金刚石钻井岩石可钻性研究新方法

在比较了现有岩石名钻性研究方法的基础上，选择实验室微钻法来研究金刚石钻井岩石可钻性，并选用综合参数（ｈ／Ｐ）／ｑ作为岩石名钻性指标，通过室内微钻试验，表明该参数确定岩石可钻性更为合理。     

SDY-1型微钻试验机

微钻机是一种用小尺寸钻头进行模拟钻进的钻机，是进行岩石破碎和可钻性研究的必要手段。1984年地矿部频布的《金刚石岩心钻探岩石可钻性分级表》（试行）中将微钻指标列为岩石可钻性分级的指标之一，因此微钻机就成为岩石可钻性分级的主要设备之一。由于微钻要求稳定的钻压和转速，且要求将较短时间内的钻进参数和钻进指标准确无误地记录下来，因此微钻机必须能稳定加压并正确测试各钻进参数和钻进指标。我们在完成岩石可钻性分级研究课题的过程中，研制了较为适用的SDY-1型微钻机，用其钻进了400余块岩样。现将该微钻机简要介绍如下。     

用钻进参数仪实时判层

利用钻进参数仪采集的各岩石的钻速、钻压、转速3个参数数据进行回归分析,计算各种岩石的视可钻性指数,并在钻进中实时判层。      

金刚石钻进的岩石可钻性及其钻速预估

讨论了金刚石钻进的岩石可钻性。认为钻速并不是可钻性,而是可钻性的表观反映。划分岩石可钻性不能用钻速作标准。影响钻速的因素包括反映生产技术水平的可控因素和反映岩石属性的不可控因素。不可控因素的量值指标——可钻值,可表示为压入硬度的指数函数。它反映了金刚石回转钻进时岩石抵抗破碎的能力,可用以划分可钻性级别的指标。根据水平系数和可钻值,可预估钻速。     

金刚石钻进微钻法岩石可钻性分级的探讨

岩石可钻性的分级是确定生产定额、设计钻头和选择最佳参数的依据。本文论述了作者在实验台上用微钻法进行岩石分级的研究成果。该实验台是自行设计并可以同时自动记录9个钻进参数的一种装置,微钻法可以很好地表示在两向力同时作用下,岩石破碎过程的主要力学特征。岩石抗破碎阻力是岩石机械性质的综合反映,因此,以往用单一的性质来进行分级并不完善,用微钻法进行分级、经野外实践,符合率可达85％以上。     

基于岩石可钻性分级的月壤可钻性初探

在分析"Apollo"和"Luna"月表实钻进取心对象的基础上,依据相关的概率分析结果,得出在月表钻进遇见岩石的几率≤5%,月表钻进对象是月壤的可能性为95%;分析了月壤的物理力学特性,确定月壤的内摩擦角和内聚力是影响月壤可钻性的主要特性参数,基于岩石可钻性模型建立了以内摩擦角和内聚力为主要参数的月壤可钻性的初步模型;对"Luna"与"Apollo"的月表钻探取心在钻进方法、钻头材料、钻进深度和钻进速度等方面进行了分析比较,参考岩石可钻性分级指标,得到了月壤可钻性的初步评价结果。     

K-20微钻实验台

利用微钻法测定岩石可钻性等级与实际生产中所反映的岩石可钻性对比性强，是作为部颁标准中测定岩石可钻性等级的主要方法之一。K-20微钻是为野外生产队、省级研究室和钻头制造厂设计的。该实验台采用液压给进，结构轻便、易于操作、造价低，经过野外队、省局研究室和金刚石钻头制造厂的二年多来的使用，认为是解决钻探生产定额有争议的有效设备，如果与万分之一天平配用还可进行岩石相对研磨性指标的测定。也可作为正确选用钻头及钻头对岩层适用性研究的轻型设备。     

