高应力作用下尾砂非线性剪切强度特性研究
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摘要
尾矿强度参数是影响尾矿坝体稳定分析的关键因素。基于室内尾砂三轴加载试验成果,对高应力条件下尾砂非线性强度特性予以研究。试验结果表明:高应力尾砂的三轴固结不排水剪切曲线具有明显软化特性,曲线软化程度随着围压的增大而增大。根据三轴应力-应变曲线建立了描述尾砂应变软化现象的改进双曲线模型,采用二次抛物线型、幂函数型的包络线描述强度特征的非线性。对比结果表明,幂函数型Mohr强度准则作为高应力条件下尾砂破坏的强度判据,具有较高精度。等效法向应力与内摩擦角正切值的函数关系表明,高应力条件下尾砂的内摩擦角不是一个定值,而具有幂函数型非线性特征。
The tailings strength parameters is the key factor that affects the analysis of tailings dam stability. Based on triaxial tests under high stresses,the nonlinear strength property of tailings was validated. The results showed that the triaxial consolidation undrained shear curves had obviously softening characteristics,and the degree of strain softening increased as the stresses increased. According to triaxial stress-strain curves,an improved hyperbola model was set up for describing the phenomenon of tailings sand strain softening. The quadratic parabolic and power exponent function of envelope lines were adopted to describe the nonlinearity of strength characteristics,and the comparison results showed that the power exponent function of Mohr envelope had high precision as the criterion of breaking strength of tailings sand under high stresses. The function of equivalent normal stress and tangent value of internal friction angle indicated that the internal friction angle of tailings sand under high stresses was not a fixed value,but had nonlinearity characteristics of power exponent function.
The tailings strength parameters is the key factor that affects the analysis of tailings dam stability. Based on triaxial tests under high stresses,the nonlinear strength property of tailings was validated. The results showed that the triaxial consolidation undrained shear curves had obviously softening characteristics,and the degree of strain softening increased as the stresses increased. According to triaxial stress-strain curves,an improved hyperbola model was set up for describing the phenomenon of tailings sand strain softening. The quadratic parabolic and power exponent function of envelope lines were adopted to describe the nonlinearity of strength characteristics,and the comparison results showed that the power exponent function of Mohr envelope had high precision as the criterion of breaking strength of tailings sand under high stresses. The function of equivalent normal stress and tangent value of internal friction angle indicated that the internal friction angle of tailings sand under high stresses was not a fixed value,but had nonlinearity characteristics of power exponent function.
引文
[1]张兴凯,孙恩吉,李仲学.尾矿库洪水漫顶溃坝演化规律试验研究[J].中国安全科学学报,2011,21(7):118-124.
[2]杨凯,吕淑然,张媛媛.尾矿坝中尾砂的强度特性试验研究[J].金属矿山,2014(2):166-170.
[3]王凤江.上游法高尾矿坝的抗震问题[J].冶金矿山设计与建设,2001,33(5):10-13.
[4]赵光思,周国庆,朱锋盼,等.颗粒破碎影响砂直剪强度的试验研究[J].中国矿业大学学报,2008,37(3):291-294.
[5]殷家瑜,赖安宁,姜朴.高压力下尾矿砂的强度与变形特性[J].岩土工程学报,1980,2(2):1-10.
[6]刘海明,杨春和,张超,等.高压下尾矿材料幂函数型莫尔强度特性研究[J].岩土力学,2012,33(7):1986-1992.
[7]Norihiko Miura,Toyotoshi Yamanouchi.Effect of Water on the Behavior of A Quartz-Rich Sand Under High Stresses[J].Soils and Foundations,1975,15(4):23-34.
[8]尹光志,张千贵,魏作安,等.尾矿细微观力学与变形观测试验装置的研制与应用[J].岩石力学与工程学报,2011,30(5):926-934.
[9]Charles J A,Watts K S.The Influence of Confining Pressure on the Shear Strength of Compacted Rockfill[J].Geotechnique,1980,30(4):353-367.
