L'essai de torsion et la résistance au cisaillement des roches

Rock Mechanics and Rock Engineering - Cette étude présente un appareillage de torsion mis au point au laboratoire de Mécanique des Roches d'Electricité de France. Les...     

Ein Beitrag zur Mechanik des Gebirges um einen tiefliegenden Hohlraum im Post-Failure-Bereich

ZusammenfassungEin Beitrag zur Mechanik des Gebirges um einen tiefliegenden Hohlraum im Post-Failure-Bereich Ausgehend von Brucherscheinungen beim Vortrieb verschiedener österreichischer Tunnel wird eine von bisherigen Auffassungen abweichende Vorstellung über den Bruchmechanismus ausbruchnaher Bereiche tiefliegender Gebirgshohlraumbauten zur Diskussion gestellt. Versuche an exzentrisch gedrückten Prismen, deren Beanspruchung jener des Gebirges um einen Hohlraum ähnlich ist, führen in weiterer Folge zur Behandlung des vorliegenden Problems nach den Regeln der Bruchmechanik.

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SummaryA Contribution to the Mechanics of Rock Surrounding a Deep-Seated Excavation in the Post-Failure State Based on fracture phenomena observed during the advance of various Austrian tunnels a new conception of the fracture mechanism of the regions surrounding deep-seated cavities is presented for discussion. Experiments carried out on eccentrically loaded prisms, the stress of which is similar to the one resulting from excavating have shown that a further investigation of this problem on the principles of fracture mechanics will be necessary.

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RésuméUn article traitant la mécanique des roches enceindrant une excavation profonde dans la phase Post-Failure Partant des phénomènes de cassures lors des travaux d'avancement de divers tunnels autrichiens, nous mettons en question une conception divergente des idées jusqu'alors usuelles du mécanisme des cassures, concernant les excavations des massifs rocheux situées en grande profondeur. Une charge excentrique comparable à la sollicitation des roches autour d'une cavité artificielle fut appliquée à des échantillons prismatiques. Ces expériences nous ammènent par conséquent à traiter ce problème (ci présent) d'après les règles de la mécanique des cassures.

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Vorbericht über eine Dissertation am Institut für Geologie der Technischen Universität Wien.

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Mit 14 Abbildungen     

青藏高原羌塘-三江地区残留微陆块

综合研究历年区调成果,发现西藏羌塘-三江地区残留若干微陆块,有相同或相似的岩石组合,主要变质期(1800Ma)变质相、构造变形性相近。原是一个有成生联系的微陆块群,有层无序、顶底不全,多系构造接触的中高级变质岩系。历年建立的羌塘戈木日岩群,三江地区宁多岩群、雄松岩群、石鼓岩群、苍山岩群、哀牢山岩群、吉塘岩群、崇山岩群、大勐龙岩群等12个岩群,依据区域对比、上覆地层及同位素年龄,统归古元古界(Pt1),构成本区早期大陆地壳-结晶基底。羌塘 三江残留微陆块群南接越南"印支地块",北邻西域陆块,东邻扬子陆块,南邻冈底斯 察隅陆块,是介于欧亚板块与印度板块之间的接合部位,具有独立地质构造演化及成矿特征的构造域,建议称为"羌塘-三江古-中特提斯构造域"。     

Book review

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Assessment of texture coefficient for different rock types and correlation with uniaxial compressive strength and rock weathering

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Book reviews — Buchbesprechungen — Critique de livres

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The lithostratigraphy of the English Chalk Rock

The Upper Turonian Chalk Rock occurs within a nodular unit within the otherwise generally soft, white chalk that dominates the English Upper Cretaceous. The nodular unit is condensed, and contains a number of hardgrounds that are designated here as the Chalk Rock Formation. The Chalk Rock contains some seven or eight hardgrounds, most of which are lithologically distinctive and can be traced over distances of up to 250 km. Nine beds within the Chalk Rock are named, comprising six hardgrounds and three marl seams. The lowermost widespread hardground appears to be more or less equivalent to the “Spurious Chalk Rock” of the south coast of England. In two areas the thickness of the Chalk Rock is greatly diminished. The most marked area, in west Wiltshire, is located close to the Palaeozoic Mendip Hills and indicates that the Mendip structure has influenced Turonian sedimentation. The other region of thinning is a platform-like area in the eastern Chiltern Hills WNW of London.     