在微型机上用逐步回归方法求钻速方程

一、前言在岩心钻探工程中，机械钻速对于确定岩石的可钻性是一个重要的参数。我国岩心钻探岩石十二级分级表就是在生产现场进行大量实际标定后所制定出来的。以机械钻速为主要指标的岩石可钻性分级表。这种用现场实际生产效果来度量岩石可钻性的办法，在钻探生产发展过程中逐渐暴露出许多缺点。当前关于岩石可钻性研究的一种趋向是利用岩石多种物理力学性质指标来表示岩石的可钻性。尽管如此，机械钻速毕竟是一个同时受到技术条件、人为因素和岩石可钻性综合影响的复杂指标，它有直观反映     

测井资料在钻速预测中的应用研究

在分析了国内外钻速预测研究现状的基础上,选择了岩石可钻性法来对胜利油田东营凹陷钻速进行预测研究,建立了声波预测钻速的钻速方程,并利用现场资料对钻速方程进行了验证,同时进行了２口井的钻速预测,预测精度达到９０％以上。     

MDES2000型微钻实验装置的研制

MDES2000型微钻实验装置可模拟真实钻进情况,可开展岩石研磨性与可钻性试验、金刚石钻头性能参数及寿命试验、优化钻进规程参数试验等室内的各种微钻实验研究工作。该实验装置可通过手动或程序控制完成模拟钻进工作,能够实现钻进过程中各项钻进参数（钻压、钻速、扭矩、转速及进尺）的监测、采集、处理及存储功能,还可建立钻进参数报表文件数据库。该实验装置对岩心钻探研究工作具有很好的实际指导意义。     

The Collimated Propagation Causes of Astrophysical and Laboratory Jets

Astronomy Reports - The use of Z-pinch facilities makes it possible to carry out well-controlled and diagnosable laboratory experiments to study laboratory jets with scaling parameters close to...     

Analysis of Flexible Pavements Reinforced with Geogrids

Effectiveness of glass fiber grids as a reinforcement of the asphalt layer in a flexible pavement system was investigated. The study involved both laboratory experimental work and computer analysis of pavement sections. Twenty flexible pavement sections (with and without glass fiber grids) were constructed and tested in the laboratory as a part of the experimental study. The laboratory-scale pavement sections were instrumented with pressure cells, displacement gages, and strain gages. Test sections were subjected to 1,000,000 load applications at a frequency of 1.2 Hz. Static loading tests were conducted at intervals of 100,000 load applications. In thirteen experiments, glass fiber grids were used as reinforcement in the asphalt layer. Several computer analyses of flexible pavement sections were performed by using the finite element method (FEM). The laboratory data were compared with results obtained from the computer analyses. Results from this study show that glass fiber grids can be used to improve the performance of flexible pavement systems. It was also observed that the inclusion of glass fiber grid in the asphalt layer provided resistance to crack propagation. Overall, the flexible pavement sections reinforced with glass fiber grids showed better performance under laboratory test conditions.     

Cuttability assessment of hard coal seams

Summary A number of field and laboratory tests have been carried out on more than 15 coal seams of compressive strengths ranging from 19 MPa to 44 MPa to evolve methods which would help in the selection of suitable coaling machines for hard coal seams. The effect of physico-mechanical properties on cuttability were studied in the laboratory for all these coal seams to identify the relevant parameters affecting the specific energy of coal cuttability. These data were subjected to regression analysis to find the best fit for estimation of laboratory specific energy of coal samples on the basis of simple laboratory and field tests for the strength parameters. Field studies were also conducted over a large number of active mechanized coal faces to study in situ cuttability along with the geo-mining conditions of the site. The field and the laboratory data so generated were correlated and an attempt is made to establish a relationship for estimating the field specific energy for a particular capacity of coaling machines by considering the geo-mining domain of the field in totality.     

Comparison of laboratory testing protocols to field observations of the weathering of sulfide-bearing mine tailings

