模糊集合论在岩体的综合评价和工程分类上的应用

岩体的工程分类是岩体力学的基本问题之一.岩体工程分类的主要目的是,针对不同的工程对象,对岩体进行综合评价,划分等级,区分成性质相近的类别,为工程的选点,设计提供定量的资料.同时,岩体的工程分类也是我们按不同的类型深入研究岩体的力学性质,建立相应的数学模型的基础.因此岩体的工程分类具有重要的实际意义,对它的研究日益广泛地引起了人们重视.到目前为止,已提出了不少岩体的分类法.从不同的出发点大体分为两类,(1)从岩体力学出发对岩体特性的一般性分类,例如Muller的分类等.(2)为特定的工程目的分类,例如为岩石边坡的Goodman分类法等.为隧道工程而提出的岩体分类最早是Terzaghi(1946年)的分类法.后来还有Lauffer(1958年)等人提出的分类法.     

基于RMR的模糊AHP法在岩体分级中的应用

传统的RMR法采用固定评估因素、固定评分方式进行岩体分级,其评分过程中存在着许多不确定性和主观性,在地质条件复杂的情况下岩体分级效果差.为了改变RMR法存在的不足,本文在参考RMR法的基础之上,提出了将AHP法应用于岩体分级的方案,给出了模型计算流程.将岩体分级看作一个多属性决策问题,根据实际情况可随机加入或减少影响岩...     

边坡岩体质量分级的模糊层次分析

边坡岩体质量分级是一个涉及到水文地质、工程地质、开挖条件、岩石力学等诸多因素的复杂地质问题。本文把模糊层次分析法综合应用于边坡岩体质量分级,利用层次分析法划分影响边坡岩体质量各因素的层次结构,用模糊分析法来确定各因素的权重。同时建立了与之相适应的各因素评分准则与边坡岩体质量评分准则。按照研究的成果,对一个具体实例进行了分析并与其他方法进行对比,验证的成果有效性,拓展了岩体质量分级理论的研究思路。     

地下工程围岩分类模糊推理系统设计

将现场获取的影响地下工程围岩分类的几种主要因素视为判别围岩类别论域上的模糊子集,利用建立的地下工程围岩分类模糊逻辑推理系统对围岩类别进行模糊逻辑推理运算,获得与实际情况相一致的围岩类别的判定,直接为地下工程的信息化设计和施工提供依据。     

应用力学机理的网络模拟预测隧洞超挖问题

概述了结构面的网络模拟技术的基本原理、方法和现状。在充分考虑岩石破裂的力学机理的基础上,结合野外测得的结构面特征参数,提出了一种基于力学机理分析的网络模拟技术,并把该技术运用到地下洞室的超挖预测中。通过某工程实例验证结果的准确性,预测的结果表明：考虑岩石破坏机理的网络模拟技术,能充分反映岩体结构面的几何特征,合理地预测地下洞室中的超挖问题。     

高速公路顺向坡层面抗剪强度参数试验研究

对湖北省西部某高速公路宜昌-恩施段主要边坡岩体结构面(层面)的抗剪强度参数进行了较系统的试验研究,包括岩体结构面的野外地质调查、岩体结构面原位直剪试验、软弱结构面室内模拟剪切试验及岩体力学参数估值等.对各种试验数据进行整理、分析和对比,得到了层面抗剪强度参数.在岩体工程分类的基础上,利用Hoek-Brown经验方法对各类岩体强度参数进行了估算.综合以上多种数据,并考虑岩体结构面所处具体地质条件,提出了各类岩体结构面强度参数建议值.     

围岩质量分级的模糊综合评判研究

岩体本身具有许多不确定性和随机性,围岩质量分级取决于许多因素。选择岩石单轴饱和抗压强度Re、岩体完整程度（RQD）、平均节理裂隙间距d、不连续面状态系数f、结构面方位φ以及地下水状态w六个指标,采用模糊数学方法,引入模糊数学隶属函数的概念,建立边坡岩体质量综合评判模型,并将其应用于黄河上游某电站引水隧洞围岩岩体质量评价。评判结果显示,该模型使用模糊综合评价的评价结果与现场定性判断及报告中RMR分类结果基本一致。     

Application of Fuzzy Set Theory to Rock Engineering Classification Systems: An Illustration of the Rock Mass Excavability Index

The characterization of rock masses is one of the integral aspects of rock engineering. Over the years, many classification systems have been developed for characterization and design purposes in mining and civil engineering practices. However, the strength and weak points of such rating-based classifications have always been questionable. Such classification systems assign quantifiable values to predefined classified geotechnical parameters of rock mass. This results in subjective uncertainties, leading to the misuse of such classifications in practical applications. Fuzzy set theory is an effective tool to overcome such uncertainties by using membership functions and an inference system. This study illustrates the potential application of fuzzy set theory in assisting engineers in the rock engineering decision processes for which subjectivity plays an important role. So, the basic principles of fuzzy set theory are described and then it was applied to rock mass excavability (RME) classification to verify the applicability of fuzzy rock engineering classifications. It was concluded that fuzzy set theory has an acceptable reliability to be employed for all rock engineering classification systems.     

