粉土的动力特性试验研究[J].防灾减灾工程学报, 2006, 26(3):321~325. http://d.old.wanfangdata.com.cn/Periodical/dzxk200603015BAO Chenyang, YU Xiangjuan, GAO Zhibing. Laboratory study on dynamic properties of silty soil[J]. Journal of Disaster Prevention and Mitigation Engineering, 2006, 26(3):321~325. (in Chinese with English abstract) http://d.old.wanfangdata.com.cn/Periodical/dzxk200603015 [10] 王杰贤.动力地基与基础[M].北京:科学出版社, 2001.WANG Jiexian. Dynamic foundation and foundation[M]. Beijing:Science Press, 2001. (in Chinese) [11] 陈国兴, 刘雪珠.南京及邻近地区新近沉积土的动剪切模量和阻尼比的试验研究[J].岩石力学与工程学报, 2004, 23(8):1403~1410. doi: 10.3321/j.issn:1000-6915.2004.08.033CHEN Guoxing, LIU Xuezhu. Testing study on ratio of dynamic shear moduli and ratio of damping for recently deposited soils in Nanjing and its neighboring areas[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23(8):1403~1410. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-6915.2004.08.033 [12] 王艳丽, 胡勇.饱和砂土动力特性的动三轴试验研究[J].地下空间与工程学报, 2010, 6(2):295~299. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dxkj201002015WANG Yanli, HU Yong. Dynamic triaxial testing study on dynamic characteristics of saturated sands[J]. Chinese Journal of Underground Space and Engineering, 2010, 6(2):295~299. (in Chinese with English abstract) http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dxkj201002015 [13] 赖玉明.饱和砂土的动力特性研究综述[J].西部探矿工程, 2005, 17(10):80~82. doi: 10.3969/j.issn.1004-5716.2005.10.038LAI Yuming. Review of dynamic characteristics of saturated sand[J]. West-China Exploration Engineering, 2005, 17(10):80~82. (in Chinese) doi: 10.3969/j.issn.1004-5716.2005.10.038 [14] 丁伯阳, 张勇.杭州第四系软土动力特性试验与土结构性影响的探讨[J].岩土力学, 2012, 33(2):336~342. doi: 10.3969/j.issn.1000-7598.2012.02.003DING Boyang, ZHANG Yong. Discussion on dynamic test and characteristics of structural properties of quaternary soft clay in Hangzhou region[J]. Rock and Soil Mechanics, 2012, 33(2):336~342. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2012.02.003 [15] 雷华阳, 姜岩, 陆培毅, 等.交通荷载作用下结构性软土动应力-动应变关系试验研究[J].岩石力学与工程学报, 2008, 27(S1):3052~3057. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK200802676414LEI Huayang, JIANG Yan, LU Peiyi, et al. Experimental study of dynamic stress-strain relation of structural soft soil under traffic load[J]. Chinese Journal of Rock Mechanics and Engineering, 2008, 27(S1):3052~3057. (in Chinese with English abstract) http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK200802676414 [16] 申权, 李明俊, 蒋文明, 等.动三轴试验测试土阻尼的影响因素与不足[J].江西科学, 2013, 31(1):84~89. doi: 10.3969/j.issn.1001-3679.2013.01.022SHEN Quan, LI Mingjun, JIANG Wenming, et al. Influence factors of soil damping used by dynamic triaxial test and its deficiency[J]. Jiangxi Science, 2013, 31(1):84~89. (in Chinese with English abstract) doi: 10.3969/j.issn.1001-3679.2013.01.022 [17] SEED H B, IDRISS I M. Simplified procedure for evaluating soil liquefaction potential[J]. Journal of the Soil Mechanics and Foundations Division, 1971, 97(9):1249~1273. http://d.old.wanfangdata.com.cn/NSTLHY/NSTL_HYCC0210192185/ [18] 阳卫红, 刘伟平, 扶名福.南昌地区红土的动强度特性试验研究[J].煤田地质与勘探, 2015, 43(6):84~86. doi: 10.3969/j.issn.1001-1986.2015.06.017YANG Weihong, LIU Weiping, FU Mingfu. Experimental research on dynamic strength of laterite in Nanchang[J]. Coal Geology & Exploration, 2015, 43(6):84~86. (in Chinese with English abstract) doi: 10.3969/j.issn.1001-1986.2015.06.017 [19] 王亚勇. 《建筑抗震设计规范》(GB 50011-2001)的主要特点[J].工程抗震, 2002, (1):1~7. doi: 10.3969/j.issn.1002-8412.2002.01.001WANG Yayong. Major feature of code for seismic design of building (GB 50011-2001)[J]. Earthquake Resistant Engineering, 2002, (1):1~7. (in Chinese with English abstract) doi: 10.3969/j.issn.1002-8412.2002.01.001 [20] 刘保健, 谢定义.随机荷载下土动力特性测试分析法[M].北京:人民交通出版社, 2001.LIU Baojian, XIE Dingyi. Analysis and test method of soil dynamic characteristics under random load[M]. Beijing:China Communications Press, 2001. (in Chinese) [21] 杨桂通.土动力学[M].北京:中国建材工业出版社, 2000.YANG Guitong. Soil dynamics[M]. Beijing:China Building Materials Industry Press, 2000. (in Chinese) [22] 钟龙辉.轻亚粘土地震液化判定方法的分析[J].岩土工程学报, 1980, 2(3):113~122. doi: 10.3321/j.issn:1000-4548.1980.03.013ZHONG Longhui. Analysis for evaluating liquefaction of low plasticity clays (CL) during earthquake[J]. Chinese Journal of Geotechnical Engineering, 1980, 2(3):113~122. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.1980.03.013 [23] 黄英, 符必昌.红土化作用及红土的工程地质特性研究[J].岩土工程学报, 1998, 20(3):40~44. doi: 10.3321/j.issn:1000-4548.1998.03.011HUANG Ying, FU Bichang. Research on laterization and specific property of laterite in engineering geology[J]. Chinese Journal of Geotechnical Engineering, 1998, 20(3):40~44. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.1998.03.011 -
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