EVP模型中参考时间的选取研究
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摘要
非线性弹黏塑性(EVP)模型可以较好地预测软土的流变固结过程,但是在根据一维流变固结试验数据确定其材料参数时需要合理确定参考时间。为进一步探究参考时间的选取对EVP模型参数的影响,文章介绍了基于EVP模型的一维流变固结方程,并给出了Crank-Nicolson有限差分数值求解格式。同时以河南某地饱和软黏土为研究对象,进行了一系列一维流变固结试验。对应选取的不同参考时间,确定了EVP模型参数,并将竖向应变的计算值与试验值进行了比较。分析表明,参考时间的选取对初始次固结系数的影响较小,而对模型参考时间线参数和参考应力点的影响较大;另外,参考时间取单位时间能更好的模拟整个固结过程。
The non-linear elastic visco-plastic( EVP) model can be used to well predict the rheological consolidation process of soft soil,but the reference time should be determined reasonably before the model 's parameters are done based on one-dimensional rheological consolidation test. To further investigate the selection of the reference time to the effect of the EVP model's parameters,the one-dimensional rheological consolidation equation based on EVP model was introduced,and its numerical analysis was conducted by the Crank-Nicolson finite difference method. A series of one dimensional rheological consolidation tests were performed for the saturated soft clay in Henan. The model 's parameters were determined for some different reference times,and the numerical solution of vertical strains was compared with the experimental data. The results shows that the reference time has no influence on the initial coefficient of second consolidation,while it does more influence on the parameters of the reference time line and the reference stress point. Moreover,the whole consolidation process can be better simulated by using the unit time as the reference time.
The non-linear elastic visco-plastic( EVP) model can be used to well predict the rheological consolidation process of soft soil,but the reference time should be determined reasonably before the model 's parameters are done based on one-dimensional rheological consolidation test. To further investigate the selection of the reference time to the effect of the EVP model's parameters,the one-dimensional rheological consolidation equation based on EVP model was introduced,and its numerical analysis was conducted by the Crank-Nicolson finite difference method. A series of one dimensional rheological consolidation tests were performed for the saturated soft clay in Henan. The model 's parameters were determined for some different reference times,and the numerical solution of vertical strains was compared with the experimental data. The results shows that the reference time has no influence on the initial coefficient of second consolidation,while it does more influence on the parameters of the reference time line and the reference stress point. Moreover,the whole consolidation process can be better simulated by using the unit time as the reference time.
引文
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[2]Yin J H,Graham J.Viscous-elastic-plastic modelling of one-dimensional time-dependent behaviour of clays[J].Canadian Geotechnical Journal,1989,26(2):199-209.
[3]殷建华,Clark J.土体与时间相关的一维应力-应变性状、"粘塑性模型和固结分析[J].岩土力学,1994,15(3):66-80.
[4]殷建华,Clark J.土体与时间相关的一维应力-应变性状、"粘塑性模型和固结分析(续)[J].岩土力学,1994,15(4):66-75.
[5]Yin J H,Graham J.Equivalent times and onedimensional elastic viscoplastic modelling of timedependent stress-strain behaviourof clays[J].Canadian Geotechnical Journal,1994,31(1):42-52.
[6]Yin J H,Graham J.Elastic visco-plastic modelling of one-dimensional consolidation[J].Geotechnique,1996,46(3):515-527.
[7]Yin J H,Zhu J G.Measured and predicted timedependent stress-strain behaviour of Hongkong marine deposits[J].Canadian Geotechnical Journal,1999,36(4):760-766
[8]Yin J H.Non-linear creep of soils in oedometer tests[J].Geotechnique,1999,49(5):699-707.
[9]Yin J H,Zhu J G,Graham J.A new elastic viscoplastic model for time-dependent behaviour of normally and overconsolidated clays:theory and verification[J].Canadian Geotechnical Journal,2002,39(1):157-173
[10]Degago S A,Grimstad G,Jostad H P,et al.The nonuniqueness of the end-of-primary(EOP)void ratioeffective stress relationship[A]//Proceedings of the17th International Conference on Soil Mechanics and Geotechnical Engineering[C].Alexandria,2009:324-327.
[11]雷华阳,王学超,丁小冬.软土主次固结划分及影响因素探讨[J].工程地质学报,2014,22(3):489-497.
[12]Le T,Behzad F,Hadi K,et al.Numerical optimization applying trust-region reflective least squares algorithm with constraints to optimize the non-linear creep parameters of soft soil[J].Applied Mathematical Modelling,2016,16(19):1-12
[13]Le T,Behzad F,Mahdi M,et al.Analyzing consolidation data to obtain elastic viscoplastic parameters of clay[J].Geomechanics and Engineering2015,8(4):559-594
[14]中国人民共和国建设部.土工试验方法标准(GB/T50123-1999)[S].北京:中国计划出版社,1999.
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[16]朱俊高,王元龙,贾华.粗粒土回弹特性试验研究[J].岩土工程学报,2011,33(6):950-954.
[17]章为民,顾行文,王芳.土的卸荷回弹试验及其时间过程的计算方法[J].岩土工程学报,2015,37(6):979-987.