冻融循环条件下宝鸡地区水泥改良黄土力学特性研究
|
摘要
为研究水泥改良黄土在冻融循环作用下的力学特性,依托宝兰铁路项目的黄土路基改良工程,通过对原状黄土、重塑黄土和不同水泥配合比的水泥改良黄土进行室内冻融循环力学试验,研究了有限次冻融循环后试样的无约束抗压强度、抗剪强度及压缩变形变化规律和内在机理。结果表明:改良黄土单轴抗压强度随水泥配合比增加而增大,且随冻融循环次数的增加而降低;7次冻融循环后,水泥配合比为8%～10%的改良黄土强度为初始值的50%左右并趋于稳定;7次冻融循环后,改良黄土黏聚力和内摩擦角趋于稳定;冻融后改良黄土压缩系数随水泥配合比增加而减少,且达到8%时压缩系数变化减缓。试验数据说明宝鸡地区8%水泥配合比改良黄土在有限次冻融循环作用后力学性能能够满足工程需求且水泥消耗较少。
In order to study the mechanical properties of cement-stabilized loess under freeze-thaw cycles, supported by the loess subgrade improvement project of Baoji-Lanzhou high-speed railway project, the changing law and internal mechanism of unconstrained compressive strength, shear strength and compression deformation of the original loess, remolded loess, and cement-stabilized loess with different cement ratios after a limited number of freeze-thaw cycles were studied indoor. The results show that the uniaxial compressive strength of cement-stabilized loess increases with cement mix ratio increases and decreases with number of freeze-thaw cycles increase; the strength of cement-stabilized loess with a cement mix ratio of 8% to 10% is about 50% of the initial value and tends to be stable after seven freeze-thaw cycles; the cohesion and internal friction angle of cement-stabilized loess tend to be stable after seven freeze-thaw cycles; the compression coefficient of cement-stabilized loess decreases with cement mix ratio increase after freezing and thawing, and the change of compressibility decreases at the ratio of 8%. Mixing 8% cement in Baoji area could improve the mechanical properties of the loess after a limited number of freeze-thaw cycles which could meet the engineering requirements with less cement consumption.
In order to study the mechanical properties of cement-stabilized loess under freeze-thaw cycles, supported by the loess subgrade improvement project of Baoji-Lanzhou high-speed railway project, the changing law and internal mechanism of unconstrained compressive strength, shear strength and compression deformation of the original loess, remolded loess, and cement-stabilized loess with different cement ratios after a limited number of freeze-thaw cycles were studied indoor. The results show that the uniaxial compressive strength of cement-stabilized loess increases with cement mix ratio increases and decreases with number of freeze-thaw cycles increase; the strength of cement-stabilized loess with a cement mix ratio of 8% to 10% is about 50% of the initial value and tends to be stable after seven freeze-thaw cycles; the cohesion and internal friction angle of cement-stabilized loess tend to be stable after seven freeze-thaw cycles; the compression coefficient of cement-stabilized loess decreases with cement mix ratio increase after freezing and thawing, and the change of compressibility decreases at the ratio of 8%. Mixing 8% cement in Baoji area could improve the mechanical properties of the loess after a limited number of freeze-thaw cycles which could meet the engineering requirements with less cement consumption.
引文
[1] Nelson J D,Miller D J.Expansive soils: Problems and practice in foundation and pavement engineering[M]. Wiley-Interscience,1997,10～27.
[2] R.Bahor,M.Benazzoug,S.Kenai.Performance of compacted cement stabilized soil[J]. Cement and Concrete Composites,2004,26(7): 812～820.
[3] 王谦,刘红玫,马海萍等.水泥改性黄土的抗液化特性与机制[J].岩土工程学报,2016,38(11):2128～2134.Wang Qian, Liu Hongmei, Ma Haiping et al. Liquefaction behavior and mechanism of cement-stabilized loess[J]. Chinese Journal of Geotechnical Engineering, 2016, 38(11): 2128～2134. (in Chinese)
[4] Wang S X,Lu Q F,Wang D K et al.Experimental study of clay minerals solidified by sodium silicate[J].Journal of Central South University(Science and Technology),2013,44(7): 2656～2662.
