土工布加筋粗颗粒土变形与强度特性试验研究
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摘要
对不同土工布加筋层数的粗颗粒土试样进行常规三轴固结排水剪切试验,探讨试样加筋层数(简称筋数n=0～3)对粗颗粒土变形、强度特性的影响。结果表明:筋数n每增加1,不同围压下试样破坏时的轴向应变增大0.91%～2.00%,土体韧性增强,筋材可抑制试样的侧向变形;不同围压下,平均筋数n每增加1,试样变形模量增大5 378 kPa。加筋能够增大相变时的体积应变;在p–q平面内,同一筋数n下的相变点和破坏点均可用直线拟合。粗颗粒土的强度指标总体随筋数的增加而增大。对线性指标c和非线性指标φ0、Δφ,其随试样筋数n的变化均可近似用直线表示;n每增加1,内摩擦角φ′增大1.75°。最后提出一个方便表述加筋量多少的指标—加筋疏密指数IR,并给出三轴试验获得IR的方法。整理发现试样黏聚力c及准黏聚力Δc(加筋土比素土黏聚力的提高量)与IR均可用直线拟合;IR每增加1 m–1,c和Δc分别提高9.1和13.5 kPa。利用该参数对三轴试验下砂土、黏土和粗颗粒土加筋对其强度提高的效果进行总结分析,加筋对不同土c提高量差异显著,IR每增加1 m–1,砂土、黏土和粗颗粒土c分别提高0.07、0.50和8.75 kPa。基于准黏聚力原理,建立c及Δc与IR的关系,可根据该公式直接估计土体加筋后的黏聚力或准黏聚力。
The influences of geotextile reinforcement layer number n on the deformation and strength properties of coarse-grained soil were investigated by using the consolidated-drained triaxial compression tests on the samples with different n(n=0～3). The experimental results showed that the axial strain at failure increases by 0.91%～2.00% under different confining pressures, with the increment of n of 1, indicating the improvement of toughness. The geotextile could inhibit the lateral deformation of soil samples. The deformation modulus increased averagely by5 378 kPa with the increment of n of 1 under different confining pressures. The reinforcement could increase the volumetric strain at phase transition. Both points at phase transition and at failure with the same n could be fitted by lines in p–q plane. The strength indexes increased with the increase of n generally. With respect to the linear index c and nonlinear indexes such as φ0 and Δφ, its relationship with n was approximately linear, and the internal friction angle increased by 1.75 degrees with the increment of n of 1. Finally, the index of reinforcement IR was put forward by considering the description of the quantity of reinforcement conveniently, and the method to obtain IR by triaxial shear test was given. It was found that the relationships between cohesion c, pseudo-cohesion Δc(cohesion increment of reinforced earth) and IR could be fitted by lines, and with the increment of IR of 1 m–1, c and Δc increased by 9.1 kPa and 13.5 kPa, respectively. Using this parameter IR, the effect of strength increase to sands, clay and coarse-grained soil under triaxial test was analyzed and summarized. There were significant differences on the cohesion increment among these soils, where the c for sands, clay and coarse-grained soil increased by 0.07, 0.50 and 8.75 kPa with the increment of IR of 1 m–1. Based on the pseudo-cohesion principle, the relationships between c, Δc and IR were established, which can be used to evaluate c andΔc of reinforced earth directly.
The influences of geotextile reinforcement layer number n on the deformation and strength properties of coarse-grained soil were investigated by using the consolidated-drained triaxial compression tests on the samples with different n(n=0～3). The experimental results showed that the axial strain at failure increases by 0.91%～2.00% under different confining pressures, with the increment of n of 1, indicating the improvement of toughness. The geotextile could inhibit the lateral deformation of soil samples. The deformation modulus increased averagely by5 378 kPa with the increment of n of 1 under different confining pressures. The reinforcement could increase the volumetric strain at phase transition. Both points at phase transition and at failure with the same n could be fitted by lines in p–q plane. The strength indexes increased with the increase of n generally. With respect to the linear index c and nonlinear indexes such as φ0 and Δφ, its relationship with n was approximately linear, and the internal friction angle increased by 1.75 degrees with the increment of n of 1. Finally, the index of reinforcement IR was put forward by considering the description of the quantity of reinforcement conveniently, and the method to obtain IR by triaxial shear test was given. It was found that the relationships between cohesion c, pseudo-cohesion Δc(cohesion increment of reinforced earth) and IR could be fitted by lines, and with the increment of IR of 1 m–1, c and Δc increased by 9.1 kPa and 13.5 kPa, respectively. Using this parameter IR, the effect of strength increase to sands, clay and coarse-grained soil under triaxial test was analyzed and summarized. There were significant differences on the cohesion increment among these soils, where the c for sands, clay and coarse-grained soil increased by 0.07, 0.50 and 8.75 kPa with the increment of IR of 1 m–1. Based on the pseudo-cohesion principle, the relationships between c, Δc and IR were established, which can be used to evaluate c andΔc of reinforced earth directly.
