【作者】 张传庆；

【导师】 冯夏庭；

【作者基本信息】 中国科学院研究生院（武汉岩土力学研究所） ， 岩土工程， 2006， 博士

【摘要】 地下工程围岩安全性评价是工程设计和施工中安全控制的关键因素,它对于可研和设计阶段整体方案的规划、施工过程中开挖和支护方案的制定具有重要的指导意义。岩石工程安全性评价一般包括整体和局部两个层面上的研究内容,且这两个方面相互关联,前人已就此问题取得了很丰富的研究成果,但目前,在这两个层面上的研究仍存在一些问题尚未很好的解决:在围岩安全性局部评价层面上仍缺乏既有严密的力学基础又能将围岩进行全面安全分区评价的科学实用方法,对于如何评价复杂应力状态下围岩的应力集中程度,如何评价集中应力作用下围岩的损伤程度,如何准确地描述开挖过程中围岩安全状态的演化规律,如何评价非均质性对围岩安全性的影响等等问题,仍有待深入研究;而在整体安全评价层面上,整体安全性仍缺乏明确的工程意义,且与之相关的评价方法也有待系统研究。针对上述问题,本文在弹塑性力学和非线性系统动力学分析的基础上,通过分析岩石单元的应力危险性和应变损伤程度,提出了破坏接近度的概念,来进行岩石工程局部层面上的安全性评价;并在此基础上,通过分析岩石工程系统的耗散结构特征和自组织协同演化特征,建立了岩石工程整体系统的安全性评价方法;本文在大型岩土工程数值分析软件FLAC3D中开发了相应的分析模块,并结合实际工程算例验证了所建议方法的可行性和合理性。具体来说,本文主要完成了如下的研究工作:(1)在分析开挖过程中围岩安全性分区及其演化规律的基础上,通过分析主应力空间中一点应力状态与屈服面的相对关系,论文提出了屈服接近度的指标,通过分析塑性主应变空间的塑性剪应变的发展规律,论文提出了破坏度的指标,继而本文将二者合为一个表达变量,称为破坏接近度指标。通过多个算例的应用分析表明,利用围岩中的破坏接近度分布场,可给出围岩塑性区的范围,应力集中程度的分区,可合理地表达复杂应力状态下单元的应力危险性,还可以描述开挖损伤区内围岩的损伤程度,使得应力危险性和应变损伤程度的定量评价简单易行。另外,破坏接近度可以预估未来的开挖扰动所引起的破坏接近度特别是开挖损伤区、破坏区及扰动区发展范围及方向的变化,为工程施工中评判开挖扰动的影响,预估各区域未来发展的深度、方向提供依据。更多还原

【Abstract】 Safty evaluation of surrounding rockmass is the key factor in the design and construction of rock engineering. It is of great significance to plan the scheme of the whole project in the stage of argumentation and program the excavation and providing method in the stage of construction. But now, at the local level, it is still of vital problem to be solved how to put forward a new scientific and practical method to accurately estimate the stress concentration degree of element in rockmass, to evaluate its damage degree, and to describe the evolution rule of the stability state. And at the same time, the concept of safety at the entire level is not clear in the engineering. And the corresponding evaluation method needs to be developed. In order to solve the problems put forward above, a new concept named FAI (failure approach index) and the corresponding evaluation method is proposed in this paper.The main study works and results are listed as follows:1. Based on the analysis of the relation between a stress point and the yield surface in the principle stress space, an index named YAI (yield approach index) is proposed in this paper. Furthermore, the other index named FD (failure degree) is put forward to describe the damage degree of surrounding rockmass based on the rule analysis of evolution of the plastic shear strain in the principle plastic strain space. So a new variable called FAI (failure approach index) can be attained based on the function of YAI and FD. Some cases are presented and the results indicate that the FAI field in surrounding rockmass can supply many important information for the safety assessment such as the range of plastic field, the stress concentration degree of every element under the complex stress state, the damage degree of every element in the excavation damage zone, and etc. And by analyzing the evaluation rule of FAI in the process of excavation, we can forecast the variation of extent and depth of the excavation disturbed zone, damage zone and failure zone in the process of excavation.2. In order to study the heterogeneous effect on the safety of surrounding rockmass, this paper suppose that the risk parameterω, which is the phase complementary parameter of YAI is the a stochastic variable in this paper which conforms to the Weibull’s distribution and develops a new stochastic analysis method on safety of surrounding rockmass. An analyzing case is carried out. The application更多还原