[5] 马学宁,梁波.水泥改良黄土力学特性试验研究[J].岩土工程技术,2005,19(5): 241～244.Ma Xuening, Liang Bo. Experimental study of mechanical performance of cement-improved loess[J]. Geotechnical Engineering Technique, 2005, 19(5): 241～244. (in Chinese)
[6] 吕擎峰,刘鹏飞,申贝等.温度改性水玻璃固化黄土冻融特性试验研究[J].工程地质学报,2015,23(1): 59～64.Lu Qingfeng, Liu Pengfei, Shen Bei et al. Laboratory study on peculiarity of loess solidified with temperature-modified sodium silicate under freeze-thaw cycles[J]. Journal of Engineering Geology, 2015, 23(1): 59～64. (in Chinese)
[7] 刘瑞锋.水泥改良土人工冻土性能及抑制冻胀融沉机理研究[D].上海: 同济大学,2006, 34～43. Liu Ruifeng. Performance of artificial frozen soil of cement modified soil and mechanism of suppression of frost heave and thaw[D]. Shanghai: Tongji University, 2006, 34～43. (in Chinese)
[8] 张军丽,刘保健.水泥黄土的力学特性试验研究[J].西安公路交通大学学报,1999,19(2): 6～9.Zhang Junli, Liu Baojian. The experiment research on the characteristics of cement loess[J]. Journal of Xi’an Highway University, 1999, 19(2): 6～9. (in Chinese)
[9] 王家鼎,彭淑君,马闫等.高速列车振动荷载下水泥改良黄土动力学试验[J].地震工程学报,2013,35(1): 35～41.Wang Jiading, Peng Shujun, Ma Yan et al. Dynamic tests on the cement-improved loess under the vibratory load[J]. China Earthquake Engineering Journal, 2013, 35(1): 35～41. (in Chinese)
[10] 刘潇敏,何小亮.水泥改良黄土力学特性试验研究[J].地下水,2011,33(5): 147～149.Liu Xiaomin, He Xiaoliang. Experiment study on mechanical properties of cement loess[J]. Ground Water, 2011, 33(5): 147～149. (in Chinese)
[11] 许健,王掌权,任建威等.原状与重塑黄土冻融过程渗透特性对比试验研究[J].工程地质学报,2017,25(2): 292～299.Xu Jian, Wang Zhangquan, Ren Jianwei et al. Comparative experimental study on permeability of undisturbed and remolded loess under freezing-thawing condition[J]. Journal of Engineering Geology, 2017, 25(2): 292～299. (in Chinese)
[12] 郭星,张齐齐,刘博榕等.水泥改良黄土试验研究[J].地下水,2015,37(3): 223～225.Guo Xing, Zhang Qiqi, Liu Borong et al. Experimental investigation on cement-stabilized loess[J]. Ground Water, 2015, 37(3): 223～225. (in Chinese)
[13] 杜伟飞,刘争宏,沈云霞等.聚丙烯纤维优化黄土改良土力学性能研究[J].工程勘察,2014,42(11):12～16,28.Du Weifei,Liu Zhenghong,Shen Yunxia et al. Study on optimizing mechanical properties of improved loess soil with polypropylene fiber[J]. Geotechnical Investigation & Surveying, 2014,42(11):12～16,28. (in Chinese)
[14] 周鹏,王逢睿,胡明珠等.新疆坎儿井井口砂土冻融破坏试验研究[J].工程勘察,2016,44(2):1～6.Zhou Peng,Wang Fengrui,Hu Mingzhu et al. Study on freeze-thaw destructive tests for wellhead sand of Karezes in Xinjiang[J]. Geotechnical Investigation & Surveying, 2016,44(2):1～6. (in Chinese)
[15] 李志清,余文龙,范林峰等.改良黄土强度特性与工程处置试验研究[J].工程地质学报,2011,19(1): 116～121.Li Zhiqing, Yu Wenlong, Fan Linfeng et al. Experimental research on strength characteristics and engineering treatment of improved loess soil[J]. Journal of Engineering Geology, 2011, 19(1): 116～121. (in Chinese)
[2] R.Bahor,M.Benazzoug,S.Kenai.Performance of compacted cement stabilized soil[J]. Cement and Concrete Composites,2004,26(7): 812～820.
[3] 王谦,刘红玫,马海萍等.水泥改性黄土的抗液化特性与机制[J].岩土工程学报,2016,38(11):2128～2134.Wang Qian, Liu Hongmei, Ma Haiping et al. Liquefaction behavior and mechanism of cement-stabilized loess[J]. Chinese Journal of Geotechnical Engineering, 2016, 38(11): 2128～2134. (in Chinese)
[4] Wang S X,Lu Q F,Wang D K et al.Experimental study of clay minerals solidified by sodium silicate[J].Journal of Central South University(Science and Technology),2013,44(7): 2656～2662.