引文
[1]Pan Qiujing,Sun Zhibin,Yang Xiaoli.Deformation of reinforced expansive soil slope and its influence factors[J].Mining and Metallurgical Engineering,2013,33(3):1-4.[潘秋景,孙志彬,杨小礼.加筋膨胀土边坡变形及影响因素分析[J].矿冶工程,2013,33(3):1-4.]
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[4]Wang Jiaquan,Zhang Liangliang,Chen Yajing,et al.Mesoscopic analysis of reinforced sand triaxial test using PFC3D[J].Journal of Hydraulic Engineering,2017,48(4):426-434.[王家全,张亮亮,陈亚菁,等.土工格栅加筋砂土三轴试验离散元细观分析[J].水利学报,2017,48(4):426-434.]
[5]Jie Yuxin,Li Guangxin,Zheng Jiqin.A new method for analysis of texsol[J].Engineering Mechanics,1999,16(3):81-89.[介玉新,李广信,郑继勤.纤维加筋土计算的新方法[J].工程力学,1999,16(3):81-89.]
[6]Xu Shaoman,Hong Changhua.A non-linear analysis for soft cohesive subsoil under embankment reinforced by geotextile[J].Chinese Journal of Geotechnical Engineering,1999,21(4):438-443.[徐少曼,洪昌华.土工织物加筋堤坝软基的非线性分析[J].岩土工程学报,1999,21(4):438-443.]
[7]Meng Fanxiang,Xu Chao.Comparation and analyses of direct shear test and pull-out test of the interface between soils and geosynthetics[J].Hydrogeology and Engineering Geology,2009(6):80-84.[孟凡祥,徐超.筋土之间直剪试验与拉拔试验的对比分析[J].水文地质工程地质,2009(6):80-84.]
[8]Liu Feiyu,Wang Pan,Wang Jun,et al.Experimental research on reinforcement-soil interface stiffness and damping ratio under cyclic shearing[J].Rock and Soil Mechanics,2016,37(Supp 1):159-165.[刘飞禹,王攀,王军,等.筋-土界面循环剪切刚度和阻尼比的试验研究[J].岩土力学,2016,37(增刊1):159-165.]
[9]Yang Min,Li Ning,Liu Xinxing,et al.Experimental research on interface frictional behaviors of the geotextile-reinforced soil[J].Journal of Xi’an University of Technology,2016,32(1):46-51.[杨敏,李宁,刘新星,等.土工布加筋土界面摩擦特性试验研究[J].西安理工大学学报,2016,32(1):46-51.]
[10]Ding Wantao,Tan Xin.Study on reinforced expansive soils by triaxial tests[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(Supp 1):2367-2370.[丁万涛,谭新.加筋膨胀土的三轴试验研究[J].岩石力学与工程学报,2003,22(增刊1):2367-2370.]
[11]Wang Mingyuan,Yu Yanhua,Li Qiren.Consolidation and drain shear test for expansive soils reinforced with geogrids[J].Journal of Sichuan University(Engineering Science Edition),2010,42(2):64-68.[汪明元,于嫣华,李齐仁.土工格栅加筋膨胀土的固结排水剪特性[J].四川大学学报(工程科学版),2010,42(2):64-68.]
[12]Jiang Jianqing,Yang Guolin,Li Yun,et al.Strength and deformation characteristics of red-sandstone granular soil reinforced with gabion mesh[J].Chinese Journal of Geotechnical Engineering,2010,32(7):1079-1086.[蒋建清,杨果林,李昀,等.格宾网加筋红砂岩粗粒土的强度和变形特性[J].岩土工程学报,2010,32(7):1079-1086.]