A Moisture Index Classification System for Rocks (MiC System)

Summary.  Interaction of rocks with water is leading to a reduction in physical and mechanical properties, and quantifying this effect has always been a problem for design purposes in rock engineering projects. Despite the fact that a number of considerable works have been carried out in this field, they are not thorough and general. In this paper, a new rock classification system is presented in order to evaluate wet rock properties. Laboratory studies showed that six parameters may be recognized as major controlling parameters for wet rocks, including: water absorption, porosity, weathering degree, swelling index, number of microfissures, and average grain size. Many tests were performed and a sensitivity analysis was carried out on the data obtained. This analysis characterized the rock sensitivity when changing each parameter and consequently, a rating value was assigned to each parameter. By adding these rating values, a rating between zero and 100 is allocated to each rock as Moisture index (Mi). The closer this index is to 100, the more sensitive rock will be to moisture. On the basis of this index, rocks are divided into five classes including: very good, good, fair, weak and very weak.     

基于分形理论的岩体工程分类初探

介绍了岩体工程分类的研究现状及发展趋势，指出岩体质量的决定因素是岩体的坚硬程度及完整程度，各种结构面的存在使岩体的坚硬程度及完整程度降低，研究表明，岩体结构面的分布具有很的分形现象，在此基础上，重点论述了岩体工程分类的分形方法。     

模糊聚类分析及在坝基岩体分类中的应用初探

基于模糊聚类的基本理论,提出坝基岩全动态系统综合分类的思路,并针对某建水电站坝基岩体进行试算,初步划分了不同深度岩体的可利用性,为确定合理的建基面提供了一定的依据。     

基于灰色系统理论的改进SMR法初探

综合灰色系统理论与传统的边坡岩体质量分级方法(SMR法),提出改进SMR法。传统的岩体质量分级方法中定量指标取值离散性很大,造成质量分级结果阶梯变化。灰色系统理论的灰度特征对解决这类小样本、离散性的问题有很好的适用性。首先对传统质量分级方法的评价指标进行灰类划分,确定各指标所占权重,再构建评价指标的三角白化权函数,并基于最大隶属度准则对边坡岩体进行质量分级。最后结合工程边坡实例,与一般工程RMR(岩体质量分级)与SMR法比较,改进SMR法的评价结果更加吻合工程现状,且质量分级稳定性高,表明其应用于边坡岩体质量分级是科学和准确的。     

Fuzzy set approaches to classification of rock masses

Rock mass classification is analogous to multi-feature pattern recognition problem. The objective is to assign a rock mass to one of the pre-defined classes using a given set of criteria. This process involves a number of subjective uncertainties stemming from: (a) qualitative (linguistic) criteria; (b) sharp class boundaries; (c) fixed rating (or weight) scales; and (d) variable input reliability. Fuzzy set theory enables a soft approach to account for these uncertainties by allowing the expert to participate in this process in several ways. Hence, this study was designed to investigate the earlier fuzzy rock mass classification attempts and to devise improved methodologies to utilize the theory more accurately and efficiently. As in the earlier studies, the Rock Mass Rating (RMR) system was adopted as a reference conventional classification system because of its simple linear aggregation.

The proposed classification approach is based on the concept of partial fuzzy sets representing the variable importance or recognition power of each criterion in the universal domain of rock mass quality. The method enables one to evaluate rock mass quality using any set of criteria, and it is easy to implement. To reduce uncertainties due to project- and lithology-dependent variations, partial membership functions were formulated considering shallow (<200 m) tunneling in granitic rock masses. This facilitated a detailed expression of the variations in the classification power of each criterion along the corresponding universal domains. The binary relationship tables generated using these functions were processed not to derive a single class but rather to plot criterion contribution trends (stacked area graphs) and belief surface contours, which proved to be very satisfactory in difficult decision situations. Four input scenarios were selected to demonstrate the efficiency of the proposed approach in different situations and with reference to the earlier approaches.     

