葛洲坝工程基岩稳定性的试验研究

本文综述了我所71～78年来为葛洲坝水利枢纽第一期工程进行的基岩稳定性研究工作,其中包括,地应力对基坑岩体稳定性的影响,粘土岩软弱夹层,特别是泥化夹层的长期稳定性和长期强度。通过地应力实测,证实了即使在褶皱轻微、地形平缓的红色岩层中仍可能有较大的构造应力存在,它的局部释放会直接影响岩体稳定。并且有力地说明了构造运动作用是粘土岩泥化的主要原因之一。根据对粘土岩的物理化学和力学性质以及物质结构特性的研究,指出了在外力作用下,当其亚微观结构或微观结构受到破坏时,因粘土颗粒大量吸水膨胀而可能产生泥化。根据现场和室内的剪切蠕变和室内的剪切松弛以及扭转蠕变试验结果,指出了粘土质粉砂岩、砂岩、粘土岩软弱夹层均具有显著的流变特性,提出了确定长期强度的方法。     

Fabric Analysis of Surrounding Rock of Erjiang River Foundation Pit at Gezhouba Dam

The foundation pit of Gezhouba Dam at the part of Erjiang River was discovered to remove in surrounding rock during excavation. For the purpose of ingestigation of its causes, a fabric analysis method is adopted in this paper. The occurrence of each fabric factor can be accurately measured and calculated by the mathematical statistics, so as to analyse the formation conditions of rock and the genesis and development of various tectonic movements. The orientation and magnitude of rock stresses are studied due to changes of crystal lattice of rock-forming minerals caused by differential movements inside the rock. Twelve pieces of sample which were cut off from the original rock as the Dam site were fabrically analysed respectively by X-ray method and microscope (F fabric) method. By comparing with each other, the orientation and magnitude of the tectonic stresses were obtained. It is shown that the orientation and magnitudes of in-situ geo-stress as determined from the fabric analysis are in accord with the results obtained from engineering geology or in-situ stress measurement. From this research, the orientations and magnitudes of geo-stress determined by the fabric analysis are found to be ;suitable for evaluating stability in rock engineering.     

葛洲坝二江基坑围岩岩组分析

葛洲坝二江基坑在开挖期间发现围岩移动,为了研究其原因,本文采用了岩组分析的方法.该法能精确地测量各组构要素的产状和利用数理统计来计算,从而分析岩石的形成条件和各种构造运动的成因与发展.通过岩组分析研究岩体内部产生差异运动引起造岩矿物的品格变化而形成的应力方位及其强弱。为此在二江基坑围岩沿一剖面取样12片,分别进行了 X 射线岩组和显微镜-费氏台岩组分析,将其结果进行对比,得出地质构造应力方位及其强弱.实践证明岩组分析得出的地应力方位及强弱与工程地质、地应力测量等方法所得的结果是一致的.通过这次试验研究证明利用岩组分析所得的地应力方位及其强弱对岩体工程稳定性评价是有意义的.     

旋挖钻机在某电厂桩基工程硬岩地层中的应用

在内蒙古某电厂桩基工程施工中，采用旋挖钻机，配以底部镶嵌截齿的筒式钻头及双头螺旋钻头，顺利地完成了2000根桩的硬岩地层的施工任务。     

Relation Between the Geologic Structure Feature and Rock Strength Performance of Red Rocks in Gezhouba

In this paper, the relation is studied between the geologic structnre feature and rock strength by means of the theories and methods of rock mechanics with geomechanics combined. According to geologic structure feature of red rocks in Gezhouba has been obtained the strength performance and constitute mechanism. In this paper, a concept and method which would play an important part in rock engineering and theories of rock mechanics are proposed.     

葛洲坝红色岩体地质构造特征与岩体强度特性

本文利用岩体力学与地质力学相结合的理论和方法,对葛洲坝红色岩体的地质构造特征与岩体力学特性之间的关系进行了研究,获得了该岩体强度特性及其形成机理。提出了地质构造形迹是构成工程岩体力学问题和形成岩体特性的一个重要因素。本文所采取的研究途径和研究结果,对于岩体工程实践和岩体力学理论研究具有重要意义。     

The Use of Acoustical Log for Exploration of the Rock Foundation

This paper describes how the acoustical log technique is applied to the exploration work on rock foundation . In order to analyze the results obtained from the acoustical measurement by single hole and cross-hole transmission techniques, two modelling tests were carried out. By the use of acoustical refraction and transmission technique, the authors have been conducted a lot of field tests since 1973 in several engineering works to determine the size of underground cavities.     