[13]Shi Liguo,Zhang Mengxi,Cao Peng.Triaxial shear strength characteristics of lime-soil reinforced with polypropylene fiber inclusions[J].Rock and Soil Mechanics,2011,32(9):2721-2728.[施利国,张孟喜,曹鹏.聚丙烯纤维加筋灰土的三轴强度特性[J].岩土力学,2011,32(9):2721-2728.]
[14]Zhu Hailong,Xing Yichuan,Zhang Aijun,et al.Experimental investigation on shear strength of reinforced coarsegrained soil[J].Journal of China Institute of Water Resources and Hydropower Research,2013,11(1):41-47.[朱海龙,邢义川,张爱军,等.加筋粗粒土强度的试验研究[J].中国水利水电科学研究院,2013,11(1):41-47.]
[15]Shi Xiong,Zhang Jiasheng,Meng Fei,et al.Large-scale triaxial test of reinforced coarse-grained soils[J].Journal of Sichuan University(Engineering Science Edition),2014,46(2):52-58.[石熊,张家生,孟飞,等.加筋粗粒土大型三轴试验研究[J].四川大学学报(工程科学版),2014,46(2):52-58.]
[16]Su Lihai,Li Ning,Zhu Caihui.Triaxial creep tests on geotextile reinforced soil[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(6):1273-1280.[苏立海,李宁,朱才辉.土工布加筋土的三轴蠕变试验研究[J].岩石力学与工程学报,2016,35(6):1273-1280.]
[17]Zhu Jungao,Shi Jiangwei,Luo Xuehao,et al.Experimental study on stress-strain-strength behavior of sand with different densities[J].Chinese Journal of Geotechnical Engineering,2016,38(2):336-341.[朱俊高,史江伟,罗学浩,等.密度对砂土应力应变强度特性影响试验研究[J].岩土工程学报,2016,38(2):336-341.]
[18]郑颖人,孔亮.岩土塑性力学[M].北京:中国建筑工业出版社,2010.
[19]罗汀,姚仰平,侯伟.土的本构关系[M].北京:人民交通出版社,2010.
[20]刘宗耀,杨灿文,王正宏,等.土工合成材料工程应用手册[M].北京:中国建筑工业出版社,2000.
[21]Huang Xianzhi,Bai Xiaohong.Study of shear strength characteristics of geobelt reinforced crushed gravel soil[J].Rock and Soil Mechanics,2005,26(9):1464-1468.[黄仙枝,白晓红.土工带加筋碎石土的抗剪强度特性研究[J].岩土力学,2005,26(9):1464-1468.]
[22]Bao Huafu,Zhou Yitang,Zhao Chuan,et al.Study on georid reinforced stone[J].Chinese Journal of Geotechnical Engineering,1999,21(2):217-221.[保华富,周亦唐,赵川,等.聚合物土工格栅加筋碎石土试验研究[J].岩土工程学报,1999,21(2):217-221.]
[23]Shi Xiong,Zhang Jiasheng,Peng Zhuang,et al.Experimental research on strength-deformation characteristics of reinforced coarse-grained soil[J].Mining and Metallurgical Engineering,2014,34(4):1-5.[石熊,张家生,彭状,等.加筋粗粒土强度变形特性试验研究[J].矿冶工程,2014,34(4):1-5.]
[24]Yuan Xueqi,Tan Songlin.Triaxial experiment study on Wushan reinforced soil[J].Northwestern Geology,2002,35(1):52-55.[袁雪琪,谭松林.巫山加筋土的三轴试验研究[J].西北地质,2002,35(1):52-55.]
[25]Han Zhixing,Liu Degui,Jiang Bing.Study on the geogrid reinforced clays consolidated undrained triaxial test[J].Journal of Southwest University of Science and Technology,2008,23(4):25-28.[韩志型,刘德贵,姜兵.加筋层数对土工格栅加筋粘土土体变形及强度的影响[J].西南科技大学学报,2008,23(4):25-28.]
[26]Du Yunxing,Shang ShouPing,Zhou Fen.Experimental study of clay reinforced by CFRP material[J].Journal of Xiangtan Mining Institute,2004,19(1):20-23.[杜运兴,尚守平,周芬.CFRP材料加筋粘土的试验研究[J].湘潭矿业学院院报,2004,19(1):20-23.]
[27]Nouri S,Nechnech A,Lamri B,et al.Triaxial test of drained sand reinforced with plastic layers[J].Arabian Journal of Geosciences,2016,9(1):53.
