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1.
针对煤矿井下穿层钻孔硬岩钻进效率低的难题,基于冲击回转钻进机理和Wassara高压液动冲击器主要特点,分析柱齿在冲击荷载下形成的破碎坑形态,并将其划分为崩解区、密实区、开裂区和弹性区。在此基础之上,对柱齿连续破岩的大间隔冲击和小间隔冲击2种情况进行过程分析,结合淮南潘三矿现场试验条件讨论高压液动冲击回转钻进工艺参数,优选高压液动冲击回转钻进配套钻机、冲击器、钻杆、钻头和清水泵,及主要技术参数。试验结果表明：当清水压力在15 MPa以上时,高压液动冲击回转钻进的平均机械钻速为24.67 m/h,与采用该技术之前的8.48 m/h机械钻速相比提高了约1.9倍;并采用回归分析拟合得到机械钻速与水压之间的线性关系,经过数理统计的F检验,F=8.82大于F0.05(1,7),验证了回归结果是显著的,机械钻速随水压的增大而线性增大。高压液动冲击回转钻进技术可有效提高煤矿井下硬岩层钻进效率,保障煤矿安全高效生产。 相似文献
2.
This paper presents a novel dynamical model to analyze the long‐term response of a percussive drilling system. This departs from existing approaches that usually consider a single activation and bit/rock interaction cycle for the analysis of the process performance. The proposed model integrates the axial dynamics of an elastic piston and an elastic drill bit, a motion‐dependent pressure law to drive the piston, and a generalized bit/rock interaction law representative of the dynamic indentation taking place at the bit/rock interface. It applies to down‐the‐hole percussive drilling as well as top‐hole, with minor modifications. The model does not account for the angular motion or the hole cleaning, however. The model is first formulated mathematically; then, a finite‐dimensional approximation is proposed for computations. Numerical analyses of the model response, for a low‐size down‐the‐hole percussive system, follow. The period‐1 stationary response for the reference configuration is studied in detail, and parametric analyses assessing the influence on the rate of penetration of the bit/rock interaction parameters, the feed force, and the percussive activation parameters are conducted. These analyses reveal that the multiscale nature of the process is well captured by the model and recover expected trends for the influence of the parameters. They also suggest that a significant increase of the penetration rate can be achieved by increasing the percussive frequency. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
3.
Iron sulfide was synthesized by reacting aqueous solutions of sodium sulfide and ferrous chloride for 3 days. By X-ray powder diffraction (XRPD), the resultant phase was determined to be primarily nanocrystalline mackinawite (space group: P4/ nmm) with unit cell parameters a = b = 3.67 Å and c = 5.20 Å. Iron K-edge XAS analysis also indicated the dominance of mackinawite. Lattice expansion of synthetic mackinawite was observed along the c-axis relative to well-crystalline mackinawite. Compared with relatively short-aged phase, the mackinawite prepared here was composed of larger crystallites with less elongated lattice spacings. The direct observation of lattice fringes by HR-TEM verified the applicability of Bragg diffraction in determining the lattice parameters of nanocrystalline mackinawite from XRPD patterns. Estimated particle size and external specific surface area (SSAext) of nanocrystalline mackinawite varied significantly with the methods used. The use of Scherrer equation for measuring crystallite size based on XRPD patterns is limited by uncertainty of the Scherrer constant (K) due to the presence of polydisperse particles. The presence of polycrystalline particles may also lead to inaccurate particle size estimation by Scherrer equation, given that crystallite and particle sizes are not equivalent. The TEM observation yielded the smallest SSAext of 103 m2/g. This measurement was not representative of dispersed particles due to particle aggregation from drying during sample preparation. In contrast, EGME method and PCS measurement yielded higher SSAext (276-345 m2/g by EGME and 424 ± 130 m2/g by PCS). These were in reasonable agreement with those previously measured by the methods insensitive to particle aggregation. 相似文献
4.
