岩石工程稳定性控制参数的直觉分析

基于BP神经网络，定义了衡量网络输入对输出作用大小的相对作用强度RSE（RelativeStrengthofEffect），并结合实际的岩石工程实例数据用RSE分析了其各个作用参数对工程稳定性的影响的相对大小与作用方式。实际分析的结果表明，所提出的方法能够较全面地反映岩石工程现场的复杂实际情况，具有易于处理不确定性、动态与非线性问题等优点，是对岩石工程进行参数分析的有效工具。     

围岩——支护作用机制评述及其流变变形机制概念模型的建立与分析

岩石地下工程支护理论的核心问题是围岩-支护相互作用机制.首先,分析卡斯特纳方程和围岩-支护作用机制存在的缺陷和错误,包括:(1)模型对支护反力的产生及其支护时机、加载路径等力学处理不具有工程实际意义.(2)由卡氏方程和弹塑性公式推导的围岩特性曲线在工程实际中不存在,因此也不存在与支护结构的支护特性曲线相交的可能性.(3)将围岩特性曲线和支护特性曲线相交求解围岩-支护相互作用的平衡点存在概念及逻辑上的错误.然后,建立基于流变变形的围岩-支护相互作用机制的概念模型.最后,应用流变机制概念模型对工程实例进行计算,推演围岩与支护的相互作用过程,从理论上证实混凝土结构在一定条件下支护软岩巷道是可以的.提出的流变机制概念模型,既可以对围岩-支护相互作用给出定性解释,也可以应用于岩石地下工程的设计,理论基础可靠,能够应用于工程实践.     

锚固设计的关键机理路径分析法及实例分析

本文针对地下工程难支护问题，基于岩石工程系统（RES）理论中的关键机理路径分析法，提出了一种锚固设计的理念。然后在结合实例的基础之上，根据各因素之间的关系建立了二元交互作用矩阵；并应用关键机理路径分析算法进行耦合过程获得了关键路径收益值和反馈回路，第一次提出了良性循环作用路径这一概念。最后，针对某矿区一采准巷道确定了主要承载区和支护参数。数值分析和监测数据表明，支护达到预定的效果。     

基于MATLAB的ANN方法在桩基岩石强度预测中的应用

人工挖孔灌注桩广泛应用于工业与民用建筑、桥梁、港口、码头等工程建设领域,对于高层建筑,此种方法应用的更为普遍。桩基岩石强度直接决定工程质量和安全。利用MATLAB软件提供的改进人工神经网络算法,调用PRESTD、POSTSTD、POSTREG函数进行样本处理和网络结果分析,建立数学分析模型。并且结合工程实例,对桩基岩石抗压强度进行预测。将预测结果与室内实验得到的抗压强度值及回归分析的预测值比较,得到良好的预测精度,有一定的实际应用价值。     

基于MATLAB的ANN方法在桩基岩石强度预测中的应用

人工挖孔灌注桩广泛应用于工业与民用建筑、桥梁、港口、码头等工程建设领域，对于高层建筑，此种方法应用的更为普遍。桩基岩石强度直接决定工程质量和安全。利用MATLAB软件提供的改进人工神经网络算法。调用PRESTD、POSTSD、POSTREG函数进行样本处理和网络结果分析，建立数学分析模型。并且结合工程实例，对桩基岩石抗压强度进行预测。将预测结果与室内实验得到的抗压强度值及回归分析的预测值比较，得到良好的预测精度，有一定的实际应用价值。     

基于时间效应的反演分析方法在深基坑工程中的应用

基于时间效应模型,将有限元数值方法与优化方法相结合,建立了动态施工反演分析方法,对土体、支护结构、支撑体系、支护与土体相互作用以及基坑动态施工过程进行了模拟,以达到对基坑支护结构变形作出动态预报的目的,并结合现场测试,应用动态施工反演分析方法,对南京市黄埔广场2期基坑支护工程进行了施工效果分析.     