[28]Khedkar M S,Mandal J N.Behaviour of cellular reinforced sand under triaxial loading conditions[J].Geotechnical and Geological Engineering,2009,27(5):645-658.
[2]Yu Zehong,Zhang Qisen.Finite element analysis for mechanism of geonets-soil interaction[J].Chinese Journal of Geotechnical Engineering,1997,19(3):76-82.[喻泽红,张起森.土工网与土相互作用机理的有限元分析[J].岩土工程学报,1997,19(3):76-82.]
[3]Miao Chenxi,Zheng Junjie,Cui Lan,et al.Study of the macro-meso correlation of geogrid-soil interface and assessment method of reinforced performance[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(Supp 1):3249-3258.[苗晨曦,郑俊杰,崔岚,等.格栅-砂土界面宏细观关联性与加筋性能评价方法研究[J].岩石力学与工程学报,2016,35(增刊1):3249-3258.]
[4]Wang Jiaquan,Zhang Liangliang,Chen Yajing,et al.Mesoscopic analysis of reinforced sand triaxial test using PFC3D[J].Journal of Hydraulic Engineering,2017,48(4):426-434.[王家全,张亮亮,陈亚菁,等.土工格栅加筋砂土三轴试验离散元细观分析[J].水利学报,2017,48(4):426-434.]
[5]Jie Yuxin,Li Guangxin,Zheng Jiqin.A new method for analysis of texsol[J].Engineering Mechanics,1999,16(3):81-89.[介玉新,李广信,郑继勤.纤维加筋土计算的新方法[J].工程力学,1999,16(3):81-89.]
[6]Xu Shaoman,Hong Changhua.A non-linear analysis for soft cohesive subsoil under embankment reinforced by geotextile[J].Chinese Journal of Geotechnical Engineering,1999,21(4):438-443.[徐少曼,洪昌华.土工织物加筋堤坝软基的非线性分析[J].岩土工程学报,1999,21(4):438-443.]
[7]Meng Fanxiang,Xu Chao.Comparation and analyses of direct shear test and pull-out test of the interface between soils and geosynthetics[J].Hydrogeology and Engineering Geology,2009(6):80-84.[孟凡祥,徐超.筋土之间直剪试验与拉拔试验的对比分析[J].水文地质工程地质,2009(6):80-84.]
[8]Liu Feiyu,Wang Pan,Wang Jun,et al.Experimental research on reinforcement-soil interface stiffness and damping ratio under cyclic shearing[J].Rock and Soil Mechanics,2016,37(Supp 1):159-165.[刘飞禹,王攀,王军,等.筋-土界面循环剪切刚度和阻尼比的试验研究[J].岩土力学,2016,37(增刊1):159-165.]
[9]Yang Min,Li Ning,Liu Xinxing,et al.Experimental research on interface frictional behaviors of the geotextile-reinforced soil[J].Journal of Xi’an University of Technology,2016,32(1):46-51.[杨敏,李宁,刘新星,等.土工布加筋土界面摩擦特性试验研究[J].西安理工大学学报,2016,32(1):46-51.]
[10]Ding Wantao,Tan Xin.Study on reinforced expansive soils by triaxial tests[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(Supp 1):2367-2370.[丁万涛,谭新.加筋膨胀土的三轴试验研究[J].岩石力学与工程学报,2003,22(增刊1):2367-2370.]
[11]Wang Mingyuan,Yu Yanhua,Li Qiren.Consolidation and drain shear test for expansive soils reinforced with geogrids[J].Journal of Sichuan University(Engineering Science Edition),2010,42(2):64-68.[汪明元,于嫣华,李齐仁.土工格栅加筋膨胀土的固结排水剪特性[J].四川大学学报(工程科学版),2010,42(2):64-68.]
[12]Jiang Jianqing,Yang Guolin,Li Yun,et al.Strength and deformation characteristics of red-sandstone granular soil reinforced with gabion mesh[J].Chinese Journal of Geotechnical Engineering,2010,32(7):1079-1086.[蒋建清,杨果林,李昀,等.格宾网加筋红砂岩粗粒土的强度和变形特性[J].岩土工程学报,2010,32(7):1079-1086.]
[13]Shi Liguo,Zhang Mengxi,Cao Peng.Triaxial shear strength characteristics of lime-soil reinforced with polypropylene fiber inclusions[J].Rock and Soil Mechanics,2011,32(9):2721-2728.[施利国,张孟喜,曹鹏.聚丙烯纤维加筋灰土的三轴强度特性[J].岩土力学,2011,32(9):2721-2728.]