利用神经网络法预测风动潜孔锤钻速 总被引：4，自引：1，他引：3
风动潜孔锤钻进在钻效方面有着传统钻进方法无可比拟的优势。以往的钻速预测主要是针对回转钻进,而准确预测风动潜孔锤钻速则更具有现实意义,更有利于合理制定钻井计划。利用有多隐层的BP神经网络原理,综合考虑钻压、转速、风压、风量、钻井深度、钻头工作时间等各方面参数对钻速的影响,研究了贯通式潜孔锤冲击回转钻井钻速的预测方法,并对现场实际钻井作业进行了预测。预测结果与现场实际情况能很好地吻合。同时又以预测结果为基础,优选钻进参数以指导施工。 相似文献
5.
G. Draper 《Tectonophysics》1976,35(4):7-13
Shear strain γ in brittle fault zones is related to final and initial grain size parameters, df and di, respectively, by an expression of the form:
where μk the coefficient of kinetic friction of crushed rock and σn the normal stress across the zone at the time of faulting.Technological literature suggests that ƒ(df, di) may be given by 10
, where Wi is a material constant. The resulting relationship between shear strain and grain size seems to be compatible with existing experimental data. 相似文献
6.
Xiaobin Ding Lianyang Zhang Hehua Zhu Qi Zhang 《Rock Mechanics and Rock Engineering》2014,47(6):2139-2156
This paper investigates the effect of model scale and particle size distribution on the simulated macroscopic mechanical properties, unconfined compressive strength (UCS), Young’s modulus and Poisson’s ratio, using the three-dimensional particle flow code (PFC3D). Four different maximum to minimum particle size (d max/d min) ratios, all having a continuous uniform size distribution, were considered and seven model (specimen) diameter to median particle size ratios (L/d) were studied for each d max/d min ratio. The results indicate that the coefficients of variation (COVs) of the simulated macroscopic mechanical properties using PFC3D decrease significantly as L/d increases. The results also indicate that the simulated mechanical properties using PFC3D show much lower COVs than those in PFC2D at all model scales. The average simulated UCS and Young’s modulus using the default PFC3D procedure keep increasing with larger L/d, although the rate of increase decreases with larger L/d. This is mainly caused by the decrease of model porosity with larger L/d associated with the default PFC3D method and the better balanced contact force chains at larger L/d. After the effect of model porosity is eliminated, the results on the net model scale effect indicate that the average simulated UCS still increases with larger L/d but the rate is much smaller, the average simulated Young’s modulus decreases with larger L/d instead, and the average simulated Poisson’s ratio versus L/d relationship remains about the same. Particle size distribution also affects the simulated macroscopic mechanical properties, larger d max/d min leading to greater average simulated UCS and Young’s modulus and smaller average simulated Poisson’s ratio, and the changing rates become smaller at larger d max/d min. This study shows that it is important to properly consider the effect of model scale and particle size distribution in PFC3D simulations. 相似文献
7.
Anurag Gupta Somnath Chattopadhyaya Sergej Hloch 《Rock Mechanics and Rock Engineering》2013,46(1):169-177
Mining and petroleum drill bits are subjected to highly abrasive rock and high-velocity fluids that cause severe wear and erosion in service. To augment the rate of penetration and minimize the cost per foot, such drill bits are subjected to increasing rotary speeds and weight. A rotary/percussive drill typically hits the rock 50 times per second with hydraulic impact pressure of about 170–200 bar and feed pressure of about 90–100 bar, while rotating at 75–200 rpm. The drill rig delivers a high-velocity flow of drilling fluid onto the rock surface to dislodge cuttings and cool the bit. The impingement of high-velocity drilling fluid with entrained cuttings accelerates the erosion rate of the bit. Also, high service temperature contributes to softening of the rock for increased penetration. Hence, there is a need to optimize the drilling process and balance the wear rate and penetration rate simultaneously. This paper presents an experimental scanning electron microscopy (SEM) study of electroplated (nickel-bonded) diamond drills for different wear modes. 相似文献
8.
