共查询到20条相似文献，搜索用时 31 毫秒
1.
Gajanan Kapure Chandrakala KariS. Mohan Rao N.D. Rao 《International Journal of Mineral Processing》2007
The Floatex density separator (FDS) is an industrial separator and works on the principle of hindered settling where the settling rate of a particle in suspension is affected by nearby particles. This phenomenon of hindered settling has been described by various authors using the concept of particle slip velocity. The feasibility of one such slip velocity model proposed by Galvin et al. to predict the separation of chromite in a plant scale FDS was examined. Previously this model was validated only at lab scale with synthetic mixture of various density particles. In order to use this model, the feed chromite ore was characterized and quantified into different density mineral classes and their percentages were estimated by using mineralogical grain count method. The performance of FDS was then predicted using slip velocity model in terms of weight recoveries and composition of different minerals in the FDS underflow product. 相似文献
2.
倾斜基岩上的边坡破坏模式和稳定性分析 总被引：6，自引：0，他引：6
应用离心模型试验对工程中被颇为关注的带有与边坡走向一致的倾斜基岩面,且在该基岩面存在软弱夹层的边坡的稳定性和破坏模式进行了比较详细地研究,并用极限平衡分析方法对试验结果进行了计算分析。模型试验结果表明,该类边坡失稳时,紧贴岩面的软弱夹层就成为滑动破坏面,因而边坡整体沿基岩面向下滑动,且侧向水平位移各处基本一致,表现出典型的平移滑动破坏模式。将稳定安全系数的实测结果与按平移滑动破坏模式的极限平衡分析方法的计算结果相比较后发现,两者相当地吻合,证实了按平移滑动破坏模式所作的极限平衡分析,能良好地预测边坡平移滑动破坏情形下的稳定安全系数。 相似文献
3.
海原断裂带库仑应力积累 总被引：1，自引：0，他引：1
用中国地壳运动观测网络区域站在海原断裂带附近的所有观测数据及跨断裂GPS剖面观测数据作为约束, 用Smith3D体力模型反演了海原断裂带断层滑动速率和断层闭锁深度, 计算了库仑应力积累率和地震矩积累率.采用遗传算法拟合GPS水平运动速度场, 拟合的最后残差均方根为1.2mm/a.反演结果为: 第一段毛毛山断裂左旋走滑运动速率为3.6mm/a, 闭锁深度为22km; 第二段老虎山断裂左旋走滑速率为10.5mm/a, 闭锁深度为11.4km; 第三、四、五段(海原断裂带西段、中段和东段) 滑动速率依次为3.5mm/a、5.8mm/a、5.7mm/a, 闭锁深度依次为8.5km、3.6km、4.3km.海原断裂带库仑应力积累率为0.48~1.59MPa/100a, 毛毛山断裂地震矩积累率较大, 但库仑应力积累率较小; 老虎山断裂库仑应力积累率和地震矩积累率均比较大; 海原断裂带(狭义) 中西段库仑应力积累率最大. 相似文献
4.
Linear anisotropic elasticity has been applied to interpret the dislocation stability and ease of slip in wadsleyite. It
is shown that wadsleyite is very isotropic from the elastic point of view. The influence of crystal chemistry and bonding
on the choice of the slip plane is discussed. It is shown that slip is predominantly achieved on planes that do not shear
Si–O bonds. It is suggested that dissociation of dislocations is essential in determining the ease of slip among the various
slip systems.
Received: 15 July 2002 / Accepted: 14 February 2003
Acknowledgements High-pressure experiments were performed at the Bayerisches Geoinstitut under the EU IHP – Access to Research Infrastructures
Programme (Contract no. HPRI-1999-CT-00004 to D.C. Rubie). Enlightening discussions with A. Coujou and J. Rabier are gratefully
acknowledged. 相似文献
5.
Sanjeev Anand Sahu Soniya Chaudhary Pradeep Kumar Saroj Amares Chattopadhyay 《Arabian Journal of Geosciences》2017,10(5):120
The study of surface waves (Rayleigh wave) finds their virtuous applications in a numerous geological and geophysical fields including water, oil, gas, and other subsurface geological probing and exploration. The present paper efforts to investigate the influence of initial stress, Earth magnetism, and gravity on propagation of Rayleigh waves. Considered model is consist of a liquid layer lying over a magnetoelastic orthotropic half-space under self-weight and initial stress. Method of separation of variable is used to solve the equation of motion. Solutions of governing equations are obtained in terms of displacement. Frequency relation for Rayleigh wave has been obtained and matched with classical Rayleigh wave equation. In addition to classical case, some existing results have been deduced as particular case of the present study. Obtained results have been shown through numerical illustrations. It is found that the considered parameters (initial stress, Earth magnetism, and gravity) have prominent effect on phase velocity of Rayleigh wave. Graphical representations have been made to exhibit the velocity profile of Rayleigh waves for different cases with the help of MATHEMATICA. The present study may be useful for seismologists and engineers who are concern with applications of wave propagation in magnetoelastic orthotropic medium. 相似文献
6.
