缓冲材料试验台架热-水-力耦合数值模拟研究
Numerical thermo-hydro-mechanical modeling of buffer material in mock-up test for deep geological disposal
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摘要: 在高放废物深地质处置中,缓冲材料是最后一道人工屏障,研究其在热-水-力多场耦合作用下的长期性能对处置库的稳定运行至关重要。基于热-水-力耦合基本理论,针对缓冲材料试验台架,开展了高庙子膨润土在多场耦合条件下的长期性能数值模拟研究。文章首先对高庙子膨润土的基本物理力学性能进行介绍,随后建立了热-水-力多场耦合数值模型。该模型考虑了热、水在非饱和土中的传播,其中,Alonso-Gens的BBM模型被用于描述缓冲材料膨润土在非饱和条件下的力学性能。最后,采用LAGAMINE多场耦合数值软件,对缓冲材料膨润土在热-水-力多场耦合条件下的长期性能进行数值分析。分析结果表明,本数值方法可以很好的描述缓冲材料膨润土在多场耦合条件下的力学性能和水、热传播规律。Abstract: Bufffer material is the last artificial engineered barriers for the repository in deep geological disposal of high-level radioactive waste.It is necessary to demonstrate the long term properties of the buffer material under coupled thermo-hydro-mechanical conditions after the repository closed.A numerical study of the test is conducted in this paper.The principal THM characteristics of the bentonite are present at first.A THM model is then present to tackle the complex coupling behaviors encountered in the bentonite.A detailed formulation coupling heat,moisture in unsaturated soil is given.The formulation of Alonso-Gens mechanical model for unsaturated soil is incorporated to reproduce the mechanical behavior of the bentonite.Finally,with the proposed model,numerical simulations of the mock-up test are carried out by using the code of LAGAMINE.The time variations associated with the temperature,degree of saturation,suction and swelling pressure of the compacted bentonite are studied.The results suggest that the proposed model is able to reproduce the mechanical behavior of the bentonite,and to predict heat,moisture motion under coupled THM conditions.
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