Comment on the paper by S. Kielbassa and H., Duddeck: Stress — Strain fields at the tunnelling face — Three-dimensional analysis for two-dimensional technical approach

Rock Mech. Rock Engng. 24 (3), 115–132, 1991.     

Qualitative Analysis of Rock Avalanches Propagation by Means of Physical Modelling of Non-Constrained Gravel Flows

Summary This paper presents an experimental study of rock avalanches run-out and propagation carried out with a small-scale physical model at the EPFL Rock Mechanics Laboratory. Fall height, volume, releasing geometry and materials used for testing have been varied and their influence on deposit characteristics (such as length, width, height and morphology) and run-out has been studied. The experiments have shown that deposit morphology is dependent on the type of material used: sand or gravel. Sand deposit shape, regular and compact, is in accordance with many tests described in the literature, while Aquarium gravel deposit is closer to real cases such as the Six des Eaux Froides event (Switzerland). There is also a considerable difference in deposit morphology and dimensions when the event is the consequence of one large volume released at once or when the same volume is released at different times. In this latter case the final deposit characteristics do not depend on the entire failed volume but on the individual smaller ones. This behaviour is in agreement with the Randa event (Swiss Alps) which occurred over several hours. For all-in-once releases, run-out distance depends primarily on the volume. Fall height and releasing geometry have a small influence on run-out, but on the other hand a higher fall height leads to a different lateral spreading and to the development of two different propagation mechanisms of the sliding mass. Author’s address: Irene Manzella, Rock Mechanics Laboratory, Swiss Federal Institute of Technology, Lausanne, Switzerland     

南祁连东段化隆岩群形成时代的进一步限定

作为南祁连造山带基底残块的化隆岩群,由于产出有与Cu-Ni(-PGE)矿紧密相关的基性-超基性岩而倍受关注。随着一些新元古代精细锆石同位素年代学数据的获得,化隆岩群形成于太古-古元古代的传统认识发生了动摇。通过高精度的LA-ICP-MS(激光剥蚀等离子体质谱)锆石微区原位U-Pb同位素测年,获得青海省湟源县南日月乡一带化隆岩群条带状二云斜长片麻岩(副变质岩)最新的蚀源区年龄为891±7Ma,代表化隆岩群形成时代的下限;条带状黑云斜长角闪岩(原岩为中性火山岩)的形成年龄为884±9Ma,将化隆岩群的形成时代进一步限定为新元古代。认为化隆岩群火山-沉积作用应为Rodinia超大陆裂解的地质记录,Rodinia超大陆裂解事件及其相关的成矿作用在祁连造山带及其邻区前寒武纪占据不可低估的重要地位。     

Technique and apparatus for strain measurements on rock in constant confining pressure experiments

Rock Mechanics and Rock Engineering - An indirect scheme to measure radial strains on competent rock cylinders and joint deformations in jointed specimens subjected to conventional triaxial...     

江苏埤城岩群岩石物理性质

对ZK03孔岩芯物性测定,获得了埤城岩群密度、磁化率、剩余磁化强度和电阻率、极化率5项物性参数。埤城岩群有较高的密度,与围岩的密度差达0.15×10³ kg/m³,具有重力勘探的物性前提;埤城岩群有较高的电阻率,与部分围岩电阻率差异明显,可有条件的开展电阻率勘查工作;埤城岩群具低磁性和低电化学活动性,磁测和激电方法应慎用。     

我国岩石力学学科结构及其演变初探

以中国岩石力学与工程领域公认最有影响力的中文核心期刊《岩石力学与工程学报》创刊25年来的论文为研究对象,基于科技史理念、以中图分类法为依据,对我国岩石力学的学科结构及其演变开展研究,从一个侧面对中国岩石力学学科发展轨迹进行梳理和勾勒,对学科的发展历程进行探究。     

A portable shear box for testing rock joints

Rock Mechanics and Rock Engineering - The authors describe their early work on the development and operation of a portable shear box for testing rock joints. Experiences with sampling, roughness...     

