粉煤灰是一种不同于粘土的散粒状材料, 其应力比应变关系与平均应力和初始孔隙比有关. 对不同初始孔隙比的粉煤灰试样在不同围压下实施三轴固结排水剪切试验, 测得其应力应变关系, 并对考虑平均应力和初始孔隙比影响的临界状态模型进行部分修正, 模拟不同初始孔隙比粉煤灰试样的三轴固结排水剪切试验结果. 结果表明, 修正模型对粉煤灰临界状态线进行了简单的修正, 并且模型中状态参数和硬化/软化参数的应用较好地描述了粉煤灰的剪胀/剪缩和应变硬化/软化等特性.
Being different from clay, fly ash is a kind of granular material. The stress ratio-strain relation of fly ash is related to both mean stress and void ratio. A number of consolidated-drained triaxial tests were carried out on a fly ash with different initial void ratios under different confining pressures. Relevant stress-strain relations have been obtained. Simple modifications have been made to the elastoplastic model proposed by Yao, et al., which considers the mean stress and initial void ratio. The mechanical behavior of fly ash specimens with different initial void ratios from drained triaxial tests are consistently predicted by the modified model. The application of the state parameter and hardening/softening parameters in the critical state model can predict dilatancy, hardening and
softening characteristics of the fly ash.
[1] 刘兴德, 牛福生, 倪文. 粉煤灰的资源化利用现状与研究进展[J]. 建材技术与应用, 2005(1): 12-15.
[2] 冯海宁, 杨有海, 龚晓南. 粉煤灰工程特性的试验研究[J].岩土力学, 2002, 23(5): 579-582.
[3] Roscoe K H, Burland J B. On the generalised stressstrain behavior of “wet” clay [M]. Cambridge: Cambridge Press, 1968: 535-609.
[4] 姚仰平, 余亚妮. 基于统一硬化参数的砂土临界状态本构模型[J]. 岩土工程学报, 2011, 33(12): 1827-1832.
[5] Pestana J M, Whittle A J. Formulation of a unified constitutive model for clays and sands [J]. International Journal for Numerical Methods in Geomechanics, 1999,
23(12): 1215-1243.
[6] Verdugo R, Ishihara K. The steady state of sandy soils [J]. Soils and Foundations, 1996, 36(2): 81-91.
[7] Li X S, Wang Y. Linear representation of steady-state line for sand [J]. Journal of Geotechnical Engineering, 1998, 124(12): 1215-1217.
[8] Been K, Jefferies M G. A state parameter for sands [J]. Geotechnique, 1985, 35(1): 99-112.
[9] Yao Y P, Sun D A, Luo T. A critical state model for sands dependent on stress and density [J]. International Journal for Numerical and Analytical Methods in Geomechanics,
2004, 28(4): 323-337.
[10] Li X S, Dafalias Y F. Dilatancy for cohesionless soils [J]. Geotechnique, 2000, 50(4): 449-460.