声波测井在岩石地基探测中的应用

本文介绍我所声波测井技术在岩质地基勘测中的应用情况.作者自1973年以来在这方面进行了大量的野外工作,为了进一步阐明单孔测井及孔间透射波测井中所遇到的岩体声学问题,先后进行了两次室内模型模拟试验研究.在此基础上,用声学的原理和方法阐述了折射波测井及采用孔间透射波法测量溶洞大小的方法.并介绍这些方法在工程实践中的应用.     

Performance of a Pier Group Foundation in Swelling Rock

Foundations on claystone with swell potential may experience upward movement and failure. In this case study, the cause of 58 mm upward movement of drilled-in piers is analyzed using survey data, extensometer readings, and moisture content monitoring of claystone at the site. Laboratory swell tests were conducted to characterize the swelling characteristics of the weathered rock. A swell potential analysis for the pier group foundations is presented. The interaction of the pier group with the swelling rock is considered in analyzing the initiation of the upward movement. Furthermore, a novel inverse analysis method is presented to integrate the laboratory swell test results and numerical modeling to identify the representative swell pressures acting on the pier group as well as upward movement of the pier system. The numerical analysis indicates that the studied pier system is expected to have 135 mm heave and its rate of upward movement is compared with field observations. The behavior of the pier group foundation in swelling rock under various pier spacings and superstructure pressures shows that the uplift is considerably less for piers with smaller center-to-center spacing. The results of pier group numerical modeling provide the correlation of upward deformation changes due to center-to-center spacing of the piers, pier diameters and superstructure pressures.     

Rock cut stability assessment in mountainous regions

Ensuring stability of rock slopes is an essential requirement in the progress of our societies today. Rock determined to be loose or with potential for failure must be removed or restrained in some way. In our work, after doing an inventory of the instabilities that occurred in the last 5 years in the Basque Country, we analyse the different factors, in slope stability. The potential for failure is evaluated for different classes of rock mass, characterized previously by their geomechanical properties. The characterization of potential risk of each one is undertaken by considering 10 parameters that define the nature of mass rock, relative orientation and morphological features of the slope (interaction rock massif-slope) and infrastructure features (interaction rock massif-slope-infrastructure). Each of these parameters is evaluated separately and a Risk Factor (RF) is determined. The RF reaches a maximum value of 10,000 and allows to differentiate four categories of slopes; each category has its own priority. Rock mass characteristics also determine the potential damage from instability and the associated correction measures. The systematic evaluation of instabilities must allow establishing a priority in the correction measures and thus optimise the available economic resources.     

三灰桩地基处理方法在工程中的应用

在二灰桩的桩体材料中加入适量水泥,形成三灰桩。加入的水泥,通过桩体材料之间,以及这些材料与桩周土发生的一系列物理化学反应,不仅提高了桩体的强度,而且改变了桩间土的力学性质,在桩身周围形成硬土壳,共同形成较高强度的复合地基。经静力触探法检测,三灰桩锥尖阻力平均达11.45MPa(6根桩),而二灰桩平均只有4.8MPa;单桩复合地基载荷试验表明,三灰桩与二灰桩相比,P-S曲线无明显拐点,当S=0.015B时,三灰桩P值为240kPa,二灰桩P值180kPa。故三灰桩可大幅度地提高复合地基承载力。     

The Diavik Waste Rock Project: Implications of wind-induced gas transport

Wind-induced gas transport in a test-scale unsaturated waste rock pile was investigated at the Diavik diamond mine, Northwest Territories, Canada. Differential gas pressures were measured in 2008 at 49 locations within a field-scale experimental waste rock pile (test pile) and at 14 locations on the surface of the test pile at 1-min intervals. Wind speed and direction were measured at 10-min intervals and decomposed into north, south, east, and west vectors. Correlations between wind vectors and pressure measurements indicate that the wind influences pressure fluctuations in the test pile. The strength of the correlation is roughly inversely proportional to the distance between the measurement ports and the atmospheric boundary. The relationship between the magnitude of the wind vector and pressure fluctuations on the surface of the test pile is non-linear. However, the relationship between internal and surface pressure measurements is linear, suggesting that gas flow within the test pile follows Darcy’s Law. Spectral analysis demonstrates that the dominant periods of the wind range from 1 to 14 d. A 1-D analytical solution to the flow equation is used to demonstrate that long periods have the most pronounced effect on transient gas flow within the test pile and that the penetration depth of the wind-induced gas pressure wave is a function of wind period and permeability of the test pile.     