青藏高原冈底斯北缘卡穷岩群形成时代的确定

冈底斯北缘的卡穷岩群为一套中高级变质岩系,其形成时代至今未得到有效限定。通过高精度的LA-ICP-MS(激光剥蚀等离子体质谱)锆石微区原位U-Pb同位素测年,获得西藏八宿县同卡乡北卡穷岩群条带状斜长角闪岩(正变质岩)上交点年龄为(1082±18)Ma,将该岩群原岩形成时代厘定为中元古代末,即晚蓟县世。同时,获得卡穷岩群中片麻状二长花岗岩的上交点年龄为(549±18)Ma,属于泛非期构造-热事件的岩浆作用记录;结合野外地质和岩相学特征,认为该岩体为卡穷岩群变质火山-沉积岩系部分熔融的产物,岩浆未发生远距离运移侵位。泛非运动之后,卡穷岩群还经历一次(416±23)Ma强烈的构造作用,这次构造作用的地质意义值得进一步研究。     

黑龙江林口西北楞石墨矿地质特征及成矿规律

黑龙江林口西北楞石墨矿位于佳木斯—兴凯(地块)Fe-Au-P-石墨-矽线石成矿带（Ⅲ-53）中部,为一沉积变质超大型晶质石墨矿床。赋矿层位为上元古界兴东岩群大盘道岩组下段(Pt3dp1.),构造较为简单,矿带延展长度约为9.5 km,共圈定石墨矿带6条、石墨矿体73条。矿床地质特征及地球物理特征明显,极具代表性,总结研究其地质特征及成矿规律,对黑龙江东部佳木斯隆起兴东岩群大盘道岩组的区域矿产勘查工作具有一定的参考价值。     

昌化鸡血石常见地子的成分与岩性

从临安昌化镇和大峡谷镇采集了一百多个昌化鸡血石样品,分别对其作了岩石薄片鉴定、红外分析、X射线衍射分析,归纳总结了常见鸡血石种类的成分和岩性:冻地主要成分为地开石/高岭石,岩性为粘土质岩石;软地主要成分为强粘土化火山碎屑或粘土,岩性多为强粘土化凝灰岩-粘土质岩石;软刚地主要成分为蚀变火山碎屑/明矾石,岩性多为明矾石岩或中等粘土化/明矾石化凝灰岩;硬刚地主要成分为石英,岩性为弱明矾石化/弱粘土化凝灰岩;硬地主要成分为石英,岩性为弱-强硅化凝灰岩。     

The Cherty Rock,Elgin: A petrographic and isotopic study of a Permo-Triassic calcrete

The Cherty Rock is a laterally persistent horizon that extends across the Inner Moray Firth Basin, northeastern Scotland. The southern exposures of the Cherty Rock near Elgin reveal an indurated carbonate and silica-rich horizon (0·75-10m thick) developed in the uppermost part of the largely aeolian Lossiemouth Sandstone Formation. Laminated, pisolitic, and brecciated textures within the Cherty Rock confirm that the horizon represents an analogue to Recent calcretes of semiarid areas. Textures characteristic of silcretes are widespread in the Cherty Rock but these originate from silica replacement of calcite. The carbon and oxygen stable isotopic composition of micrite in the Cherty Rock (mean σ ¹³C = -6·9%°, mean σ ¹⁸O = -5·7%°, both relative to PDB) is comparable to that of other Permo-Triassic calcretes and modern soil carbonate, suggesting that similar processes were responsible for their formation. The σ ¹³C and σ ¹⁸O values for calcite in the Cherty Rock may indicate that evaporative processes contributed to its development. σ ¹⁸O data from spar (mean σ ¹⁸O = -9·8%° PDB) and macroquartz (mean σ ¹⁸O = 19·7% SMOW) indicate that these are later (burial) cements. The Cherty Rock is a useful stratigraphical and palaeoclimatic indicator, and its presence in the Inner Moray Firth basin suggests a period of tectonic stability in the basin during late Triassic times.     

郯庐断裂带南段并无巨大平移—来自安徽境内的证据

本文根据新近1：5万地质填图和构造调查所获资料，依据郯庐断裂带两侧标志地质体（西冷岩组火山岩，宿松岩群和肥东岩群中磷矿层，大别岩群和阚集岩群）的构造型式和错位情况，拉伸线理的性质和动向，以及郯庐断裂带两侧的次级断裂带特征等，都不能判定郯庐断裂带存在巨大左行平移，故认为大别－苏鲁造山带呈弧形展布，基本代表了原始构造方位，郯庐断裂带是多期构造变动形成的负向构造带，综合造就的一种假位错效应。