π平面上原状土的空心扭剪试验
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摘要
为了通过空心扭剪试验获得原状土在π平面上的屈服特性,在分析空心扭剪试验仪加载过程和加载特点的基础上,研究了空心圆柱试样可实现的应力状态,并设计了相应的加载路径.与重塑试样不同,原状土样的初始应力状态位于K_0固结线上而不是等倾线上,因此,其加载路径应从原点开始沿K_0固结线行至原始应力状态,然后再在π平面上进行以初始应力为起点的等p试验.在考虑原状土的初始应力状态和各项异性的基础上,针对具有不同主应力方向角的平行试样,给出了等p条件下保持主应力方向角不变的加载路径实现方法,采用该方法可得到任意平均主应力时π平面上六分之一范围内的屈服曲线,该范围对应于大主应力方向角从-45°～45°.本文设计的加载方案可完成真三轴试验的部分功能,但经济成本相对较低,操作方法简单易行.
In order to obtain the yield characteristics of undisturbed soil on the π plane by hollow torsional shear test, based on the analysis of the loading process and loading characteristics of the hollow torsional shear tester, the stress state of the hollow cylindrical specimen was studied and the corresponding loading path was designed. Unlike the remolded specimen, the initial stress state of the undisturbed soil was on the K_0 consolidation line rather than the equipotential line. Therefore, the loading path starts from the origin along the K_0 consolidation line to the original stress state, and then follows an iso-p test starting from the initial stress on the π plane.Considering the initial stress state and anisotropy of the undisturbed soil, the loading path method for keeping the principal stress direction angle unchanged under equal-p conditions was given for the parallel specimens with different principal stress directions.The yield curve in the range of one-sixth of the π plane at any average principal stress can be obtained. This range corresponds to the direction of the large principal stress from -45°～45°. The loading scheme proposed in this paper can realize some characters of the true triaxial test, with relatively low economic cost, and simplified operation scheme.
In order to obtain the yield characteristics of undisturbed soil on the π plane by hollow torsional shear test, based on the analysis of the loading process and loading characteristics of the hollow torsional shear tester, the stress state of the hollow cylindrical specimen was studied and the corresponding loading path was designed. Unlike the remolded specimen, the initial stress state of the undisturbed soil was on the K_0 consolidation line rather than the equipotential line. Therefore, the loading path starts from the origin along the K_0 consolidation line to the original stress state, and then follows an iso-p test starting from the initial stress on the π plane.Considering the initial stress state and anisotropy of the undisturbed soil, the loading path method for keeping the principal stress direction angle unchanged under equal-p conditions was given for the parallel specimens with different principal stress directions.The yield curve in the range of one-sixth of the π plane at any average principal stress can be obtained. This range corresponds to the direction of the large principal stress from -45°～45°. The loading scheme proposed in this paper can realize some characters of the true triaxial test, with relatively low economic cost, and simplified operation scheme.
引文
[1]周建,张金良,沈扬,等.原状软黏土空心圆柱试样制备研究[J].岩土工程学报,2007,4:618-621.
[2]周辉,姜玥,卢景景,等.岩石空心圆柱扭剪仪试验能力[J].岩土力学,2018,39(5):1917-1922.
[3]周正龙,陈国兴,吴琪.四向振动空心圆柱扭剪仪模拟主应力轴旋转应力路径能力分析[J].岩土力学,2016,37(S1):126-132.
[4]董彤,郑颖人,孔亮,等.空心圆柱扭剪试验中广义应力路径的控制与实现[J].岩土工程学报,2017,39(S1):106-110.
[5]潘华,陈国兴.动态围压下空心圆柱扭剪仪模拟主应力轴旋转应力路径能力分析[J].岩土力学,2011,32(6):1701-1706,1712.
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[8]林清辉,严佳佳,董梅,等.大主应力方向及中主应力系数对重塑黄土小应变刚度特性影响试验研究[J].岩土力学,2018,39(4):1369-1376.
[9]周辉,姜玥,卢景景,等.岩石空心圆柱扭剪试验系统研制[J].岩土力学,2018,39(4):1535-1542.
[10]沈扬,周建,张金良,等.新型空心圆柱仪的研制与应用[J].浙江大学学报:工学版,2007,41(9):1450-1456.
[11]郭万里,席欢,宋秋璐.端部效应对土体三轴扭剪试样应力分布的影响[J].河北工程大学学报:自然科学版,2015,32(4):25-28.
[12]罗有权,张黎红,董则军.试样壁厚对扭剪应力不均匀分布的影响[J].水电能源科学,2017,35(5):145-148.
