锚杆支护顶板失稳的突变理论浅析

应用突变理论来研究采用场锚杆支护顶板围岩失稳的力学过程,分析研究了锚杆支护系统发生突变的突变尖点。     

某铜钼露天矿边坡失稳影响因素分析及治理对策

露天矿边坡的稳定是矿山安全生产的保证.某铜钼露天矿东侧边坡690 m台阶面上已形成一个长52 m的塌陷坑,690～678 m台阶花岗斑岩和长英质角岩较破碎,坡面风化较严重,发生坍塌滑坡,影响矿山正常的采矿进程和采场内作业人员的安全.通过分析该矿边坡失稳影响因素及治理对策,指出边坡失稳破坏是多种因素共同作用的结果,并提出...     

事故树分析法在露天边坡稳定性分析中的应用

为对露天边坡稳定性进行科学合理的评价分析,在综合分析露天边坡失稳事故的基础上,采用安全系统工程中的事故树分析法,建立了露天边坡失稳事故树模型。通过计算事故树的最小割集、最小径集和基本事件的结构重要度,找出了导致露天边坡失稳的主要因素,即边坡支护和边坡监测。事故树分析法能够对导致露天边坡失稳的各种因素及逻辑关系作出全面的阐述,并根据结构重要度提出针对性的防治措施,为露天边坡的安全管理提供可靠的参考依据。     

露天矿山边坡失稳事故树分析

以洪水塘灰岩矿边坡失稳为研究对象,利用安全检查表分析法(SCL)和预先危险性分析法(PHA)辨识了其边坡失稳的危险源,通过事故树罗列了边坡失稳的影响因素,表明治理边坡失稳的手段应从技术和管理两方面共同考虑.分析了基本事件结构重要度,其中岩体物理力学性质降低影响最大,其次是布孔不当和钻孔超深,在该矿山做好地质勘探工作、测...     

考虑水平荷载的采空区群系统灾变失稳模型

为了研究采空区群系统的灾变失稳,将顶板简化为弹性薄板,矿柱简化为在长期荷载作用下会产生蠕变损伤的Poynting-Thomson体,考虑水平荷载和竖直荷载的共同作用,结合流变理论和燕尾突变建立采空区群顶板—矿柱系统灾变失稳模型。计算出模型突变时顶板中心的下沉量,矿柱有效支撑面积与顶板面积的比值,以及模型从开始到发生突变的时间,以广西盘龙铅锌矿为工程实例进行验证,得出盘龙矿采空区群系统的稳定时间与实际情况相符,验证了该模型的可靠性和实用性。同时,研究了各影响因素对采空区群系统稳定性的影响,为采空区群系统稳定性分析提供了新思路和新方法。     

关键块体系统锚固法在加固边坡危岩中的应用

基于Goodman-Shi的块体理论和A.R.Yarahmadi Bafg hi的关键块体群理论,提出确定危岩边坡关键块体和关键块体系统的几何分析法和矢量分析法,建立边坡危岩的地质模型和力学模型,分析危岩体破坏机理,针对不同变形破坏机理的关键块体系统提出合理、安全和经济的危岩边坡加固新方法--关键块体系统锚固法(KSA法).通过建立集丹公路K49+790 m-K55+550 m段危岩边坡的地质模型和力学模型,结合其坡体及岩体结构特征,分析边坡危岩体变形破坏机理和锚固机理,提出顶部危岩清除,碎裂结构坡面喷射混凝土,块裂结构坡面挂网和块状岩体锚固的清-喷-网-锚联合锚固的系统锚固方案,加固该段危岩体.运用该法锚固方案较传统方法节省锚杆35%、SNS网32%及腰梁19%.     