X. Li T. S. Lok D. A. Summers G. Rupert J. Tyler 《Geotechnical and Geological Engineering》2001,19(2):119-136
Experiments have been conducted using an impact method with drop-hammers to obtain the required signals so that a detailed analysis of these data could be undertaken to quantify the drillability index of rocks. The dynamic stress waveform or reflected energy from the rock-drill bit interface is represented as a drillability index. This information enables the assessment of the characteristics of the rock under the bit. The results show that neither the amplitude nor the frequency spectra of the reflected stress wave significantly changes with the type of rock tested. However, the energy reflection coefficient varies with rock hardness. In the process of drilling the rocks, the energy reflection coefficient can increase by approximately 20% when the hardness or penetration resistance index of rock is doubled. This investigation confirmed the variation of reflected energy of rocks. For a single sharp or domed indentor, energy reflection decreases with penetration resistance index of the rock while it increases with this index in actual drilling or testing of percussive bits. In drill bit design and in tests for using a single indentor, a reasonable indentor shape should be adopted to correspond to a high energy reflection coefficient. By contrast, the energy reflection from a drill system or percussive bit should be minimised in practice. 相似文献
9.
依据烃源岩地球化学实验手段和油气地化理论,对辽东湾地区辽中凹陷东营组东二下段(Ed2-1)和东三段(Ed3)地层进行了有机地化分析。在实验获取总有机碳(TOC)、生烃潜量(S1+S2)、氢指数(IH)、氢碳比(H/C)、氧碳比(O/C)、最大热解峰温(Tmax)、镜质体反射率(Ro)等有机地化参数的基础上,对有机质丰度、类型、成熟度等进行了系统分析,同时对东营组烃源岩进行了综合评价。研究表明,东二下段S1+S2集中在0~3 mg/g,TOC集中在0%~1.5%;东三段S1+S2集中分布在4~9 mg/g之间,TOC集中分布在1%~1.25%。东二下段有机质类型主要是III型,东三段有机质类型为II1、II2型。东二下段Ro0.5,东三段Ro0.5,并且随着深度的增加东三段烃源岩Ro相应的增加。Tmax随着深度的增加呈现出先增加后减少的异常现象,该种异常现象出现的原因与烃源岩有机质类型和有机质丰度之间存在很大关联。 相似文献
10.
The aim of this study is to numerically model the fracture system at percussive drilling. Because of the complex behavior of rock materials, a continuum approach is employed relying upon a plasticity model with yield surface locus as a quadratic function of the mean pressure in the principal stress space coupled with an anisotropic damage model. In particular, Bohus granite rock is investigated, and the material parameters are defined based on previous experiments. This includes different tests such as direct tension and compression, three‐point bending, and quasi‐oedometric tests to investigate the material behavior at both tension and confined compression stress states. The equation of motion is discretized using a finite element approach, and the explicit time integration method is employed. Edge‐on impact tests are performed, and the results are used to validate the numerical model. The percussive drilling problem is then modeled in 3D, and the bit‐rock interaction is considered using contact mechanics. The fracture mechanism in the rock and the bit penetration‐ resisting force response are realistically captured by the numerical model. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
11.
A.H. Englert R.T. Rodrigues J. Rubio 《International Journal of Mineral Processing》2009,90(1-4):27-34
Experimental studies concerning the dissolved air flotation (DAF) of fine (dp < 100 μm) quartz particles, using two different flotation cells (setups), are presented. Pure and well characterised quartz samples were treated with a commercial amine as collector prior to flotation and bubbles were characterised by the LTM-BSizer technique. Bubble size distribution showed 71% (by volume) and 94% (by number) of the bubbles having sizes (db) lower than 100 μm (i.e. microbubbles). The Sauter and arithmetic mean diameters were 79 μm and 56 μm, respectively, for the bubbles generated at 300 kPa (gauge) saturation pressure (after 30 minute saturation time). Quartz particle size distribution (obtained by laser diffraction) showed a volume-moment diameter of 13 μm. The Rosin–Rammler–Bennett, Gates–Gaudin–Schumann and log-normal distribution functions were well fitted (R2 > 0.96) to the bubble size distribution and quartz particle size distribution data. Values of total quartz recovery ranging from 6% to 53% (by mass) were obtained for the DAF experiments under different collector concentrations (up to 2 mg g− 1), with an optimal collector concentration found at 1 mg g− 1. These results are significant considering that 27% (by volume) of the quartz particles are ultrafine (dp < 5 μm), demonstrating the widely-known efficiency of DAF to remove small particles when applied in the field of water and wastewater treatment. The true flotation behaviour, as a function of particle diameter (dp), exhibits a local minimum when particles are approximately 3–5 μm in size. The results contribute to the discussion in the literature about the existence of such a minimum, which is generally interpreted as a change in the mechanism of particle collection from convection (collision) to diffusion at lower particle sizes. 相似文献
12.