[5] 马学宁,梁波.水泥改良黄土力学特性试验研究[J].岩土工程技术,2005,19(5): 241～244.Ma Xuening, Liang Bo. Experimental study of mechanical performance of cement-improved loess[J]. Geotechnical Engineering Technique, 2005, 19(5): 241～244. (in Chinese)
[6] 吕擎峰,刘鹏飞,申贝等.温度改性水玻璃固化黄土冻融特性试验研究[J].工程地质学报,2015,23(1): 59～64.Lu Qingfeng, Liu Pengfei, Shen Bei et al. Laboratory study on peculiarity of loess solidified with temperature-modified sodium silicate under freeze-thaw cycles[J]. Journal of Engineering Geology, 2015, 23(1): 59～64. (in Chinese)
[7] 刘瑞锋.水泥改良土人工冻土性能及抑制冻胀融沉机理研究[D].上海: 同济大学,2006, 34～43. Liu Ruifeng. Performance of artificial frozen soil of cement modified soil and mechanism of suppression of frost heave and thaw[D]. Shanghai: Tongji University, 2006, 34～43. (in Chinese)
[8] 张军丽,刘保健.水泥黄土的力学特性试验研究[J].西安公路交通大学学报,1999,19(2): 6～9.Zhang Junli, Liu Baojian. The experiment research on the characteristics of cement loess[J]. Journal of Xi’an Highway University, 1999, 19(2): 6～9. (in Chinese)
[9] 王家鼎,彭淑君,马闫等.高速列车振动荷载下水泥改良黄土动力学试验[J].地震工程学报,2013,35(1): 35～41.Wang Jiading, Peng Shujun, Ma Yan et al. Dynamic tests on the cement-improved loess under the vibratory load[J]. China Earthquake Engineering Journal, 2013, 35(1): 35～41. (in Chinese)
[10] 刘潇敏,何小亮.水泥改良黄土力学特性试验研究[J].地下水,2011,33(5): 147～149.Liu Xiaomin, He Xiaoliang. Experiment study on mechanical properties of cement loess[J]. Ground Water, 2011, 33(5): 147～149. (in Chinese)
[11] 许健,王掌权,任建威等.原状与重塑黄土冻融过程渗透特性对比试验研究[J].工程地质学报,2017,25(2): 292～299.Xu Jian, Wang Zhangquan, Ren Jianwei et al. Comparative experimental study on permeability of undisturbed and remolded loess under freezing-thawing condition[J]. Journal of Engineering Geology, 2017, 25(2): 292～299. (in Chinese)
[12] 郭星,张齐齐,刘博榕等.水泥改良黄土试验研究[J].地下水,2015,37(3): 223～225.Guo Xing, Zhang Qiqi, Liu Borong et al. Experimental investigation on cement-stabilized loess[J]. Ground Water, 2015, 37(3): 223～225. (in Chinese)
[13] 杜伟飞,刘争宏,沈云霞等.聚丙烯纤维优化黄土改良土力学性能研究[J].工程勘察,2014,42(11):12～16,28.Du Weifei,Liu Zhenghong,Shen Yunxia et al. Study on optimizing mechanical properties of improved loess soil with polypropylene fiber[J]. Geotechnical Investigation & Surveying, 2014,42(11):12～16,28. (in Chinese)
[14] 周鹏,王逢睿,胡明珠等.新疆坎儿井井口砂土冻融破坏试验研究[J].工程勘察,2016,44(2):1～6.Zhou Peng,Wang Fengrui,Hu Mingzhu et al. Study on freeze-thaw destructive tests for wellhead sand of Karezes in Xinjiang[J]. Geotechnical Investigation & Surveying, 2016,44(2):1～6. (in Chinese)
[15] 李志清,余文龙,范林峰等.改良黄土强度特性与工程处置试验研究[J].工程地质学报,2011,19(1): 116～121.Li Zhiqing, Yu Wenlong, Fan Linfeng et al. Experimental research on strength characteristics and engineering treatment of improved loess soil[J]. Journal of Engineering Geology, 2011, 19(1): 116～121. (in Chinese)