Interview with ITA President Z. Eisenstein

Dr. Zdenek (Dan) Eisenstein has been involved in tunnelling for nearly thirty years. He received his undergraduate and doctoral degrees in civil engineering and geo-technical engineering, respectively, from Czech Technical University, Prague. Since 1969, he has been a professor of civil engineering at the University of Alberta in Edmonton, Canada. His research has been oriented toward design and analysis of undeground structures; deep excavations; soil structure interaction problems; and application of numerical methods in geotechnical engineering. He has develop graduate and professional courses in solid mechanics, foundation engineering, tunnelling, light rail transit, and numerical modelling.Prof. Eisenstein has served as a consultant on several hundred projects throughout the world involving dams, foundations, deep excavations, and tunnels. For the Channel Tunnel project, he was engaged to evaluate the compatibility of the tunnel systems with the ground.A member of the Canadian Geotechnical Society and the advisory board of the International Journal for Numerical Methods in Geomechanics, Prof. Eisenstein served as Editor of Canadian Tunnelling from 1985 to 1989. He has lectured extensively on a wide range of topics related to tunnelling, and has published more than 100 papers in journals and conference proceedings.Prof. Eisenstein has served on the Executive Council of the International Tunnelling Association since 1987; he was elected ITA First Vice-President in 1989 and President in 1991. Midway through his presidency, Prof. Eisenstein talked with Tunnelling and Underground Space Technology about the ITA's accomplishments over the past year-and-a half, and his goals for the remainder of his term of office.     

现代土力学研究的新视野——宏微观土力学

随着岩土工程领域的不断拓展,特别是在深地、深海、深空工程（“三深工程”）方面需要面对更多复杂的岩土材料和环境条件。基于连续介质和唯象的常规土力学理论与方法在描述岩土材料的非连续性、大变形和破坏等复杂特性以及复杂环境影响上有许多缺陷。宏微观土力学力图从本质上探求岩土材料复杂宏观特性的微细观机理,建立其多尺度分析理论与方法,解决岩土力学与工程中的疑难与关键问题,从而帮助提高工程设计水平。本文回顾了宏微观土力学近40 a的发展历程,从宏微观土力学的研究方法、理论和应用等方面综述了国内外学者的主要研究成果,包括典型土体的微观特性、微观本构理论、宏微观关联、基于微观机制的宏观本构理论等。研究土体包括陆地上黏土、结构性砂土、黄土、深海能源土和太空土（月壤）。重点阐述了宏微观土力学的重要研究手段之一的离散单元法在模拟陆、海、空疑难岩土力学与工程中的应用与拓展,探讨了宏微观土力学研究所面临的各种挑战和重大机遇。通过系统介绍上述研究成果,勾勒了宏微观土力学的基本框架,以期推动该研究方向的加速发展。     

黄文熙先生的主要学术成就——纪念黄文熙先生诞生100周年

黄文熙先生在结构工程和岩土工程方面都有创新性的研究成果。他提出的拱坝计算的格栅法,是在电子计算机出现以前的结构离散计算方法,也是有限元法计算的先驱;他提出了可以反映土的应力路径的三维地基沉降计算方法;他也是国内外公认的动三轴试验的首创者;他提出了具有突出特色的清华弹塑性模型,大大推动了我国土的本构模型研究的发展。     

UH模型系列研究

岩土材料的本构模型是岩土工程学科的重要理论基础。合理的本构模型既能定性地揭示岩土的变形强度机制,也能定量地进行岩土体强度和变形计算。笔者20余年来潜心于土的本构模型研究,取得了以下3个方面的理论成果:1在修正剑桥模型的基础上,通过引入统一硬化(unified hardening,UH)参数,建立UH模型,该本构模型能够反映饱和超固结土的剪缩、剪胀、硬化、软化和应力路径相关性等特性,模型所用土性参数与修正剑桥模型完全相同;2扩展UH模型,使其考虑多种外部因素(温度、时间和基质吸力)、复杂特性(各向异性、结构性和小应变特性)和复杂加载条件(循环荷载、部分排水即渐近状态)等的影响;3提出广义非线性强度准则和满足热力学定律的变换应力三维化方法,从而实现了本构模型的合理三维化。UH模型已被嵌入到数值计算软件中,并被用于分析岩土工程问题。以上研究包括本构建模、强度准则、三维化方法和数值分析等方面,形成了独具特色的岩土本构理论和应用体系。     

Oriented polymer grid reinforcement

Tensar high strength oriented polymer grids were developed in the UK in the late 1970s. Extensive research has been conducted in Europe and North America to investigate the various civil engineering applications for these materials. The availability of these high strength, durable reinforcing grids has led to many innovative and economical developments in geotechnical and highway engineering. This paper describes the major application areas: reinforced soil walls and slopes, reinstatement of slope failures; embankment foundations over soft soil; reinforcement of road bases for paved roads; and asphalt reinforcement.     