F. N. Okonta 《Rock Mechanics and Rock Engineering》2014,47(4):1335-1344
Sub-angular-shaped aggregates are used as rail foundation ballasts and must remain sub-angular during their service life time to maintain particle–particle interlocking, in order to ensure the stability of the rail line and prevent accidents by derailment. Here, the screening of dolerite quarry aggregates for use as railway foundation ballasts was investigated by employing simple digital image and chart methods. The average particle size (d 50), flakiness index (FI), Los Angeles abrasion index (LAAI), sphericity (SPH) and roundness (RND) were determined for two batches of dolerite ballasts from the Rooikraal quarry in Johannesburg and Ngagane quarry in Newcastle. Thirty samples from each of the two batches of ballast were analysed. The ballasts were progressively abraded using a Los Angeles abrasion device and were analysed after each cycle of abrasion. A decrease in d 50 and an increase in FI with increased number of abrasion cycles were observed for both batches of dolerite ballast. The difference in the chart and digital image values of RND and SPH were marginal before abrasion; however, these differences increased with each abrasion cycle. The LAAI, d 50, mean RND and mean SPH correlated significantly and were found to have high regression coefficients. Thus, statistical models are proposed for the non-destructive routine screening of in-place ballasts in order to track marginal changes in aggregate shapes, facilitate ballast replacement programmes and avoid rail line instability. 相似文献
13.
Effects of aeration rate, slurry flow rate, stirring rate, pulp density, and particle size on the residence time distribution of a solid in a continuously operated flotation cell under non-flotation conditions (no frother, no concentrate removal) have been examined. The mixing behaviour of the solid in the cell has been quantitatively analysed using a multiple parameter approach. The results indicate that only a part of the cell volume behaves as a perfect mixer, the remaining being dead. The exit residence time distribution E(t) and the mean residence time (
) of solid are described by: and where Q is the volumetric slurry flow rate. For the variables ranges examined, it is observed that the aeration does not have any significant effect on the mixing behaviour, Veff increases with increasing slurry flow rate and stirring rate but decreases with increasing pulp density. The mean residence time, on the other hand, increases with increasing stirring rate, decreases with increasing slurry flow rate and pulp density, and exhibits a maximum with respect to particle size. Following empirical equation correlating the effective volume of the cell with the operating variables for a unisize feed is obtained: where B is the weight fraction of solid in the pulp. 相似文献
14.
Simple axi-symmetric uni-axial compression tests have been realized on dry loose samples of glass beads (diameters d: d=0.2 ± 0.05 mm, 0.75 ± 0.1 mm, or 3 mm) and on Hostun sand under small lateral confinement, σ3<60 kPa, using different sample sizes. The experiments with the two smallest spheres (d=0.2 and 0.75 mm) exhibit stick-slips, which are characterized by (i) a rapid release Δq of the deviatoric stress q and by (ii) the strain Δε1 separating two events. The samples which exhibit stick-slip also present a weakening of strength q(ε1) as the rate of deformation dε1/dt is increased. No stick-slip is generated during the first part of the q−ε1 curve, i.e. when q grows fast with ε1. Four different parameters helped us determine the statistics of Δq and Δε: the lateral pressure σ3′, the rate of deformation dε1/dt, the sample height H, and the diameter D. The statistics do not depend on rate history. They look like exponentials in small samples and/or in (large sample+fast dε1/dt), and they look like Poissonian or Gaussian in (Large sample+small dε1/dt). This change in statistics is attributed to a varying of triggering process starting from a single random event in small samples to multiple random events. We have interpreted this change of statistics as due to some finite size effect so that the representative elementary volume shall contain at least (200)3 grains. Localization of deformation is visible at the end of compression but cannot be detected from stick-slip statistics nor from q vs ε curve. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
15.