露天矿山边坡稳定治理与生态修复技术分析

露天矿山开采活动会形成采场边坡,受地质岩体结构、自然环境以及工程活动等因素的影响,极易出现失稳并引发地质灾害,对周边自然环境造成严重破坏。露天矿山边坡失稳不仅会造成经济损失,还会造成安全事故。本文从地质灾害治理和生态修复角度,分析露天矿山边坡失稳的影响因素,并探讨边坡稳定化及生态修复技术,为矿山地质生态环境治理提供借鉴和参考。     

岩土工程中边坡加固工程施工技术探索

<正>影响边坡失稳的因素较多,想要对边坡加固施工技术进行研究,就需要先对其影响因素及失稳原因进行讨论,并加以解决。一般来说,影响边坡稳定性的因素有四个：地质环境、岩土结构质量、人为因素和其他因素。针对边坡失稳的情况,本文主要分析其影响因素,并选择合理的加固工艺,确保边坡的稳定性。一、影响边坡稳定性的因素(一)岩土结构质量在施工领域,能够影响岩土结构质量的因素有两个,分别是结构面和结构体。其中,结构面指的是岩土的不连续面和分异面,     

基于物探技术的露天矿边坡失稳因素勘测研究

为查明工程地质条件和气象水文条件对软弱结构面形成的影响,准确定位软弱面的位置,分析软弱面在边坡失稳过程中的作用,采用高密度电法和地质雷达法综合物探技术对露天矿边坡失稳影响因素进行了勘测,并解释了勘测结果。采用物探技术对白云鄂博铁矿边坡进行探测,结果表明:高密度电法和地质雷达勘测方法利用边坡裂缝发育程度、物理性质与围岩的电阻率差异,进行了裂缝分布勘测;利用水导电性好、对电磁波吸收作用强的特点,进行了地下水勘测,将探测反演结果相互印证,结合钻孔数据和工程水文地质资料,进行研究区边坡失稳因素推测,能够有效提高软弱面定位的准确性,为边坡失稳灾害预测提供支持。     

边坡治理工程中岩土工程勘察的技术方法

边坡失稳是当前最常见的一种地质灾害,其危害程度也非常高,所以针对边坡问题开展一系列的治理工作是非常重要的,一旦发生边坡失稳就可能导致崩塌、滑坡以及泥石流灾害的发生,会对国家和人民的生命财产安全带来巨大的威胁。岩土勘察作为边坡治理的核心技术,能够对边坡进行全面的、综合的勘察,及时发现边坡中存在的灾害隐患,并采取一系列的防治措施,将灾害发生带来的影响降到最低,本文主要就是对边坡治理工程中岩土工程勘察技术手段的运用进行详细的分析。     

Clash of the paradigms: A critique of an examination of the polynomial regression technique for evaluating catastrophe theory hypotheses.

The polynomial regression technique for evaluating catastrophe theory hypotheses (S. J. Guastello; 1982, 1987, 1988) has met with criticism from R. A. Alexander et al (see record 1992-18389-001) regarding the specification of terms in the catastrophe model and the order in which they are entered, the role of part–whole correlations, and whether the polynomial regression technique is adequate for discerning the presence or absence of catastrophic structure. Their criticisms are unwarranted and misconceived because of inattention to some fundamental principles of mathematical catastrophe theory, misuse of the polynomial regression technique in their simulations, and an outmoded paradigm of scientific inquiry. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Catastrophe modeling of the accident process: Organizational subunit size.

Empirical findings and theory on record attempting to link accident rates with the size of organizational subunits are at best contradictory. In this study, I hypothesized that accident rates are cusp catastrophic in nature and that size acts as a bifurcation variable in the process. Units of analysis were 283 subgroups of a midwestern steel factory. Accident, severity, and size data were collected for four time horizons. I tested the cusp catastrophe hypothesis by using the method of polynomial regression, which permits direct hypothesis testing. R–2 coefficients for the cusp catastrophe ranged from .37 to .51, compared with .03 to .26 for the control models. This article is primarily an illustration of the polynomial regression technique for catastrophe theory hypotheses. The technique is used to solve an apparently intractible theoretical problem. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical, Mental, and Social Catastrophic Cognitions as Prognostic Factors in Cognitive-Behavioral and Pharmacological Treatments for Panic Disorder.

