【作者】 彭文轩；

【导师】 刘东燕；

【作者基本信息】 重庆大学 ， 岩土工程， 2004， 博士

【摘要】 本文研究了加锚状态下岩土体的稳定可靠度。鉴于常规岩土体稳定分析方法,如条分法、极限平衡法等,都建立在大量的假设与简化的基础上,同时,根据对锚杆机理的研究,锚杆对滑移体的最终锚固作用表现为改变滑移面的应力和应变状态,对于锚杆支护状态下的岩土体,如果从应力、应变角度分析锚杆对滑体的锚固作用,预应力锚杆主要起着提供轴向的附加应力的作用,而非预应力锚杆对滑体的锚固作用主要表现为提供轴向的应变约束。这样预应力锚杆和非预应力锚杆的极限状态函数将大为不同,由此确定的整个支护岩体的可靠度也将不同。所以根据常规确定性理论确定的极限状态函数并不准确;数值分析虽然计算结果比较准确,但必须经过很繁琐的计算过程,直接应用到可靠度分析并不理想。因此,本文研究的重点是确定更合理的加锚岩土体稳定计算模型,该模型必须更加准确地模拟加锚状态下岩土体的应力应变特征,必须能保证岩土体与锚杆之间的变形协调,必须全面反映锚杆的预应力状态或非预应力状态对可靠度指标的影响,另一方面必须更简便,便于可靠度分析与计算。 (1) 本文将锚杆作为一个单独力学体进行了承载可靠度研究,并将锚杆的承载可靠度指标分为设计阶段和施工阶段的可靠度指标。对于锚杆在设计阶段的承载可靠度研究,本文首先从承载状态与破坏过程的角度分析了锚杆的锚固力学机理,研究的重点在于模拟锚杆内锚固段各接触界面的应力传递、局部破坏与相对滑移,为此构造了一个非线性接触模型,并在此基础上对锚杆锚固段进行数值分析,从承载状态与破坏过程的角度分析了锚杆的力学机理,根据分析结果,分别对土层锚杆和岩层锚杆提出了确定锚杆承载能力的计算方法,并在此基础上建立分析锚杆承载可靠度的状态函数,对具体工程实例进行了可靠度计算;对施工后使用阶段锚杆的承载可靠度,本文在现场测试数据分析的基础上,针对测试样本较少的实际情况,引入随机-模糊理论和有限比较K-S(Kolmoglov)检验法建立了确定锚杆承载能力的数学概率模型。(2) 对加锚土体,考虑到稳定分析的极限平衡方式在模拟加锚土体稳定分析在理论上的不足:①无法模拟土体荷载与支护变位之间的关系,②无法模拟土体变位与锚杆支护力之间的关系,本文确定了一个综合极限分析理论、条分法、分块极限平衡法理论的稳定计算模型。该模型能将土体可能的滑移与破坏模式、锚杆的延伸及支护结构体的变位相互协调,通过鲍威尔(Powell)法优化搜索加锚土体极限状态下的可靠度指标。根据与Sarma法和库仑理论的拟合分析,本文建立的模型能更合理模拟加锚土体的应力-应变模式,同时也能比较方便地模拟分层土I<WP=6>中文摘要(3) 对加锚岩体,本文将岩体分成存在明显滑移面和存在断续结构面的岩体分别进行分析,对加锚状态存在明显连续滑移面的岩体,本文首先研究了这种类型岩体的力学形态,指出常规确定性分析模型不能合理模拟岩体结构面的应力不均匀分布及滑移面破坏的渐变状态。在此基础上,根据最小势能原理,确定了一个综合考虑滑面位移、滑面局部渐变破坏及滑面位移与锚杆锚固力协调的可靠度分析模型。对加锚状态含断续结构面的岩体,本文并没有构筑新的力学计算模型,而是在常规模型基础上进行了适当调整进行可靠度计算,分析了加锚状态对岩体稳定可靠度指标的影响。(4) 由于在加锚状态下,岩土体是一个整体体系,岩土体的失稳包括岩土体自身的破坏与失稳,也包括锚杆的破坏,本文提出了“可靠度阀值”的概念,用来进一步分析加锚岩土体的渐进性的破坏方式、及稳定储备。 (5) 采用Ditlevsen 方法,分析了多种破坏模式下,破坏模式之间的相关性,及其对加锚岩土体的整体稳定可靠度的影响。更多还原

【Abstract】 This paper research stability reliable degree of the rock mass and soil mass underanchor state. Seeing that routine stabilizes analytical method, for instance " the dividelaws", " limit balanced law"etc., Set upa on the basis of a large amount of assumption andsimplifying, besides, at study on mechanism, finally anchor function of anchor is tochange stress and strain state of the slippery body. To anchored rock and soil mass, ifanalyses anchor effect on the angle of stress and strain state, The anchor under prestressplays a role in offering the additional stress of the axial mainly, The main function of theanchor under un-prestress is to offer axial retraining on the slippery body. In this way,limit state function of the anchor under prestress and the one under un-prestress is verydifferent, This determines reliable degree of anchored body is entirely different too. Sothe limit state function that determines according to the determinacy theory of the routineis inaccurate; Though the result of FEM analyses is relatively accurate, but must bethrough very many and miscellaneous with trifles computational process, it isunsatisfactorily to use directly to reliable degree analysis. So, the focal points of researchin the paper is to determine rational steadily calculate model of anchored mass and soilmass. This model must accurately simulation the stresses and strain state characteristic ofanchored rock mass and soil mass, must be could guarantee displacement coordinatebetween rock & soil mass and anchor, must be could reflect the state of prestress andun-prestress impacting on reliable degree, on the other hand, must be simple and moreconvenient benefit to analysis and calculate reliable degree. (1) As an alone mechanics body,mechanism the reliable degree of anchor isanalyzed in this paper, the reliable degree of anchor is divided into design phase andconstructs stage. To the research ofreliable degree ofdesign phase, mechanism of anchorisanalyzed by theplasticity theory andthe finite element method, new type state functionisdefined. To the research ofreliable degree of constructs stage, on the basis of testing thedata analysis at the scene, set up the probability model of mathematics, rationallydetermine the reliable degree ofanchor. (2) To anchored soil mass, considering the deficiency in theory of limit balancedways:⑴Unable to imitate the relations of load on soil and anchor’s displacement;⑵Unable to imitate the relations of anchor’s strength and soil’s displacement, This thesis III<WP=8>英文摘要determine a stability calculate model synthesizing limit theory of analysis, dividing law,limit balanced law , This model coordinate the possible move and destroy of soil mass,the extensions of stock anchor, Through optimizing and change and take the place, canrational simulations the emergency stress mode of anchored soil mass, can carry onrelevant conveniently calculating reliable degree, at the same time, it can simulationlayers of soil mass and the state of prestress impactingon reliable degree. (3) To anchored rock mass, this thesis analyze separately by dividing the rock massinto the ones with obviously move face and the one with intermittent structure face. Tothe rock mass with obviously move face, the mechanics is studied firstly, and this textpoints out routine analyses model can’t rational simulation even distribution of stress andgradually destroying state on contact surface. On the basis of this, according to theminimum principle of potential energy, determine reliable degrees analysis models withsynthetically considering sliding surface displacement, sliding surface graduallydestroying, and coordinating between sliding surface displacement and anchor strength.To anchored rock mass with intermittent structure face, this paper adjust reliable degreeto calculate properly on the basis of routine model, Have analyzed the state of the anchorimpactingon rock body steady reli更多还原