粗粒土的离心模型试验与数值模拟
发布时间：2018-11-15 16:45
【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。
[Abstract]:In order to verify the applicability of the model in complex stress paths, such as axial loading, unloading and lateral loading, the Duncan-Zhang Ben model is often used in geotechnical engineering numerical calculation. The mechanical properties and constitutive model parameters of coarse grained soil were obtained by triaxial test. According to the similarity principle, the centrifuge model sample of rockfill dam is made, and the centrifuge model test of rockfill dam with complex stress path is carried out by using the same gradation and coarse grained soil as triaxial test. The centrifugal acceleration is simulated by changing the centrifugal acceleration in the test. Unloading, using upstream water storage to simulate the lateral loading of dam body; The three-dimensional numerical simulation of centrifugal model test was carried out by ABAQUS, and the effects of friction coefficient of the side wall of the model box and the initial stress of soil on the numerical results were studied. By comparing the results of centrifugal model test and numerical simulation, it is shown that the initial elastic modulus of soil has a great influence on the calculation results, and the initial stress should be chosen as the stress field under the action of self-gravity. The Duncan-Zhang Ben model can describe the loading stress path of rockfill dam well, but there are some differences in simulating unloading stress path, so it is necessary to improve the method of determining unloading modulus in Duncan-Zhang Ben model.
【作者单位】： 长江科学院水利部岩土力学与工程重点实验室;
【基金】：国家自然科学基金项目(No.51309029,No.51309028) 水利部公益性行业科研专项(No.201201039)
【分类号】：TU411
[Abstract]:In order to verify the applicability of the model in complex stress paths, such as axial loading, unloading and lateral loading, the Duncan-Zhang Ben model is often used in geotechnical engineering numerical calculation. The mechanical properties and constitutive model parameters of coarse grained soil were obtained by triaxial test. According to the similarity principle, the centrifuge model sample of rockfill dam is made, and the centrifuge model test of rockfill dam with complex stress path is carried out by using the same gradation and coarse grained soil as triaxial test. The centrifugal acceleration is simulated by changing the centrifugal acceleration in the test. Unloading, using upstream water storage to simulate the lateral loading of dam body; The three-dimensional numerical simulation of centrifugal model test was carried out by ABAQUS, and the effects of friction coefficient of the side wall of the model box and the initial stress of soil on the numerical results were studied. By comparing the results of centrifugal model test and numerical simulation, it is shown that the initial elastic modulus of soil has a great influence on the calculation results, and the initial stress should be chosen as the stress field under the action of self-gravity. The Duncan-Zhang Ben model can describe the loading stress path of rockfill dam well, but there are some differences in simulating unloading stress path, so it is necessary to improve the method of determining unloading modulus in Duncan-Zhang Ben model.
【作者单位】： 长江科学院水利部岩土力学与工程重点实验室;
【基金】：国家自然科学基金项目(No.51309029,No.51309028) 水利部公益性行业科研专项(No.201201039)
【分类号】：TU411
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