Girdle me with steel

This note presents a brief personal overview of Patrick Dowling’s career and his many contributions to structural engineering. It is broadly chronological in form, and may serve as a key to the some of the more specialised papers in Patrick’s areas of interest that figure elsewhere in this symposium. His enthusiasm for seeing the results of research filter through into engineering practice and design is emphasised.     

岩土塑性力学的新进展——广义塑性力学

多数岩土工程都处于弹塑性状态 ,因而岩土塑性在岩土工程的设计中至关重要。本文首先简要回顾了岩土塑性的发展过程 ,分析了经典塑性力学用于岩土类材料存在的问题 ,指出其采用的 3个不符合岩土材料变形机制的假设。放弃这 3条假设 ,从固体力学原理直接导出广义塑性位势理论 ,从而将经典塑性力学改造成更一般的塑性力学---广义塑性力学。广义塑性力学采用了塑性力学中的分量理论 ,能反映应力路径转折的影响 ,克服了塑性应变增量方向与应力增量无关的错误 ;要求屈服面与塑性势面对应 ,而不要求相等 ,避免了采用正交流动法则引起过大剪胀等不合理现象 ,也不会产生当前非关联流动法则中任意假定塑性势面引起的误差。文中给出了广义塑性力学的屈服面理论、硬化定律和应力-应变关系 ,并在应力增量分解的基础上 ,建立了考虑应力主轴旋转的广义塑性位势理论 ,从而可求出应力主轴旋转产生的塑性变形。通过分析屈服面的物理意义 ,表明屈服条件是状态参数 ,它与应力状态、应力历史及材性等状态量有关 ;同时也是试验参数 ,只能由试验给出。通过实际应用 ,表明广义塑性力学不仅可以作为岩土材料的建模理论 ,而且还可以应用于诸如极限分析等土力学的诸多领域 ,具有广阔的应用前景。     

Application and development of hard rock TBM and its prospect in China

Compared with the drill and blast method, TBM tunnelling has significant advantages with high construction efficiency, low project cost, conducive to environmental protection, favorable stability control of surrounding rock mass, etc. At present in China, it has become the first choice and development trend in the construction of long and deep buried tunnels and over one thousand meters deep coal mine roadways. Recently, the engineering application and fundamental research of TBM tunnelling in China has made great progresses, also unavoidably with some unsolved problems. In this paper, the application and development of TBM manufacturing and tunnelling technologies in China are reviewed and summarized, and the market demand and application prospect are predicted. The complex geological conditions and technical challenges which will be encountered in China’s future TBM engineering are analyzed. Current progresses in the three aspects of TBM fundamental research, technology development, and engineering application are summarized. The development trend of TBM manufacturing and tunnelling technologies in China are prospected.     

建筑声学50年的回顾:贺马大猷教授90大寿

我国的建筑声学在马大猷教授奠定的基础上，20世纪50年代以来，无论在科研、设计、声学材料（结构）的研制和应用方面均有重大发展，在厅堂音质设计的某些领域内还取得了突破性的进展。本文仅就马大猷教授在建筑声学领域内做出的贡献，作简要的介绍。     

Salinity effects on soil shrinkage characteristic curves of fine-grained geomaterials