岩体结构面强度的 Mohr—Coulomb破坏判据与 Barton破坏判据的试验对比

岩体结构面强度是工程岩体稳定性设计中的重要参数,目前工程上常用的两个强度判据,即Mohr-Coulomb准则和Barton准则有各自适用条件。本文在对七组具不同岩性、不同粗糙度及起伏度红层样品进行试验的基础上,探讨了在试验过程中所揭示的强度周期性变化现象,同时基于两准则试验数据,分析了它们之间的区别,获得一些重要结论.即JRC、JCS越大,两准则差别越大;在低法向应力下两准则较接近,在高法向应力时,MC准则偏于危险。     

风化岩体及风化带划分的数学地质方法研究

针对风化岩体仍无理想的定量分带方法这一研究现状与工程建筑需要的矛盾,提出了对能够检测工程环境岩体风化程度的各种物理力学、矿物学和声学指标进行方差分析和特殊的“动态方差分析”方法,可对岩体风化带的划分进行定量评价,达到某一试验结果下的最佳分带效果。还结合应用实例讨论了不同地质条件下分带计算过程的相应变化和应用效果。最后指出,工程岩体分类亦可借鉴本文的研究方法。     

准各向同性裂隙岩体中有效动弹性参数与弹性波速关系的研究

从弹性波在介质中传播的特点和弹性波法在岩体工程中的实际应用情况方面,分析了弹性波在含裂隙岩体介质中的传播特征。将岩体中裂隙呈随机分布的裂隙岩体似为准各向同性裂隙岩体,根据能量平衡原理、岩石断裂力学理论和卡氏最小功能定理(Castiglano’s theorem),确定了准各向同性裂隙岩体的有效动弹性参数( 、 、 )与裂隙密度参数(Xv)的数学关系。在此基础上,根据各向同性介质中传播的弹性波理论,建立了准各向同性裂隙岩体中弹性波速( 、 )和 / 与裂隙密度参数(Xv)之间的关系。理论研究表明,在此裂隙岩体中,有效动弹性参数和弹性波速与裂纹密度参数之间相互的关系均近似成倒数函数的非线性关系;裂隙密度参数增加,有效动弹性模量( )也减少,弹性波速( , )也减小;在裂隙密度参数较小时,此裂隙岩体的有效弹性模量和弹性波速随裂隙密度参数的变化较大,说明裂隙体的有效弹性参数和弹性波速对裂隙体非常敏感。     

岩体稳定性评价的模糊概率方法

岩体稳定性受多种不确定性因素的影响,不仅具有随机性,也具有模糊性,属于模糊概率的范畴,利用经典的模糊综合评判方法进行研究将会导致不合理的结果。在模糊概率理论的基础上,建立了一类新的岩体稳定性综合评价方法——模糊概率方法,并提出了模糊权重的概念,从而避免了权重取值带来的不确定性。结合所选取的5个影响岩体稳定性的因素,建立了这5个影响因素的隶属函数与模糊权重;利用该方法对某一地下岩体工程进行分析,并与其他方法评价的结果进行比较,表明了其方法的合理性与可靠性。     

基于三维裂隙网络的裂隙岩体表征单元体研究

岩体表征单元体（REV）的研究一直是岩土工程中的重要问题。裂隙岩体REV是其内部复杂结构在尺寸效应上的体现,归因于岩体内裂隙系统的随机性。在三维网络模型的基础上通过计算体积节理数建立了确定岩体REV的方法。这种方法考虑了岩体内裂隙的三维空间密度的特征,采用体积节理数这一参数的收敛状况确定岩体REV的大小。建立了实际岩体的模拟裂隙系统,用一定大小的立方体来分割裂隙系统,统计不同立方体内的体积节理数,并将均值作为最终裂隙岩体的参数。将此参数作为裂隙岩体的属性,通过判别其收敛状况获得了岩体REV的尺寸。考虑了岩体不连续面的特征,建立了REV的分析模型,得出工程岩体的REV的尺寸是裂隙平均迹长的4倍的结论。     

Application of the adaptive neuro-fuzzy inference system for prediction of a rock engineering classification system

The rock engineering classification system is based on six parameters defined by Bieniawski [5], who employed parallel sets of linguistic and numerical criteria that were acknowledged to influence the behaviour of rock masses and the stability of rock structures. Consequently, experts frequently relate rock joints and discontinuities as well as ground water conditions in linguistic terms, with rough calculations. Recently, intelligence system approaches such as artificial neural network (ANN) and neuro-fuzzy methods have been used successfully for time series modelling. Using neuro-fuzzy approaches, which enable the information that is stored in trained networks to be expressed in the form of a fuzzy rule base, would help to overcome this issue. This paper presents the results of a study of the application of neuro-fuzzy methods to predict rock mass rating. We note that the proposed weights technique was applied in this process. We show that neuro-fuzzy methods give better predictions than conventional modelling approaches.