Wang Jianfeng 《中国地质大学学报(英文版)》1998,9(2):2
ＩＮＴＲＯＤＵＣＴＩＯＮＤｅｓｐｉｔｅｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｅｌａｓｔｉｃ－ｐｌａｓｔｉｃ－ｖｉｓｃｏｕｓｎｕｍｅｒｉ－ｃａｌｍｅｔｈｏｄｆｏｒｔｈｅａｎａｌｙｓｉｓｏｆｓｌｏｐｅｓ,ｔｒａｄｉｔｉｏｎａｌｔｅｃｈｎｉｑｕｅｓｂａｓｅｄｏｎ... 相似文献
7.
《Geomechanics and Geoengineering》2013,8(2):171-174
This paper presents the results from discrete element modelling (DEM) of an idealised (sand) asphalt mixture under constant strain rate (velocity) compressive loading using the Burgers viscoelastic model. Using dimensional analysis it is shown that the effect of scaling applied velocity is the same as that of scaling both viscosities in the Burgers model by the same factor. This has been shown to be the case for a bonded aggregate, and it also has been shown to be applicable even when bond breakage occurs within the sample. This scaling method will be of great benefit in modelling tests on asphalt under different constant strain rates, simply by scaling both viscosities to minimise computational time. 相似文献
8.
The fluidization technique has been in use for particulate material processing operations for many years. It has been widely believed that the ratio of size and density of the particulate components controls the separation efficiency. In this paper, it is demonstrated that fluid velocity during fluidization could assume an overriding significance when an improvement in separation efficiency is required. This was at first experimentally established by analyzing simpler particulate systems, and later a simulation scheme was adopted to study a wider range of particulate systems. The numerical scheme known as the discrete element method (DEM), that incorporates both the solid- and hydro-dynamic components of the interactive forces, served as an important tool in understanding the separation behavior of binary particulate systems in fluidized beds. It has been established that mere fluidization does not necessarily guarantee an optimal separation, especially when the particles differ widely in density and size. 相似文献
9.
This paper is devoted to modeling of the dynamics of the temperature regime of mud volcano gryphons. The model is elaborated
on the basis of a nonstationary equation of thermal conductivity with a convective component and describes well the observed
regularities of thermal regime of South Sakhalin mud volcano gryphons. It is shown that anomalous changes in the temperature
of the water-mud mixture after the Gornozavodsk and Nevelsk earthquakes in 2006–2007 are caused by variations in motion velocity
of the mixture in the supply pipes of gryphons. It also has been shown that influx of deep geofluids cannot be considered
as the main reason for thermal anomalies. 相似文献
10.
Decomposition and Evolution of Intracontinental Strike-Slip Faults in Eastern Tibetan Plateau 总被引：2，自引：0，他引：2
Little attention had been paid to the intracontinental strike-slip faults of the Tibetan Plateau. Since the discovery of the Longriba fault using re-measured GPS data in 2003, an increasing amount of attention has been paid to this neglected fault. The local relief and transverse swath profile show that the Longriba fault is the boundary line that separates the high and flat tomography of the Tibet plateau from the high and precipitous tomography of Orogen. In addition, GPS data shows that the Longriba fault is the boundary line where the migratory direction of the Bayan Har block changed from eastward to southeastward. The GPS data shows that the Longriba fault is the boundary fault of the sub-blocks of the eastern Bayan Har block. We built three-dimensional models containing the Longriba fault and the middle segment of the Longmenshan fault, across the Bayan Har block and the Sichuan Basin. A nonlinear finite element method was used to simulate the fault behavior and the block deformation of the Eastern Tibetan Plateau. The results show that the low resistivity and low velocity layer acts as a detachment layer, which causes the overlying blocks to move southeastward. The detachment layer also controls the vertical and horizontal deformation of the rigid Bayan Har block and leads to accumulation strain on the edge of the layer where the Longmenshan thrust is located. After a sufficient amount of strain has been accumulated on the Longmenshan fault, a large earthquake occurs, such as the 2008 Wenchuan earthquake. The strike slip activity of the Longriba fault, which is above the low resistivity and low velocity layer, partitions the lateral displacements of the Bayan Har block and adjusts the direction of motion of the Bayan Har block, from the eastward moving Ahba sub-block in the west to southeastward moving Longmenshan sub-block in the east. 相似文献
11.
In the present paper, soil-structure interaction analysis of an infinite beam resting on extensible geosynthetic reinforced
earth beds has been carried out for an applied load moving with constant velocity. The viscous damping of the soil-foundation
system has been given due consideration in the analytical procedure. The infinite beam has been treated as resting on a granular
fill layer overlying the naturally occurring weak soil layer. Geosynthetic layer has been provided in the granular fill layer
and has been considered as extensible. This extensible nature has been incorporated with the help of no slip and the compatibility
conditions at the interface between reinforcing layer and the neighboring soil. These conditions help in eliminating the two
interfacial shear stress parameters and in considering the tensile modulus of geosynthetic layer in the analysis. The influence
of various parameters, like magnitude and velocity of applied moving load, viscous damping, relative stiffness of granular
fill and tensile modulus of geosynthetic layer, on the response of soil-foundation system has been studied. It has been observed
that all these parameters affect the response significantly, however, the effect of velocity of moving load and viscous damping
has been found to be more significant especially at higher velocities. 相似文献
12.