A laboratory weathering study using a humidity cell procedure was conducted on two sulfide-bearing tailing samples from a metallurgical site in Ontario (Canada). The test was accompanied by microbiological studies to enumerate the major groups of sulfur-oxidizing bacteria and determine their potential role at different stages during the oxidation process. To evaluate the utility of this method, results were compared with those of previous laboratory and field studies on the same materials. The mineralogy of the laboratory samples differs only by the addition of a small amount of hydronium-bearing natrojarosite [(Na,H₃O)Fe₃(SO₄)₂(OH)₆] to one sample. The progress of sulfide oxidation and the rates of solute release were determined to evaluate the extent of mineral dissolution. These processes were influenced strongly by the capacity of the material to generate acidity, which was enhanced by the presence of hydronium-bearing natrojarosite. Acid-neutralization processes occurring during the laboratory tests were affected by reaction kinetics, consistent with field observations. In particular, the extent of carbonate-mineral dissolution appears to be different in the laboratory than in the field, where more prolonged rock–water interaction allowed more complete chemical equilibration. As a consequence, the capacity of this test procedure to predict weathering reactions in mine tailings is limited by its inability to reproduce the weathering sequence observed in the field. The results of the microbiological study showed that distinct groups of sulfur-oxidizing bacteria operate at different stages of the oxidative process, as was observed in field studies where tailings oxidation occurred under natural conditions, suggesting that microbiological tests performed for laboratory studies are reflective of field conditions.     

Full-scale linear cutting test in Chongqing Sandstone and the comparison with field TBM excavation performance

In this study, determination of some machine parameters and performance prediction for tunnel boring machine (TBM) are conducted based on laboratory rock cutting test. Firstly, laboratory full-scale linear cutting test is carried out using 432-mm CCS (constant cross section) disc cutter in Chongqing Sandstone. Then, the input parameters for TBM cutterhead design are extracted; some TBM specifications are determined and then compared to the manufactured values. Finally, laboratory full-scale linear cutting test results are compared with the field TBM excavation performance data collected in Chongqing Yangtze River Tunnel. Results show that laboratory full-scale linear cutting test results, combined with some engineering considerations, can be used for the preliminary and rough design of TBM machine capacity. Meanwhile, combined with some modification factors, it can also well predict the field TBM excavation performance.

     

Thermal conductivity of soft Bangkok clay from laboratory and field measurements

This paper presents the results of a study on the thermal conductivity of a soft saturated clay (Bangkok clay) carried out in relation to an investigation into using thermal treatment to enhance the consolidation process of soft soils. The thermal conductivity of clay specimens was measured in the laboratory using a steady state method (divided bar test) and a transient state method (needle probe test). In general, the laboratory test results show that the thermal conductivity increased with the increase in soil density. However, the needle probe test was found to yield greater thermal conductivities than those derived from the divided bar test. Furthermore, to assess the validity of the laboratory test results, the heat transfer results obtained from a full-scale embankment test that employed prefabricated vertical thermo-drains (PVTD) were simulated numerically using the laboratory determined thermal conductivity values. The numerical analysis indicates that the field thermal conductivity was close to the value obtained from the needle probe test. However, it was also found that the changes in thermal conductivity values obtained from the two laboratory methods did not impact significantly on heat flow behaviour, suggesting that the two methods are acceptable for characterizing the thermal conductivity of soils.     

Seismic piezocone interpretation for shear wave velocity (<Emphasis Type="Italic">V</Emphasis><Subscript>S</Subscript>) determination in the Persian Gulf

Shear wave velocity is one of the important factors representing the dynamic characteristics of soil layers. Hence, many researchers have focused their studies on determining shear wave velocity by direct field measurements or expressions developed by other soil parameters. The shear module and damping ratio of the soil layers also play a similar role in the majority of dynamic soil response analyses. Nevertheless, since they have to be measured in the laboratory by resonant column or cyclic triaxial tests on undisturbed samples, the possibility of preparing such samples and the reliability of the obtained results are of great concerns. In the present study, great effort has been made to determine the above dynamic factors by means of field data obtained from a versatile instrument, namely the seismic piezocone (SPCT_U), and to derive expressions correlating them with some parameters obtainable by much simpler instruments. The reliability of laboratory measurements on undisturbed samples is also evaluated. The seismic piezocone test apparatus has been employed to evaluate the soil properties at 1-m depth intervals by means of measuring tip resistance, sleeve resistance, pore pressure and shear wave velocity. The shear module and the damping ratio are calculated using field data. Meanwhile, in order to assess the laboratory measurements of these parameters, some resonant column tests and cyclic triaxial tests on undisturbed samples of the same soil layers have been carried out. In order to compare the field results of shear modulus and damping ratios with those obtained from laboratory tests, the influences of the soil nature and sample disturbance on the conventional laboratory methods are evaluated and discussed. The shear wave velocity is correlated to overburden pressure and the corrected tip resistance for two groups of fine soils, namely silty clays and carbonate clayey silts, which mainly cover the areas under study in this project, are located in southern parts of Iran near the Persian Gulf. According to the results of the present study, there are narrow limits of shear modulus regarding soils for which the laboratory tests and the field measurements yield approximately the same shear modulus. This limit of shear modulus is about 30–50(MPa) for clay deposits and 70–100 (MPa) for sandy deposits. Also the shear wave velocity can be calculated by a simple expression from total overburden pressure and the tip resistance of simple cone penetration test results conventionally available in many soil explorations prior to engineering practices. However, if the pore pressure inside the saturated soil deposits can be measured by a piezocone apparatus, the shear wave velocity may be calculated using another suggested equation in terms of effective overburden pressure in the present study. Regarding the shear module and the damping ratio, due to the disturbances of the stiff deposits in the sampling process and great deviations of laboratory results from field results, the laboratory measurements of these parameters out of the above limits are not recommended.     