Fine-grained clayey soils are prone to substantial volume changes during desiccation in response to the dynamics of their moisture regime, and are of critical importance in several geotechnical and geo- environmental engineering applications. As such, the complex interactions between the fraction of soil solids and the ionic pore fluid play a critical role in governing such volume changes, and have been the focus in studies dealing with marine geotechnology, mine-tailing ponds, engineered barrier systems, etc. With this in mind, the present investigation evaluates the volume changes and accompanying densification from a saturated slurry state to a constant volume state of a reference fine-grained geomaterial, kaolin, subjected to evaporative dewatering. For this purpose, several parametric studies involving determination of soil shrinkage characteristic curves (SSCCs) of kaolin under the influence of varied salt constituents and concentrations of pore fluid are performed. Furthermore, a critical assessment of SSCCs depicting progressive shrinkage and volume change behaviour of geomaterials is provided, followed by the analysis of experimentally obtained SSCCs of the kaolin to explore the impacts of pore fluid salinity. Moreover, the SSCCs are parameterised with a predictive model and the fitting parameters are used to quantitatively demonstrate the salinity-dependent volume change response of a representative fine-grained porous system.     

岩土材料强度理论发展现状

在经典连续介质弹塑性理论框架下,结合岩土工程应用背景,总结和论述了岩土材料复杂应力状态下强度理论的发展状况,指出岩土强度理论是水利、土木、矿业、铁道等工程中结构件设计和强度计算必要的基础理论,因此强度理论得到广泛的研究和应用。     

有效应力决定饱和岩土材料抗剪强度的摩擦学解释

有效应力决定了岩土材料的变形和强度，有效应力概念虽然已在岩土工程中广泛应用，但是，对于决定饱和岩土材料抗剪强度的有效应力，其理论解释至今却并不充分且受到质疑。为此，通过文献分析，确定了宏观抗剪强度与粒间摩擦强度之间的正相关关系，并运用摩擦学中的黏着摩擦理论，推导了排水和不排水条件下，粒间接触面黏着结点的生长公式和抗剪强度公式。通过对比分析这两种条件下的应力状态对抗剪强度的作用影响，得到了与 Terzaghi 一致的有效应力表达式，并在此基础上，探讨了有效应力和有效应力原理的基本概念和定义。     

新工科背景下土力学案例教学研究

新工科背景下土木工程专业对学生的应用能力培养要求越来越高,但是课堂教学与实践又是一对现实存在的矛盾体。近年来,注册岩土工程师考试试题越来越贴近工程实际,适宜用来进行课堂案例教学。我国注册岩土工程师考试分两阶段:第一阶段是基础考试,主要考查考生是否基本掌握必备的专业理论基础;第二阶段是专业考试,考查考生按照国家法律、法规及技术规范进行岩土工程的勘察、设计、施工及解决实践问题的能力。通过对历年注册岩土工程师基础考试和案例考试中土力学相关问题的研究,对注册工程师考试试题做适当改变后引入土力学课堂教学,可以增进学生对知识的理解,更形象地了解知识在工程实践中的应用,加强应用能力的培养,同时为学生毕业后参加注册工程师考试奠定良好的理论和实践基础。     

计算机和信息管理技术在岩土工程中的应用现状与前景

一直以来,研究解决岩土工程相关问题的主要基本理论为岩土力学。然而,现代岩土工程涉及的范围愈来愈广,深入地下空间愈来愈深,遇到的问题愈来愈复杂,对计算结果的可靠性和实用性要求愈来愈高,因此,在发展完善传统基本理论的同时,引进了大量的先进技术、研究方法和手段,而且卓有成效。本文重点论述了在岩土工程研究领域,计算机信息管理技术的应用现状、发展趋势和广阔前景。     

Rock mechanics for design of Brisbane tunnels and implications of recent thinking in relation to rock mass strength

This paper explores the potential implications of recent thinking in relation to rock mass strength for future tunnelling projects in Brisbane, Australia, particularly as they are constructed within deep horizons where the in situ stress magnitudes is larger. Rock mass failure mechanisms for the current tunnels in Brisbane are generally discontinuity controlled and the potential for stress-induced failure is relatively rare. For the road tunnels which have been constructed in Brisbane over the last 12 years, the strength of the more massive rock masses for continuum analysis has been estimated by the application of the Hoek-Brown (H-B) failure criterion using the geological strength index (GSI) to determine the H-B parameters m_b, s and a. Over the last few years, alternative approaches to estimating rock mass strength for ‘massive to moderately jointed hard rock masses’ have been proposed by others, which are built on the work completed by E. Hoek and E.T. Brown in this area over their joint careers. This paper explores one of these alternative approaches to estimating rock mass strength for one of the geological units (the Brisbane Tuff), which is often encountered in tunnelling projects in Brisbane. The potential implications of these strength forecasts for future tunnelling projects are discussed along with the additional work which will need to be undertaken to confirm the applicability of such alternative strength criteria for this rock mass.     