围岩–支护作用机制评述及其流变变形机制 概念模型的建立与分析

 岩石地下工程支护理论的核心问题是围岩–支护相互作用机制。首先,分析卡斯特纳方程和围岩–支护作用机制存在的缺陷和错误,包括：(1) 模型对支护反力的产生及其支护时机、加载路径等力学处理不具有工程实际意义。(2) 由卡氏方程和弹塑性公式推导的围岩特性曲线在工程实际中不存在,因此也不存在与支护结构的支护特性曲线相交的可能性。(3) 将围岩特性曲线和支护特性曲线相交求解围岩–支护相互作用的平衡点存在概念及逻辑上的错误。然后,建立基于流变变形的围岩–支护相互作用机制的概念模型。最后,应用流变机制概念模型对工程实例进行计算,推演围岩与支护的相互作用过程,从理论上证实混凝土结构在一定条件下支护软岩巷道是可以的。提出的流变机制概念模型,既可以对围岩–支护相互作用给出定性解释,也可以应用于岩石地下工程的设计,理论基础可靠,能够应用于工程实践。     

第7届全国岩石动力学学术会议征文通知(第1号)

中国岩石力学与工程学会岩石动力学专业委员会拟定于2001年8月在东北地区召开“第7届全国岩石动力学学术会议”,欢迎全国相关学科的专家、学者、科技工作者与工程技术人员踊跃向会议投稿。征文内容:(1)岩石动力学学科发展回顾与展望;(2)岩石动态力学性质与本构关系;(3)岩石和岩体中应力波的传播与衰减规律;(4)岩石动态断裂机理与数值模拟;(5)岩石动力学与防护工程;(6)岩石爆破与控爆技术;(7)岩爆与冲击地压机理研究;(8)岩石动力参数的测试技术与方法研究;(9)应力波理论在桩基工程中的应用;(10)其他与岩石动力学相关问题的研究。提交会议论文…     

基于贝叶斯判别法的工程岩爆危险评估与预测

基于岩爆在工程中的特点和岩爆烈度分级预测理论,运用贝叶斯判别原理,确定了工程岩爆危险评估与预测的贝叶斯判别分析法。通过辨别对岩爆产生作用的因子,拣选了围岩最大切向地应力/岩石单轴抗压强度(σθ/σc),岩石单轴抗压强度/岩石单轴抗拉强度(σθ/σt),弹性能量指数(Wet)作为贝叶斯判别分析模型的判别因子,从而进行岩爆误判概率的计算与岩爆危险评估与预测。以贵州省江口至都格、江口至瓮安高速、杭瑞高速等公路工程实例作为学习样本,进行训练判别,通过与现场观测、聚类分析、人工神经网络方法(NN)的预测进行对比,结果发现与训练模型回判的结果一致,验证了贝叶斯判别准则的可行性与可靠性,其对岩爆危险的准确分级和预测,具有较高的工程应用价值。     

模糊综合评价在水环境质量评价中的应用

在水环境质量的评价过程中,通常涉及到大量的复杂现象和多种因素的相互作用,评价中存在大量的模糊现象和模糊概念.介绍了模糊综合评价法的原理及其评价方法,同时将人工神经网络引入模糊综合评价隶属矩阵的确定过程,利用人工神经网络构造隶属函数矩阵,并以青岛大沽河为例,利用模糊综合评价法对其水质进行了评价,并取得了良好的评价效果.     

The application of neural networks to rock engineering systems (RES)

This paper proposes a new approach for applying neural networks in Rock Engineering Systems (RES) based on the learning abilities of neural networks. By considering the analysis of the coding methods for the interaction matrix in RES and the learning processes of neural networks such as the Back Propagation (BP) method, neural networks can provide a useful mapping from system inputs to system outputs for rock engineering, so that the influence of inputs on outputs can be obtained. Then the results of the neural network analysis can be presented in a similar way to the global interaction matrix used in RES to present the fully-coupled system results. The neural network procedures are explained first, with illustrative demonstrations for simultaneous equations. Then, the link with the RES type of analysis is explained, together with some demonstration examples for rock engineering data sets. The specific analysis procedure is presented and then wider rock engineering examples are given relating to the characteristics of rock masses and engineering parameters. The main presentation tools used in this neural network approach are the Relative Strength Effect (RSE) and the Global Relative Strength Effect (GRSE) matrix. There is discussion of the value of this approach and an indication of the likely areas of future development.     