The authors explored the prognostic value of 3 different types of catastrophic cognitions in the treatment of panic disorder with and without mild-to-moderate agoraphobia using a sample of 143 participants who received either cognitive-behavioral therapy (CBT) or imipramine in a randomized controlled trial. Stronger fears of social catastrophes both prior to and following treatment with CBT or imipramine were associated with a poorer outcome. In contrast, cognitions involving physical or mental catastrophes were unrelated to outcome, regardless of whether these thoughts were measured prior to or following treatment. These findings are consistent with the notion that although the intensity of physical catastrophe cognitions may best discriminate between panic disorder and other anxiety disorders, it is the intensity of social catastrophe cognitions that is most closely tied to success in treating this disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mount Saint Helens's ashfall: Evidence for a disaster stress reaction.

The Mount St Helens's ashfall provided a natural setting for the study of stress reactions to catastrophic events. Pre- and postdisaster data were collected from formal records and reports of 12 local agencies to examine the effects of disaster-related stress on mental illness and social behavior. Postdisaster data indicated a substantial increase in illness, alcohol abuse, family stress, violence, and aggression, with related adjustment problems. Data suggest that a postdisaster stress reaction, which is relatively nontransient, can occur following a catastrophe. (68 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical Modeling of Compressive Behaviors of Anchored Rock Masses

The mechanical characteristics of rock masses anchored with bolts play a critical role in anchored slope and underground buildings. In this study, the components and their mixing ratios of similar materials, such as rock masses, are simulated. The materials similar to the anchored bolts and cement are selected. The physical and mechanic properties of these materials are tested. Based on these, an experimental model and a method are designed with a focus on a uniaxial compression test on anchored rock masses. A series of tests on the anchored specimens’ uniaxial compression strength are conducted under the conditions of varying numbers and installations of anchor bolts. The results reveal that compared with the specimens without anchor bolts, the peak strength, elastic modulus, and shear strength of the specimens with both perpendicular and horizontal bolts are improved. Furthermore, it is indicated that the improvement attributable to the horizontal bolts is slightly lower than that with vertical bolts. This suggests that the uniaxial compression strength is heterogeneous in different directions.     

基于变量选择的尖点突变模型的两步构建方法

突变是工程实践过程中广泛存在的现象.当系统的状态发生跳跃性变化时,基于微积分的传统数学建模方法精度较低,人工神经网络等机器学习算法无法对突变现象作出合理的解释.基于突变理论的尖点突变模型可以用来解释系统状态的不连续变化,然而在输入变量维度较大的情况下,传统的尖点突变模型复杂度高且精度较差.为了解决这一问题,提出了一种基于变量选择的尖点突变模型的两步构建方法.第一步,利用多模型集成重要变量选择算法(MEIVS)量化待选变量的重要性并提取重要变量;第二步,基于极大似然法(MLE)利用所提取的重要变量构建尖点突变模型.仿真结果表明,在具有突变特征的数据集上,通过MEIVS降维后的尖点突变模型在评价指标上优于线性模型、Logistic模型和通过其他方法降维的尖点突变模型,并且可以用来解释研究对象的不连续变化.     

应用突变理论优选矿井通风系统改造方案

突变理论优选法与其他方法相比,具有计算简单、客观性和实用性强等特点,是一种可以广泛应用于金属矿山矿井通风系统设计的科学方法。通过对某金属矿山矿井通风系统改造方案的优选研究,详细介绍了突变理论优选法的基本原理和具体步骤。研究针对该矿山拟定的技术改造方案,并根据网络解算结果,选取合适的评价指标,应用该方法进行方案分析和筛选,确定最佳的通风系统改造方案。