粗粒土的离心模型试验与数值模拟
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摘要
岩土工程数值计算中粗粒土常采用邓肯-张本构模型,为了验证该模型在轴向加载、卸载、侧向加载等复杂应力路径条件下的适用性,进行了粗粒土的三轴试验获取其力学特性及本构模型参数;根据相似性原理制作了堆石坝的离心模型试样,并采用与三轴试验同样级配与粒径的粗粒土进行复杂应力路径的堆石坝离心模型试验,试验中通过改变离心加速度模拟加载、卸载,利用上游蓄水模拟坝体的侧向加载;采用ABAQUS对离心模型试验进行三维数值模拟,并研究了模型箱侧壁摩擦系数与土体的初始应力对数值结果的影响。通过比较离心模型试验与数值模拟成果,表明土体的初始弹性模量对计算结果影响较大,初始应力应选择自重作用下的应力场;邓肯-张本构模型能较好地描述堆石坝的加载应力路径,而模拟卸载应力路径有一定的差异,需要改进邓肯-张本构模型中卸载模量的确定方法。
Duncan-Chang constitutive model is commonly used in the numerical analysis of the geotechnical problems related to coarse-grained soils. To explore the applicability of this model under complex stress path conditions including axial loading,unloading and lateral loading, a series of triaxial tests is conducted on coarse-grained soils to determine their mechanical properties and constitutive parameters. Based on the principle of similarity, the centrifugal models of a rockfill dam are prepared, and the centrifuge model test of a rockfill dam under complex stress path conditions is performed using the coars-grained soil with the same gradation and particle size in triaxial tests. The tests are conducted by changing the centrifugal acceleration to simulate loading and unloading conditions, and using the upstream impoundment to simulate the lateral loading. A three-dimensional numerical analysis of the centrifuge model test is performed using software ABAQUS. The effects of the sidewall friction and the initial stress conditions are studied. It is shown that the initial elastic modulus of soil can significantly influence the calculated results and the initial stress should assume the stress under the action of gravity in numerical simulations. Duncan-Chang constitutive model can better describe the behavious of the coarse-grained soil under the loading stress path than under the unloading stage; and thus the unloading modulus need to be determined with a proper method.
引文
[1]殷德顺,王保田,王云涛.不同应力路径下的邓肯-张模型模量公式[J].岩土工程学报,2007,29(9):1380-1386.YIN De-shun,WANG Bao-tian,WANG Yun-tao.Tangent elastic modulus of Duncan-Chang model for different stress paths[J].Chinese Journal of Geotechnical Engineering,2007,29(9):1380-1386.
    [2]张宗亮,贾延安,张丙印.复杂应力路径下堆石体本构模型比较验证[J].岩土力学,2008,29(5):1147-1151.ZHANG Zong-liang,JIA Yan-an,ZHANG Bing-yin.Comparison and verification of constitutive models for rockfill materials under complex stress path[J].Rock and Soil Mechanics,2008,29(5):1147-1151.
    [3]相彪,张宗亮,迟世春,等.复杂应力路径下堆石料本构关系研究[J].岩土力学,2010,31(6):1716-1723.XIANG Biao,ZHANG Zong-liang,CHI Shi-chun,et al.Study of constitutive relations of rockfill under complex stress path[J].Rock and Soil Mechanics,2010,31(6):1716-1723.
    [4]许萍,邵生俊,张喆,等.真三轴应力条件下修正邓肯-张模型的试验研究[J].岩土力学,2013,34(12):3359-3364.XU Ping,SHAO Sheng-jun,ZHANG Zhe,et al.Experimental study of modified Duncan-Chang model under true triaxial stresses[J].Rock and Soil Mechanics,2010,31(6):1716-1723.
    [5]杜延龄,韩连兵.土工离心模型试验技术[M].北京:中国水利水电出版社,2010.
    [6]钟锐,黄茂松.沉箱加桩复合基础地震响应离心试验[J].岩土力学,2014,35(2):380-388.ZHONG Rui,HUANG Mao-song.Centrifuge tests for seismic response of caisson-pile composite foundation[J].Rock and Soil Mechanics,2014,35(2):380-388.
    [7]徐光明,章为民.离心模型中的粒径效应和边界效应研究[J].岩土工程学报,1996,18(3):80-86.
    [8]章为民,唐剑虹.瀑布沟坝基防渗墙离心模型试验[J].岩土工程学报,1997,19(2):95-101.
    [9]包承纲,饶锡保.土工离心模型的试验原理[J].长江科学院院报,1998,15(2):1-3.BAO Cheng-gang,RAO Xi-bao.Principle of the geotechnical centrifuge model test[J].Journal of Yangtze River Scientific Research Institute,1998,15(2):1-3.
    [10]DUNCAN J M,CHANG C Y.Nonlinear analysis of stress and strain in soils[J].Journal of the Soil Mechanics and Foundations Division,ASCE,1970,96(SM5):1629-1653.

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