Investigation of Various Parameters Effect on Cerchar Abrasivity Index with PFC3D Modeling

The Cerchar test is one of the appropriate and routine tests for determining the rock abrasion; but as for the costs and pin wear measurement errors in laboratory procedures and lack of access to laboratory equipment, using of numerical modeling can lead to use of greater number of samples required during the course of mechanized excavation and reduce the costs and errors in the laboratory test. In this study, the Cerchar abrasivity test was modeled using PFC3D (Particle Flow Code in 3 Dimensions) software. In order to verify the simulation results, Cerchar laboratory test results obtained by Rostami (Rock Mech Rock Eng 47(5):1905–1919, 2014) were compared with the numerical modeling results. In modeling studies, the effects of some parameters such as apply load, test speed, pin hardness and scratching distance on pin wear were investigated. As a conclusion of the study, good agreement between modeling and experimental results was obtained for a given condition. As in the experiment with various loads in both laboratory tests and modeling, with increasing applied load the Cerchar abrasivity index also increased in the experiment with Rockwell hardness HRC (An abbreviation for Rockwell Hardness measured on the C scale. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload, that on the C scale use from a indenter with 120° cone and 150 kgf load) 42.     

Slaking durability and its effect on the doline formation in the gypsum

Texture and grain size is of great importance in understanding the mechanical properties of rocks. The aim of this study was to investigate textural and slaking durability characteristics, and correlate them with the gypsum types where the dolines occurred, with particular reference to the texture and crystal size. The investigation comprised two stages: field work and laboratory testing. Initially, rock samples were obtained from various representative karstified and non-karstified locations. Thereafter, mineralogical, physical and slaking durability characteristics of the gypsum samples were determined by means of laboratory testing. After the field and laboratory works, the geological, mineralogical and slaking durability characteristics of the study area gypsum were reviewed and discussed from the point of view of doline formation. Results showed that fine grain sized alabastrine gypsum tends to be karstified and leads to doline formation. This is closely related to the crystal size, texture and attributable to the slaking durability of the gypsum. Consequently, the results demonstrate that the texture, especially crystal size, and effective porosity are important parameters controlling the slake durability of the gypsum and doline formation.     

A laboratory and full-scale study on the fragmentation behavior of rocks

Rock fines produced in rock blasting and crushing processes is a major problem for aggregate producers. Laboratory and full-scale studies were carried out to explore the possible relationship between fines production and water content of rock material. The Brazilian tensile test was selected for the laboratory study while a cone crusher machine was employed for the full-scale trials. Results of the laboratory work showed that the percentage of fines fraction produced was a function of the type of rock tested and the tensile strength of individual specimens. Different rocks produced various amounts of fines, but for the rocks investigated, a correlation between its strength and its fines generation could be attained. The influence of water content on production of fines was also examined and showed that increased water content reduces both tensile strength and fines generation in the laboratory. The impact of water content on aggregate production was also studied in full-scale but the results were not as clear as those of the laboratory tests.