Evaluation model of surrounding rock stability based on fuzzy rock engineering systems (RES)-connection cloud

The factors affecting the stability of surrounding rock have fuzzy randomness, and their evaluation indicators not only show boundary ambiguity and interval discreteness but also have complex interactions. In order to reflect the distribution characteristics and interaction relationship of the indicators, and improve the accuracy of surrounding rock stability evaluation, a stability evaluation model of surrounding rock based on a fuzzy Rock Engineering Systems (RES)-connection cloud is proposed. The research showed that the introduction of linguistic hesitant fuzzy sets improves RES, resulting in experts’ compilation completely retained. Through cloud theory transformation, the subjectivity can be further weakened, and the credibility of indicator weight can be effectively improved. The two-dimensional cloud cause-effect map can reflect the indicator interaction relationship more intuitively and accurately. The joint state is found to be the most dominant parameter, and groundwater seepage is found to be the least dominant parameter. Furthermore, the connection cloud can overcome the defects of traditional cloud model which assumes the indictor follow normal distribution. Comparing the engineering application results with the matter-element extension method and the fuzzy set method, the feasibility of the present model is verified.

     

求解非均匀无限地基相互作用力的有限元时域阻尼抽取法

由于无限地基的动力效应较难确定,结构-地基的动力相互作用主要局限于频域分析,从而限制了非线性分析应用。阻尼抽取法(DSEM)通过在有限域内施以附加人工阻尼再移频抽取的办法可以有效地模拟非均匀无限粘弹性介质的动力特性,在结构-无限地基动力相互作用分析中有较好的应用前景。在此基础上,本文提出了DSEM进行结构-地基交界面相互作用力-位移时域分析的有限元逐步积分形式算法,并给出了具体实现公式,可以更好地适应工程有限元计算及与结构-地基相互作用程序结合的需要。最后,以实例形式论述了该方法良好的精度及实现中各个关键因素的影响。     

钢结构稳定设计——理论与实践

本文提出了实际工程结构的非线性理论设计和分析方法(NIDA),并以澳门回归纪念馆的设计为例,展示了本方法的优越性.在设计过程中,设计者无需假设K系数和有效长度,在结构分析完成后便可迅速完成设计,因此本文提出的方法既经济又便利.尽管对于钢框架在往复荷载及动力荷载作用下的弹塑性大位移分析已经非常成熟,但本文的方法开创了结构的非线性分析及设计的新纪元,能够对现行的设计方法理论起到巨大的推动作用.     

Retrospective case example using a comprehensive suitability index (CSI) for siting the Shisan-Ling power station, China

The purpose of this paper is to present a retrospective case example of using the rock engineering systems (RES) methodology to site a pumped storage power station in China. With such a siting problem, there are many interacting factors governing both the site and the specific underground position of the powerhouse. The RES approach, based on an interaction matrix for semi-quantitative characterization of the factors and their interactions, is used to develop a comprehensive suitability index (CSI). In this way, the factors governing the geological and rock mechanics related factors are structured and evaluated. Additionally, the complexity of the decision making process is condensed to the CSI values for different potential sites and underground locations, a higher CSI value indicating a more suitable site.The retrospective analysis uses information from the investigations made during the actual site investigation and design work for the Shisan-Ling Power Station, China — which has been constructed. For the first stage, site selection for the overall engineering arrangement, 11 parameters concerned with geology, geomorphology, engineering layout, environment, cost and construction are taken into account. After comparison of site options in conglomerate, andesite and limestone formations, the conglomerate formation proved to be most favorable — because it has the highest CSI value. For the second stage, specifically locating the underground powerhouse, another seven parameters associated with faults, joints, groundwater, etc. are evaluated. As a result, position II proved to be the most favorable location for the powerhouse. Since these were the same conclusions reached during the actual investigations, this retrospective application of the CSI demonstrates the value of the RES methodology and associated indices for assisting in rock engineering design.     