[10]Lee Y H.Strength and Deformation Characteristics of Rockfill[D].Bangkok:Asian Institute of Technology,1986.
[11]甘霖,袁光国.大型高压三轴试验测试及粗粒土的强度特性[J].大坝观测与土工测试,1997,21(3):9-12.
[12]Kondner A M.Hyperbolic Stress-Strain Response:Cohensive Soils[J].Journal of the Soil Mechanics and Foundations Division,ASCE,1963,89(SM1):115-143.
[13]Duncan J M,Chang C Y.Nonlinear Analysis of Stress and Strain in Soils[J].Journal of the Soil Mechanics and Foundations Division,1970,96(5):1629-1653.
[14]石祥超,孟英峰,李皋.几种岩石强度准则的对比分析[J].岩土力学,2011,32(S1):209-216.
[15]李新平,赵航,肖桃李.锦屏大理岩卸荷本构模型与数值模拟研究[J].岩土力学,2012,33(S2):401-407.
[16]卢晓春,田斌,孙开畅.考虑强度参数非线性的粗粒料坝坡稳定性[J].武汉大学学报:工学版,2014,47(1):34-38.
[17]汪斌,朱杰兵,邬爱清,等.高应力下岩石非线性强度特性的试验验证[J].岩石力学与工程学报,2010,28(3):542-548.
[2]杨凯,吕淑然,张媛媛.尾矿坝中尾砂的强度特性试验研究[J].金属矿山,2014(2):166-170.
[3]王凤江.上游法高尾矿坝的抗震问题[J].冶金矿山设计与建设,2001,33(5):10-13.
[4]赵光思,周国庆,朱锋盼,等.颗粒破碎影响砂直剪强度的试验研究[J].中国矿业大学学报,2008,37(3):291-294.
[5]殷家瑜,赖安宁,姜朴.高压力下尾矿砂的强度与变形特性[J].岩土工程学报,1980,2(2):1-10.
[6]刘海明,杨春和,张超,等.高压下尾矿材料幂函数型莫尔强度特性研究[J].岩土力学,2012,33(7):1986-1992.
[7]Norihiko Miura,Toyotoshi Yamanouchi.Effect of Water on the Behavior of A Quartz-Rich Sand Under High Stresses[J].Soils and Foundations,1975,15(4):23-34.
[8]尹光志,张千贵,魏作安,等.尾矿细微观力学与变形观测试验装置的研制与应用[J].岩石力学与工程学报,2011,30(5):926-934.
[9]Charles J A,Watts K S.The Influence of Confining Pressure on the Shear Strength of Compacted Rockfill[J].Geotechnique,1980,30(4):353-367.
[10]Lee Y H.Strength and Deformation Characteristics of Rockfill[D].Bangkok:Asian Institute of Technology,1986.
[11]甘霖,袁光国.大型高压三轴试验测试及粗粒土的强度特性[J].大坝观测与土工测试,1997,21(3):9-12.
[12]Kondner A M.Hyperbolic Stress-Strain Response:Cohensive Soils[J].Journal of the Soil Mechanics and Foundations Division,ASCE,1963,89(SM1):115-143.
[13]Duncan J M,Chang C Y.Nonlinear Analysis of Stress and Strain in Soils[J].Journal of the Soil Mechanics and Foundations Division,1970,96(5):1629-1653.
[14]石祥超,孟英峰,李皋.几种岩石强度准则的对比分析[J].岩土力学,2011,32(S1):209-216.
[15]李新平,赵航,肖桃李.锦屏大理岩卸荷本构模型与数值模拟研究[J].岩土力学,2012,33(S2):401-407.
[16]卢晓春,田斌,孙开畅.考虑强度参数非线性的粗粒料坝坡稳定性[J].武汉大学学报:工学版,2014,47(1):34-38.
[17]汪斌,朱杰兵,邬爱清,等.高应力下岩石非线性强度特性的试验验证[J].岩石力学与工程学报,2010,28(3):542-548.