[14]Zhu Hailong,Xing Yichuan,Zhang Aijun,et al.Experimental investigation on shear strength of reinforced coarsegrained soil[J].Journal of China Institute of Water Resources and Hydropower Research,2013,11(1):41-47.[朱海龙,邢义川,张爱军,等.加筋粗粒土强度的试验研究[J].中国水利水电科学研究院,2013,11(1):41-47.]
[15]Shi Xiong,Zhang Jiasheng,Meng Fei,et al.Large-scale triaxial test of reinforced coarse-grained soils[J].Journal of Sichuan University(Engineering Science Edition),2014,46(2):52-58.[石熊,张家生,孟飞,等.加筋粗粒土大型三轴试验研究[J].四川大学学报(工程科学版),2014,46(2):52-58.]
[16]Su Lihai,Li Ning,Zhu Caihui.Triaxial creep tests on geotextile reinforced soil[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(6):1273-1280.[苏立海,李宁,朱才辉.土工布加筋土的三轴蠕变试验研究[J].岩石力学与工程学报,2016,35(6):1273-1280.]
[17]Zhu Jungao,Shi Jiangwei,Luo Xuehao,et al.Experimental study on stress-strain-strength behavior of sand with different densities[J].Chinese Journal of Geotechnical Engineering,2016,38(2):336-341.[朱俊高,史江伟,罗学浩,等.密度对砂土应力应变强度特性影响试验研究[J].岩土工程学报,2016,38(2):336-341.]
[18]郑颖人,孔亮.岩土塑性力学[M].北京:中国建筑工业出版社,2010.
[19]罗汀,姚仰平,侯伟.土的本构关系[M].北京:人民交通出版社,2010.
[20]刘宗耀,杨灿文,王正宏,等.土工合成材料工程应用手册[M].北京:中国建筑工业出版社,2000.
[21]Huang Xianzhi,Bai Xiaohong.Study of shear strength characteristics of geobelt reinforced crushed gravel soil[J].Rock and Soil Mechanics,2005,26(9):1464-1468.[黄仙枝,白晓红.土工带加筋碎石土的抗剪强度特性研究[J].岩土力学,2005,26(9):1464-1468.]
[22]Bao Huafu,Zhou Yitang,Zhao Chuan,et al.Study on georid reinforced stone[J].Chinese Journal of Geotechnical Engineering,1999,21(2):217-221.[保华富,周亦唐,赵川,等.聚合物土工格栅加筋碎石土试验研究[J].岩土工程学报,1999,21(2):217-221.]
[23]Shi Xiong,Zhang Jiasheng,Peng Zhuang,et al.Experimental research on strength-deformation characteristics of reinforced coarse-grained soil[J].Mining and Metallurgical Engineering,2014,34(4):1-5.[石熊,张家生,彭状,等.加筋粗粒土强度变形特性试验研究[J].矿冶工程,2014,34(4):1-5.]
[24]Yuan Xueqi,Tan Songlin.Triaxial experiment study on Wushan reinforced soil[J].Northwestern Geology,2002,35(1):52-55.[袁雪琪,谭松林.巫山加筋土的三轴试验研究[J].西北地质,2002,35(1):52-55.]
[25]Han Zhixing,Liu Degui,Jiang Bing.Study on the geogrid reinforced clays consolidated undrained triaxial test[J].Journal of Southwest University of Science and Technology,2008,23(4):25-28.[韩志型,刘德贵,姜兵.加筋层数对土工格栅加筋粘土土体变形及强度的影响[J].西南科技大学学报,2008,23(4):25-28.]
[26]Du Yunxing,Shang ShouPing,Zhou Fen.Experimental study of clay reinforced by CFRP material[J].Journal of Xiangtan Mining Institute,2004,19(1):20-23.[杜运兴,尚守平,周芬.CFRP材料加筋粘土的试验研究[J].湘潭矿业学院院报,2004,19(1):20-23.]
[27]Nouri S,Nechnech A,Lamri B,et al.Triaxial test of drained sand reinforced with plastic layers[J].Arabian Journal of Geosciences,2016,9(1):53.
[28]Khedkar M S,Mandal J N.Behaviour of cellular reinforced sand under triaxial loading conditions[J].Geotechnical and Geological Engineering,2009,27(5):645-658.