基质吸力对非饱和滑带土抗剪强度的影响试验研究
|
摘要
在滑坡地质灾害中遇到的滑带土大多数是非饱和土,研究吸力对非饱和滑带土c、φ值的影响,对于滑坡防治具有十分重要的意义。本文通过不同基质吸力和剪切速率的条件下的四联直剪试验,探讨了基质吸力与非饱和粘性滑带土抗剪强度的关系。试验结果表明:在同一基质吸力条件下,抗剪强度随轴向荷载的增大而增大,且保持平稳线性增长的趋势;随着吸力值的增大,其总粘聚力与内摩擦角均呈现增大趋势。对于总粘聚力来说,当基质吸力≤100kPa时,随着吸力的增大,总粘聚力增长曲线斜率较大,增长速率较快;当基质吸力>100kPa时,随着吸力值的增大,总粘聚力增长曲线斜率放缓,增长速率减慢,但总体处于平稳增长的态势。对于内摩擦角来说,当基质吸力≤50kPa时,随着吸力的增大,内摩擦角增长曲线斜率较大,增长速率较快;当基质吸力>50kPa时,随着吸力值的增大,内摩擦角增长曲线斜率放缓,增长速率减慢。
The soil in slide zone is always unsaturated. It is very important to study the influence of suction on the unsaturated slip soil and their shear strength in landslide prevention works. The relationship between matric suction and the shear strength of unsaturated viscous slippage is discussed through quadruple shear tests under the condition of different substrate suction and shear rate. The experimental results show that the shear strength increases with the increase of axial load in the same matric, and the trend of stable linear growth is maintained. With the increase of suction, the total cohesion and internal friction angle show an increasing trend. For total cohesion, when the matrix suction less than or equal to 100 kPa, with the increase of suction, the growth curve of the total cohesive force growth curve is larger and the growth rate is faster; when the matric suction is great than 100 kPa, with the suction value increases, the slope of the total cohesion growth curve becomes gentle and the growth rate slows down, but the overall situation is steady growth. For internal friction angle, when matrix suction less than or equal to 50 kPa, with the increase of suction force, the growth curve of internal friction angle is larger and the growth rate is faster. When the matric suction is greater than 50 kPa, with the increase of suction value, the slope of the growth curve of internal friction angle decreases and the growth rate slows down.
The soil in slide zone is always unsaturated. It is very important to study the influence of suction on the unsaturated slip soil and their shear strength in landslide prevention works. The relationship between matric suction and the shear strength of unsaturated viscous slippage is discussed through quadruple shear tests under the condition of different substrate suction and shear rate. The experimental results show that the shear strength increases with the increase of axial load in the same matric, and the trend of stable linear growth is maintained. With the increase of suction, the total cohesion and internal friction angle show an increasing trend. For total cohesion, when the matrix suction less than or equal to 100 kPa, with the increase of suction, the growth curve of the total cohesive force growth curve is larger and the growth rate is faster; when the matric suction is great than 100 kPa, with the suction value increases, the slope of the total cohesion growth curve becomes gentle and the growth rate slows down, but the overall situation is steady growth. For internal friction angle, when matrix suction less than or equal to 50 kPa, with the increase of suction force, the growth curve of internal friction angle is larger and the growth rate is faster. When the matric suction is greater than 50 kPa, with the increase of suction value, the slope of the growth curve of internal friction angle decreases and the growth rate slows down.
引文
[1] 林鸿州,李广信,于玉贞等.基质吸力对非饱和土抗剪强度的影响[J].岩土力学,2007,28(9):1931～1937.Lin Hongzhou, Li Guangxin, Yu Yuzhen et al. Influence of matric suction on shear strength behavior of unsaturated soils[J].Rock and Soil Mechanics, 2007,28(9):1931～1937.(in Chinese)
[2] 刘星志,陈铭,陈小燕等.基质吸力在不同干密度下对非饱和土抗剪强度的影响[J].中国农村水利水电,2017,(3):126～131.Liu Xingzhi,Chen Ming,Chen Xiaoyan et al. The influence of matric suction on shear strength behavior of unsaturated laterites under different dry densities[J]. China Rural Water and Hydropower, 2017,(3):126～131.(in Chinese)
[3] 郭倩怡,谷天峰,吴熠哲.永靖非饱和黄土抗剪强度试验研究[J].水文地质工程地质,2015,42(6):103～108.Guo Qianyi, Gu Tianfeng, Wu Yizhe. A test study of shear strength of unsaturated loess in Yongjing County[J]. 2015,42(6):103～108.(in Chinese)
[4] 曹玲,罗先启,徐永福.非饱和土边坡滑带土恒荷载试验研究[J].岩土工程学报,2010,32(S2):146～150.Cao Ling, Luo Xianqi, Xu Yongfu. Dead load test study of unsaturated soil slope[J]. Chinese Journal of Geotechnical Engineering,2010,32(S2):146～150.(in Chinese)
[5] 戚国庆.降雨诱发滑坡机理及其评价方法研究——非饱和土力学理论在降雨型滑坡研究中的应用[D].成都:成都理工大学, 2004.Qi Guoqing.Study on the mechanics of rainfall-induced landslide and its evaluating method: The research of landslide due to rainfall applying theories of unsaturated soils mechanics[D].Chengdu: Chendu University of Technology,2004.(in Chinese)
[6] 周林根,叶宇旻.考虑降雨入渗的非饱和边坡动力稳定性分析[J].工程勘察,2014,42(10):6～8.Zhou Lingen, Ye Yumin. Dynamic stability analysis of unsaturated slope considering rainfall infiltration process[J]. Geotechnical Investigation & Surveying,2014,42(10):6～8.(in Chinese)
[7] Fredlund D G,Morgenstern N R, Widger R A. The shear strength of unsaturated soils[J]. Canadian Geotechnical Journal, 1978,15(3):313～321.