The correlations between three different methods of measuring brittleness and both drillability and borability were statistically investigated using the raw data obtained from the experimental works of different researchers.
Strong exponential relationships between the penetration rates of tunnel boring machine (TBM) and the brittleness of B1 (the ratio of compressive strength to tensile strength) and B2 (the ratio of compressive strength minus tensile strength to compressive strength plus tensile strength) were found. There is no correlation between the penetration rates of the diamond drilling tool and the brittleness values. Strong exponential correlations exist between the penetration rates of rotary drills and the brittleness of B1 and B2. However, no correlation between the penetration rate of rotary drills and the brittleness of B3 (the product of percentage of fines in impact strength test and compressive strength) was found. The penetration rate of percussive drills does not exhibit a correlation with the brittleness of B1 and B2, but the penetration rate of percussive drills is strongly correlated with the brittleness of B3.
It was concluded that each method of measuring brittleness has its usage in rock excavation depending on practical utility. 相似文献
16.
岩碴是岩-机作用的直接产物,也是评价隧道掘进机（TBM）破岩效率和优化TBM掘进参数的有效指标。依托兰州水源地建设工程和龙岩万安溪引水工程,开展不同岩性条件下TBM岩碴筛分试验,得到了岩碴粒径分布规律。基于新表面理论,从滚刀破岩能量转化角度出发,提出了一种新的TBM破岩效率评价指标。基于岩碴粒径分布规律和TBM掘进参数统计,探讨了新表面理论指标与比能、岩碴粗糙度指数之间的关系,指出了新表面理论指标在反映岩碴破碎程度和评价TBM破岩效率方面的优势。对新表面理论指标与TBM掘进推力以及刀间距s与贯入度p的比值进行回归分析,得到了硬岩（围岩等级为Ⅱ级）和软岩（围岩等级为III级）掘进条件下的TBM最优掘进推力和s/p取值区间。研究表明：（1）新表面理论指标符合岩石破碎学原理,可准确评价TBM破岩效率。岩碴越是破碎,新表面理论指标越大,掘进能耗越高,此时TBM破岩效率相对较低。（2）新表面理论指标与比能、岩碴粗糙度指数均具有良好的线性相关关系。岩碴越是破碎,破碎单位体积岩石的能量消耗越大,新表面理论指标越大,对应的粗糙度指数越小。软岩掘进条件下TBM掘进比能低于硬岩,而岩碴破碎程度高于硬岩。（... 相似文献
17.
石英是热液矿床重要的找矿标志,也是影响页岩气储层可压裂性评价的关键性因素,目前主要利用X射线衍射方法和扫描电镜矿物定量分析方法进行实验室内石英定量分析。为满足野外钻井现场进行快速、大批量矿物定量分析的需求,本文以羌塘盆地泥岩、砂岩、砾岩、灰岩和白云岩等沉积岩样品为研究对象,应用热红外反射光谱技术和综合自动矿物岩石学(QEMSCAN)矿物定量分析技术,开展了石英热红外反射光谱含量评价研究。结果表明:石英在8625nm、12640nm和14450nm三个特征中心波长位置的相对深度(D_(8625)、D_(12640)、D_(14450))可以用来区分陆源碎屑岩和碳酸盐岩,当D_(8625)0.14或D_(12640)0.02或D_(14450)0.02时,样品岩性主要为陆源碎屑岩,否则主要为碳酸盐岩。此外,D_(8625)、D_(12640)、D_(14450)三个石英光谱特征参数均与石英含量具有高度的相关性,均可以利用最小二乘法构建石英含量评价模型。以拟合优度(R~2)和均方根误差(RMSE)两个指标评价三个模型的精度,其中根据D_(8625)参数建立的石英含量估算模型的拟合优度最大(R~2=0.9237),且均方根误差最小(RMSE=8.51),基于此认为D_(8625)石英光谱参数可以作为评价石英含量的最优光谱指标。本文基于热红外反射光谱技术建立的该种野外快速估算钻井中石英含量的方法,为热液矿床找矿勘查和页岩气勘探开发提供了借鉴和参考。 相似文献
18.