Interaction of a Masonry Dam and the Rock Foundation

The Urft dam is an old German gravity dam located in the Eifel near Cologne. In order to ensure its stability and for adjustment to today??s technical standards rehabilitation works were required. Two inspection galleries were excavated below the storage level by means of smooth blasting. To reduce the porewater pressure acting on the dam??s base and thus to increase the stability of the dam also the drainage system was reconstructed and improved. Because the Urft dam is curved, its load bearing behavior reveals a certain arching effect. In order to take advantage of this arch action the stability proof was carried out by means of three-dimensional analyses according to the FEM. In these analyses the interaction of dam and the foundation rock was accounted for. Explorations, laboratory and in situ testing of the masonry and the foundation rock were carried out and a monitoring program was established. The monitoring results allowed a calibration of the three-dimensional model for stability analyses by means of back analyses. On this basis the final stability proof could be conducted.     

信息化施工管理在软土深基坑工程中的应用

介绍了在软土深基坑工程施工中根据现场试验及变形监测反馈的信息，进行了动态设计和信息化施工，采取了一系列的加固措施和施工调整，使整个工程达到了安全可靠和经济技术合理的目的。     

基础桩孔施工中旋挖钻具的选择

根据基础桩孔施工生产的实际情况，对镶齿锥型螺旋钻头、套齿短螺旋钻头、无前导式冻土短螺旋钻头、前导式平底长螺旋钻头、硬地层捞砂钻斗、无隔板式硬岩工程钻头、底开式钻斗、双底捞砂钻斗从结构特征、适应地层到使用注意事项进行对比探讨，并分别简要进行了实例分析。     

三峡工程动工以来葛洲坝水库河床演变分析

根据葛洲坝水库固定断面资料,分析了三峡工程动工前葛洲坝水库河道演变情况和水库冲淤特性,重点分析了三峡工程动工以来葛洲坝水库河床演变情况.认为,三峡工程动工以来葛洲坝水库冲淤特性保持不变;三峡工程施工对河道的影响主要集中在两坝之间一是大量的弃渣加大了某些年份两坝间河道的泥沙淤积,二是粗化了床沙的组成,其中以一期工程施工期影响最大,大江截流以后情况好转.三峡工程动工以来,水库累计冲刷量为3 616×104m3,主要集中在常年回水区河段,其中两坝间累计冲刷量为2 321.1×104m3.1998年特大洪水是水库冲刷的主要原因.     

注浆技术在洛湛铁路岩溶路基施工中的应用

洛湛铁路D1K41+300~84585段路基上部土层松散，下部岩体(石灰岩)溶洞发育，根据工程地质水文地质情况，确定注浆参数和注浆方式，在土体和岩体中通过不同的浆液注浆，固结、充填松散的土层和岩体中的溶蚀、溶洞、溶槽等，使之形成完整的固结体，从而加强岩溶路基的承载力，确保铁路正常运营。介绍了注浆施工工艺及注浆效果。     

潜孔锤旋挖钻机组合在基岩桩施工中的应用

空气潜孔锤钻进工艺和旋挖钻机钻进工艺相结合，充分发挥了潜孔锤对硬、脆、碎基岩地层施工小口径速度快的优越性，也发挥了旋挖钻机施工大口径速度快的优越性，同时也拓宽了旋挖钻机对中～硬基岩施工的领域，提高了旋挖钻机施工中～硬基岩桩基的效率，为旋挖钻机施工类似中～硬基岩提供了技术参考和经验借鉴。     

膨胀岩的时效性在深基坑支护工程的应用

鉴于膨胀岩物理力学特性及其工程特性的研究,结合深基坑支护工程使用时间短的自身特点,寻找膨胀岩抗剪强度衰变期与基坑支护工程使用安全期之间的关系,提出如何利用这种时差效应,为工程带来更多经济效益的设计取值方法。以南宁市昌泰东盟园深基坑支护工程为例,通过不同时期的勘察取样以及采取的不同试验方法分析,进一步佐证膨胀岩时效性在深基坑支护工程设计施工中的应用价值。     

咬合桩技术在深基坑工程中的应用

通过工程实例,介绍钻孔咬合桩在深基坑支护工程中的应用情况以及咬合桩施工技术要点;利用延缓混凝土凝固时间的方法,巧妙地实现了相邻桩间的切割咬合。