[8] 刘祖典, 刘武农. 非饱和土的强度特性[J]. 工程勘察,1999,(1):7～9.Liu Zudian, Liu Wulong. Strength characteristics of unsaturated soils[J]. Geotechnical Investigation & Surveying,1999,(1):7～9.(in Chinese)
[9] 黄润秋,吴礼舟.非饱和土抗剪强度的研究[J].成都理工大学学报,2007,34(3):221～224.Huang Runqiu, Wu Lizhou. Study on the shear strength of unsaturated expansive soils[J]. Journal of Chengdu University of Technology,2007,34(3):221～224.(in Chinese)
[10] 扈胜霞,周云东,陈正汉.非饱和原状黄土强度特性的试验研究[J].岩土力学,2005,26(4):660～663.Hu Shengxia, Zhou Yundong, Chen Zhenghan. Test study on strength character of unsaturated and undisturbed loess[J]. Rock and Soil Mechanics,2005,26(4):660～663.(in Chinese)
[11] Gan J K,Fredlund D G,Rahardjo H. Determination of shear parameters of an unsaturated soil using the direct shear test[J]. Canadian Geotechnical Journal, 1988,25(3):500～510.
[2] 刘星志,陈铭,陈小燕等.基质吸力在不同干密度下对非饱和土抗剪强度的影响[J].中国农村水利水电,2017,(3):126～131.Liu Xingzhi,Chen Ming,Chen Xiaoyan et al. The influence of matric suction on shear strength behavior of unsaturated laterites under different dry densities[J]. China Rural Water and Hydropower, 2017,(3):126～131.(in Chinese)
[3] 郭倩怡,谷天峰,吴熠哲.永靖非饱和黄土抗剪强度试验研究[J].水文地质工程地质,2015,42(6):103～108.Guo Qianyi, Gu Tianfeng, Wu Yizhe. A test study of shear strength of unsaturated loess in Yongjing County[J]. 2015,42(6):103～108.(in Chinese)
[4] 曹玲,罗先启,徐永福.非饱和土边坡滑带土恒荷载试验研究[J].岩土工程学报,2010,32(S2):146～150.Cao Ling, Luo Xianqi, Xu Yongfu. Dead load test study of unsaturated soil slope[J]. Chinese Journal of Geotechnical Engineering,2010,32(S2):146～150.(in Chinese)
[5] 戚国庆.降雨诱发滑坡机理及其评价方法研究——非饱和土力学理论在降雨型滑坡研究中的应用[D].成都:成都理工大学, 2004.Qi Guoqing.Study on the mechanics of rainfall-induced landslide and its evaluating method: The research of landslide due to rainfall applying theories of unsaturated soils mechanics[D].Chengdu: Chendu University of Technology,2004.(in Chinese)
[6] 周林根,叶宇旻.考虑降雨入渗的非饱和边坡动力稳定性分析[J].工程勘察,2014,42(10):6～8.Zhou Lingen, Ye Yumin. Dynamic stability analysis of unsaturated slope considering rainfall infiltration process[J]. Geotechnical Investigation & Surveying,2014,42(10):6～8.(in Chinese)
[7] Fredlund D G,Morgenstern N R, Widger R A. The shear strength of unsaturated soils[J]. Canadian Geotechnical Journal, 1978,15(3):313～321.
[8] 刘祖典, 刘武农. 非饱和土的强度特性[J]. 工程勘察,1999,(1):7～9.Liu Zudian, Liu Wulong. Strength characteristics of unsaturated soils[J]. Geotechnical Investigation & Surveying,1999,(1):7～9.(in Chinese)
[9] 黄润秋,吴礼舟.非饱和土抗剪强度的研究[J].成都理工大学学报,2007,34(3):221～224.Huang Runqiu, Wu Lizhou. Study on the shear strength of unsaturated expansive soils[J]. Journal of Chengdu University of Technology,2007,34(3):221～224.(in Chinese)
[10] 扈胜霞,周云东,陈正汉.非饱和原状黄土强度特性的试验研究[J].岩土力学,2005,26(4):660～663.Hu Shengxia, Zhou Yundong, Chen Zhenghan. Test study on strength character of unsaturated and undisturbed loess[J]. Rock and Soil Mechanics,2005,26(4):660～663.(in Chinese)
[11] Gan J K,Fredlund D G,Rahardjo H. Determination of shear parameters of an unsaturated soil using the direct shear test[J]. Canadian Geotechnical Journal, 1988,25(3):500～510.