土工试验成果在岩土工程勘察中的应用

阐述了土工试验对于岩土工程的重要性,对土工试验成果表的组成及各组成部分在成果表中的作用进行了详细介绍,并结合实例论述了土工试验成果在岩土工程勘察中的具体应用,以指导今后工程实践。     

Neural Networks in Civil Engineering: 1989–2000

The first journal article on neural network application in civil/structural engineering was published by in this journal in 1989. This article reviews neural network articles published in archival research journals since then. The emphasis of the review is on the two fields of structural engineering and construction engineering and management. Neural networks articles published in other civil engineering areas are also reviewed, including environmental and water resources engineering, traffic engineering, highway engineering, and geotechnical engineering. The great majority of civil engineering applications of neural networks are based on the simple backpropagation algorithm. Applications of other recent, more powerful and efficient neural networks models are also reviewed. Recent works on integration of neural networks with other computing paradigms such as genetic algorithm, fuzzy logic, and wavelet to enhance the performance of neural network models are presented.     

水平矩形浅锚极限抗拔力分析

在对锚板极限抗拔力进行分析时,既有研究手段和方法基本上都建立在相关联流动法则和岩土体材料的线性破坏准则基础上,然而大量实验成果证实岩土体材料一般并不遵循相关联流动法则且破坏准则具有非线性,因而现有极限抗拔力计算结果往往偏大。在上限定理的基础上,根据非相关联流动法则和非线性破坏准则,分别通过修正岩土材料的抗剪强度参数c*,φ*引入非关联流动法则和通过"切线法"引进非线性抗剪强度指标ct,φt的方法,研究了水平矩形浅埋的极限抗拔承载力问题。研究结果表明:岩土体材料的剪胀特性和岩土材料破坏准则的非线性对锚板基础的承载能力和稳定性有着重要的影响,因而客观评价岩土体材料的真实力学特性将更加符合工程实际。     

Assessment of ground conditions with respect to mechanised tunnelling for the construction of the extension of the Athens Metro to the city of Piraeus

This paper refers to the proposed western extension of the Athens Metro to Piraeus city. The railway consists of a 9.45 m diameter, 8.2 km long tunnel and seven stations. Tunnelling works are expected to be undertaken within a variety of lithological formations ranging from very strong alpine limestones to recent soft littoral deposits. The tunnel alignment was divided into 12 areas with respect to the geological and geotechnical conditions that may be encountered during construction. In many of these zones, the geotechnical conditions together with the presence of sensitive surface and/or subsurface structures led to the selection of a closed-face TBM (Earth Pressure Balance Machine or Slurry Tunnel Boring Machine) as the appropriate tunnelling technique. The Piraeus extension is a project where in places both types of commonly used closed-face tunnelling machines will encounter ‘text book’ application areas, but not always. The applicability of each type of TBM is discussed using the available data obtained from an extensive site investigation.      

Unified description of different soils based on the superloading and subloading concepts

Geotechnical engineering often involves different types of geomaterials, such as sandy soil and clayey soil. Existing studies have confirmed that these soils have some common features, i.e. their mechanical behaviors depend not only on the inherent characteristics but also on their initial states. To describe the main mechanical behaviors of different soils within a simple and reasonable constitutive framework is of great significance for the numerical analysis on geotechnical engineering. This paper first introduces a model based on the concepts of superloading and subloading, which considers the “state dependence” (effects of overconsolidation and structure) of soil and only adds two material parameters compared with the Cam-Clay model. Secondly, conventional triaxial tests are systematically carried out on four types of soils (i.e. sand, silty clay, clay, and intermediate soil) with different initial void ratios, and the mechanical similarities and differences of these soils are discussed uniformly. After that, six material parameters of these soils are uniformly determined based on the concepts of superloading and subloading, and then used in constitutive calculations to verify the feasibility. The calculated results show a good agreement with test data, indicating that the model based on the concepts of superloading and subloading has great potential for describing the general mechanical behaviors of different soils within a unified framework. This work is expected to be applied to constitutive selection and parameter determination in the geotechnical numerical analysis of complex soil profiles.