[13]周建,张金良,沈扬,等.浙江大学5Hz空心圆柱仪试样固结变形研究[J].岩石力学与工程学报,2008,27(S1):3023-3027.
[14]李博,黄茂松.空心圆柱扭转仪定向剪切试验离散元模拟[J].岩土力学,2016,37(4):1161-1170.
[15]李顺群,高凌霞,尚军.常规三轴试验固结阶段的理论研究及试验验证[J].工业建筑,2014,44(2):72-76+68.
[16]李顺群,贾红晶,夏锦红,等.考虑原状土初始应力状态的修正SMP屈服准则[J].水文地质工程地质,2015,42(3):102-107.
[17]SHAO L,GUO X,LIU S,et al.Effective stress and equilibrium equation for soil mechanics[M].London:Taylor&Francis Group CRC Press,2017.
[18]李顺群,张来栋,夏锦红,等.土的应力状态和基于Mohr-Coulomb准则的结构性模型[J].中国公路学报,2014,27(11):1-10.
[19]李顺群,夏锦红,张培印.初始应力线和原状土的修正Mohr-Coulomb准则[J].工程力学,2016,33(7):116-122.
[20]张来栋,李顺群,夏锦红.土体的实质应力和非极限状态[J].武汉理工大学学报,2014,36(4):116-120.
[2]周辉,姜玥,卢景景,等.岩石空心圆柱扭剪仪试验能力[J].岩土力学,2018,39(5):1917-1922.
[3]周正龙,陈国兴,吴琪.四向振动空心圆柱扭剪仪模拟主应力轴旋转应力路径能力分析[J].岩土力学,2016,37(S1):126-132.
[4]董彤,郑颖人,孔亮,等.空心圆柱扭剪试验中广义应力路径的控制与实现[J].岩土工程学报,2017,39(S1):106-110.
[5]潘华,陈国兴.动态围压下空心圆柱扭剪仪模拟主应力轴旋转应力路径能力分析[J].岩土力学,2011,32(6):1701-1706,1712.
[6]GUO W L,ZHU J G,YIN J H,et al.Investigation into the effects of the thickness of a hollow-cylinder soil specimen on the stress distributions in triaxial torsional shear testing[J].Geotechnical Testing Journal,2016,39(5):786-794.
[7]ZHAO X L,EVANS T M.Discrete simulations of laboratory loading conditions[J].International Journal of Geomechanics,2009,9(4):169-178.
[8]林清辉,严佳佳,董梅,等.大主应力方向及中主应力系数对重塑黄土小应变刚度特性影响试验研究[J].岩土力学,2018,39(4):1369-1376.
[9]周辉,姜玥,卢景景,等.岩石空心圆柱扭剪试验系统研制[J].岩土力学,2018,39(4):1535-1542.
[10]沈扬,周建,张金良,等.新型空心圆柱仪的研制与应用[J].浙江大学学报:工学版,2007,41(9):1450-1456.
[11]郭万里,席欢,宋秋璐.端部效应对土体三轴扭剪试样应力分布的影响[J].河北工程大学学报:自然科学版,2015,32(4):25-28.
[12]罗有权,张黎红,董则军.试样壁厚对扭剪应力不均匀分布的影响[J].水电能源科学,2017,35(5):145-148.
[13]周建,张金良,沈扬,等.浙江大学5Hz空心圆柱仪试样固结变形研究[J].岩石力学与工程学报,2008,27(S1):3023-3027.
[14]李博,黄茂松.空心圆柱扭转仪定向剪切试验离散元模拟[J].岩土力学,2016,37(4):1161-1170.
[15]李顺群,高凌霞,尚军.常规三轴试验固结阶段的理论研究及试验验证[J].工业建筑,2014,44(2):72-76+68.
[16]李顺群,贾红晶,夏锦红,等.考虑原状土初始应力状态的修正SMP屈服准则[J].水文地质工程地质,2015,42(3):102-107.
[17]SHAO L,GUO X,LIU S,et al.Effective stress and equilibrium equation for soil mechanics[M].London:Taylor&Francis Group CRC Press,2017.
[18]李顺群,张来栋,夏锦红,等.土的应力状态和基于Mohr-Coulomb准则的结构性模型[J].中国公路学报,2014,27(11):1-10.
[19]李顺群,夏锦红,张培印.初始应力线和原状土的修正Mohr-Coulomb准则[J].工程力学,2016,33(7):116-122.
[20]张来栋,李顺群,夏锦红.土体的实质应力和非极限状态[J].武汉理工大学学报,2014,36(4):116-120.
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