邓肯-张EB模型参数求解的二次优化法

发布时间：2018-04-30 16:58

  本文选题：堆石料 + 邓肯-张模型　； 参考：《水力发电》2017年08期

【摘要】：邓肯-张非线性弹性模型是土石坝工程中最常用的本构模型。水利行业《土工试验规程》中根据应力水平75%和90%两点法进行计算时,得到的结果往往并不合理,有时n值还可能出现负数。一般的适线法仅仅对单个试样结果进行优化,而并不是针对整组试验结果,因此无法得到最优结果。提出了一种二步优化的参数计算方法,首先对每级围压下单个试样的试验成果采用适线法优化,得到每级围压下的参数a、b。在此基础上,计算得到参数K、n、Rf的初值。然后以邓肯-张理论为基础,根据获得的参数初值针对整组试验成果进行二次优化,以理论计算与试验的应力应变曲线差的平方和最小为目标函数,从而得到EB模型的主要参数。该方法简单实用,能够快速和准确地获得邓肯-张模型参数,并结合糯扎渡大坝堆石料三轴试验数据,对方法进行了验证。
[Abstract]:Duncan-Zhang nonlinear elastic model is the most commonly used constitutive model in earth-rock dam engineering. According to the stress level of 75% and 90%, the results obtained in geotechnical test code of water conservancy industry are often unreasonable, and sometimes the value of n may be negative. The general line fitting method only optimizes the results of a single sample, but not for the whole set of test results, so it is impossible to obtain the optimal results. In this paper, a two-step parameter optimization method is proposed. Firstly, the test results of a single sample under each stage of confining pressure are optimized by the method of fitting line, and the parameter a / b under each stage confining pressure is obtained. On this basis, the initial values of the parameter K _ (n) R _ f are calculated. Then based on Duncan Chang's theory, according to the obtained initial values of the parameters, the quadratic optimization of the whole set of test results is carried out, and the minimum sum of the square of the difference between the stress-strain curve calculated theoretically and the test is taken as the objective function. The main parameters of EB model are obtained. The method is simple and practical and can obtain the Duncan-Zhang model parameters quickly and accurately. The method is verified by combining with the triaxial test data of the Nuozhadu dam rockfill.
【作者单位】： 北京交通大学土建学院;
【分类号】：TV41
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本文编号：1825384