Timotej Verbovšek 《Environmental Geology》2008,53(6):1173-1182
Diagenetic effects upon the hydraulic parameters of dolomite aquifers were examined. Results indicate that dolomites affected
only by late (burial) diagenesis are economically more interesting to exploit than those formed first by early and then also
affected by late diagenesis, as the values of most studied hydraulic parameters (transmissivity, specific capacity, linearized
specific capacity and maximum yields) are higher in the former group. Data were collected from the hydrogeological reports
of 298 wells in dolomites from Permian to Cretaceous age in Slovenia, classified in a relational hydrogeological database
and analyzed by statistical methods. The studied parameters are hydraulic conductivity K, transmissivity T, specific capacity q (=Q/s), linearized specific capacity Ql (=q/d) and maximum yields Q
max. Values of the studied parameters are distributed log-normally according to most normality tests and span several orders
of magnitude. Statistical tests show significant differences between the “late” and “early + late” groups for parameters q, Ql and T, and non-significant differences for K and Q
max. 相似文献
19.
高转速钻进时金刚石钻头磨损的试验研究进展 总被引：4，自引：2，他引：2
讨论了金刚石钻进中提高机械钻速和降低钻探磨损问题 ;探讨了这两个技术指标与钻压、转速的关系 ;提出了表示机械钻速和钻头胎体磨损关系的钻探效果指标 ,并根据后者确定出了规程参数最优值 相似文献
20.
《Sedimentology》2018,65(6):1859-1874
Ripples are prevalent in aeolian landscapes. Many researchers have focused on the shape and formation of sand ripples, but few have studied the differences in the particle size of sand on crests and in troughs along bed, especially the variations caused by changes in friction velocity and the wind‐blowing duration. A particle size of 158 μm (d ) was used to create aeolian ripples in a wind tunnel under four friction velocities (u *) with different wind duration times (t ). Samples were collected from the surfaces of ripple crests and troughs, respectively, at seven sites, and particle sizes were measured using a Malvern Mastersizer 2000. The main results were: (i) The particle size distributions of sand in troughs are unimodal with slight variations of particle size parameters, including mean particle size, standard deviation, skewness and kurtosis, etc., under different conditions, while these particle size parameters of sand on crests change with friction velocity and deflation time. Moreover, some of the particle distribution curves for the sand on crests do not follow typical unimodal curves. (ii) With increasing friction velocity or deflation duration, the sand on the crests shows a coarsening process relative to those on the bed surface. The particle size of sand on crests at a 1 m bed increases linearly with friction velocity (d = 344·27 + 34·54 u *) at a given wind‐blowing duration. The particle sizes of sand on crests at 1 m, 2 m and 4 m beds increase with a power‐law relationship (d = a + t b, where a and b are fitting parameters) with deflation time at a given friction velocity. (iii) The probability cumulative curves of sand showed a three‐section pattern in troughs and on most of the crests but a four‐section pattern at crest locations due to increased influence by friction velocity and deflation time. The proportions of the sediment moved by suspension, saltation and creep in the three‐section pattern were within the ranges of 0·2% to 2·0%, 97·0% to 98·9%, and 0·8% to 3·0%, respectively. For the four‐section pattern, suspension accounted for 0·3% and 3·0%, and the proportion of creep increased with friction velocity and deflation time, while saltation decreased accordingly. Although these results require additional validation, they help to advance current understanding of the grain‐size characteristics of aeolian ripples. 相似文献