Sequential parametric identification and response of hysteretic oscillators with random excitation

Sequential methods are developed for estimating the parameters in a differential model of a curvilinear class of hysteretic force characteristics. In the case where the hysteretic force is directly observable it is shown that the hysteretic “loop” parameters may be identified by using either a two-stage linear estimation method or a one-stage method, based on a sequential non-linear filter. For oscillators with a non-observable hysteretic force it is demonstrated that the non-linear filtering approach can be extended to allow estimation of all the relevant system parameters, including the oscillator mass. The proposed methods are validated y application to both simulated and real experimental data. The latter was acquired during dynamic tests on a stranded steel cable, undergoing both sinusoidal and random flexural vibrations. Using identified parameters, good agreement between theoretical and experimental response statistics is obtained, in the case of random excitation.     

Spatial comparison of renewable energy supply and energy demand for low-carbon settlements

Cities are responsible for a large part of primary energy demand and emissions worldwide. Hence, the use of renewable energy sources (RES) is becoming a key issue in the international debate on the sustainability of urban development models. Most of the literature addresses this issue by focusing on metropolitan areas, disregarding analyses that can support urban design at smaller scales. This paper presents and applies a method to estimate and compare the potential supply of RES and the energy demand of buildings (EDB) at local scale by: (a) performing a spatial estimation of the potential exploitation of RES; (b) performing a spatial estimation of EDB, by considering their characteristics and location, as well as the urban morphology and the settlement design; (c) assessing the spatial congruence between supply and demand patterns. Four RES were analyzed: solar irradiation, ground-source heat, wood biomass and hydropower from existing drinking water supply systems. Suitability maps for each energy source were first developed, and then combined to obtain a composite map, which was eventually compared with the EDB map. The method is based on spatial and statistical analyses conducted in a geographical information system (GIS), using data layers coming from a range of different sources. The case application is represented by an alpine municipality in Trentino, northern Italy. Even though the proposed approach is affected by uncertainties and data scarcity, it showed how datasets and tools available today can be used to provide spatial estimates of RES suitability for exploitation, supporting the selection of areas that are intrinsically suitable for the design of low-carbon settlements.     

Pile-soil-structure interaction in pushover analysis of jacket offshore platforms using fiber elements

In this paper, pushover analysis of fixed jacket offshore platforms with the application of “Fiber Elements” which are capable of modeling post-buckling behavior of braces has been conducted and case study on two functional jacket offshore platforms in the Persian Gulf region has been performed. Two-dimensional models of the mentioned platforms are simulated using “DRAIN-3DX” software and the wave force is considered as the lateral load pattern on the structures.In this paper, pushover analysis of jacket offshore platforms is performed by developing numerical models that incorporate different foundation conditions for considering pile-soil-structure interaction. Increasing the displacement of the platforms and recording the relative load factors by incorporating the displacement control method is the basis for performing the analysis. In order to consider the importance of pile-soil interaction, six individual cases are examined which include pile-soil interaction analysis with actual soil in-situ characteristics. Pile head fixed below mud line elevation, pile head hinged below mud line elevation, application of linear pile stubs, application of non-linear pile-stubs & finally a combination of linear and non-linear pile-soil characteristics.In the analyses performed herein, the condition in which pile-soil interaction is considered is set to be the base case. The results from incorporating the non-linear pile stub have the most compatibility with the base case. Application of Linear pile stubs and the combination of linear and non-linear pile has much deviation with the base case. Ultimate strength of the platform in the non-linear pile stub case was very close to the base case.