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Research on progressive failure and the establishment of analytical method based on constitutive

基于本构的渐进失效研究及分析方法建立

基本信息

批准号：
04452226
负责人：
ADACHI Toshihisa
金额：
$ 4.29万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

1.The derivation of elasto-viscoplastic model with strain-softeningBased on Adachi-Oka's model with strain softening, and elasto-viscoplastic model which can both describe the time dependency and strain-softening, is proposed for soft rock. In the derivation of the model, three new assumption are adopted. That is, the new definition of stress history, the introduction of time measure and the decline of shearing strength with time.2.Investigation of the validity of the proposed elasto-viscoplastic modelThe time dependent behavior includes three aspects as strain rate dependency, creep and stress relaxation. The proposed model is applied to the drained triaxial shearing tests of Ohya-stone and the drained triaxial creep tests of Ohya-stone. It is found that the model can well simulate the all aspects of time dependent behavior.3.Analysis of progressive failure on model groundBased on above mentioned model, a finite element analysis of progressive failure on model ground is carried out. As a result, the mechanism of progressive failure that occurs at first in local point and develops to other place progressively is well simulated. The validity of the model in boundary problems is proved.4.Finite element analysis of progressive failure on soft-rock-slope excavationBy considering the strain-softening, the deterioration of strength with time and the initial k_0-stress state in the ground, a finite element analysis of elasto-plasticity is carried out for the excavation on slope to investigate the progressive failure caused by slope excavation. As a result, it is found that the ground yields progressively with the deterioration and the stress in the ground redistributed with deformation.

1.在Adachi-Oka应变软化模型的基础上，提出了既能描述时间依赖性又能描述应变软化的软岩弹粘塑性模型。在模型的推导中，采用了三个新的假设。即重新定义应力历史，引入时间度量和抗剪强度随时间递减规律。弹粘塑性模型的有效性研究弹粘塑性模型的时间依赖行为包括应变速率依赖、蠕变和应力松弛三个方面。将该模型应用于Ohya-stone排水三轴剪切试验和排水三轴蠕变试验。结果表明，该模型能很好地模拟随时间变化的行为的各个方面。基于上述模型，对模型地基的渐进破坏进行了有限元分析。从而较好地模拟了从局部开始，逐渐向其他地方发展的渐进式破坏机理。证明了该模型在边界问题中的有效性。软岩边坡开挖累进破坏的有限元分析考虑边坡的应变软化、强度随时间的劣化以及地基初始k_0应力状态，对边坡开挖进行弹塑性有限元分析，研究边坡开挖引起的累进破坏。结果表明，随着地基的恶化，地基逐渐屈服，应力随变形而重新分布。