13.
14.
基于遍布节理模型的边坡稳定性强度折减法分析 总被引：10，自引：4，他引：6
采用非线性数值分析方法分析边坡稳定性问题时,强度折减法因其具有较多的优点而得到广泛应用。岩土体一般采用理想弹塑性模型,屈服准则为广义米赛斯准则。对于密集节理岩质边坡稳定性问题,采用遍布节理模型可同时考虑岩块和节理属性,更符合岩体状态及工程实际,认为岩体经强度折减后潜在破坏可能首先出现在岩体中或沿节理面或二者同时破坏。结合工程实例,基于遍布节理模型的强度折减法计算结果表明,潜在滑移面为折线型滑面,下部潜在滑移面倾角与节理面等效内摩擦角基本一致,上部潜在滑移面与岩体拉破坏相关;节理倾角与边坡安全系数、潜在滑动范围密切相关,陡倾角节理对边坡稳定性影响较小。通过对边坡失稳判据和边坡滑移面确定的探讨,认为以力或位移不收敛作为边坡失稳判据是适当的,而边坡的剪应变速率物理意义十分明确,适于作为边坡潜在滑移面的确定依据。 相似文献
15.
Earthquakes are recognized as resulting from a stick–slip frictional instability along faults. Based on the node‐to‐point contact element strategy (an arbitrarily shaped contact element strategy applied with the static‐explicit algorithm for modelling non‐linear frictional contact problems proposed by authors), a finite element code for modelling the 3‐D non‐linear friction contact between deformable bodies has been developed and extended here to analyse the non‐linear stick–slip frictional instability between deformable rocks with a rate‐ and state‐dependent friction law. A typical fault bend model is taken as an application example to be analysed here. The variations of the normal contact force, the frictional force, the transition of stick–slip instable state and the related relative slip velocity along the fault between the deformable rocks and the stress evolution in the total bodies during the different stages are investigated, respectively. The calculated results demonstrate the usefulness of this code for simulating the non‐linear frictional instability between deformable rocks. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
16.
建立了管缝式锚杆在拉拔荷载作用下的受力分析模型,该模型能够反映锚杆破坏的渐进过程。分析表明,在拉拔荷载作用下管缝式锚杆在荷载作用点最先发生相对滑移,且随着荷载的增加滑移段的长度逐渐增加,直到整根锚杆与围岩发生相对滑移。根据能量守恒原理得到了管缝式锚杆在安装入钻孔后对围岩径向作用力的计算公式。对管缝式锚杆进行了非局部摩擦分析,得到了基于非局部摩擦模型的管缝式锚杆界面剪应力分布。研究了管缝式锚杆直径对锚杆界面剪应力分布的影响,同时得到了锚杆最大抗拉拔力与锚杆长度之间的关系。将理论模型预测值与试验结果对比,验证了理论模型的有效性。 相似文献
17.
Rock friction varies as a function of mainly four parameters that are waiting time and velocity of motion between two frictional surfaces, surface roughness and normal stress. In this paper, a study on former two aspects of rock frictional behaviour has been attempted for granitic rock surface. In one experiment, waiting time for which the two surfaces remain in contact is increased from 20 seconds to 18 hours. In the second experiment, waiting time is kept constant for a series of rock slip experiments where the velocity is increased from 10??m/sec to 350??m/sec. The value of critical velocity is obtained from transformation of the stick slip motion to steady motion occurs. The relation of coefficients of dynamic and static friction with increasing velocity of motion is studied and these are used to calculate the frictional constants, namely ??a?? and ??b?? specific to the chosen simulation type. 相似文献
18.
对屈服条件与屈服函数的极值条件进行了讨论,在不需要流动法则的情况下建立了速度方程。平衡方程、屈服条件与屈服函数的极值条件、速度方程就是土体极限分析的基本方程。这样,对荷载、速度边界条件（包括荷载与速度边界同时存在）,均构成了完备的极限平衡问题。对边坡稳定问题的上、下限定理给出了严密的证明,并建立了求解极限平衡问题的广义极限平衡法,均质土的计算结果表明,圆弧滑动面的广义极限平衡法与对数螺旋面的上限解法基本一致。 相似文献
19.
Łukasz Gągała 《International Journal of Earth Sciences》2009,98(2):461-479
In the course of numerical experiments selected algorithms for stress tensor inversion and separation of heterogeneous populations
of calcite twins and striated faults were tested. Artificial data sets were created in a manner simulating natural processes.
They were composed of data, dynamically compatible with one or two stress tensors and chaotic “noise” imitating natural imperfections.
For calcite twins the classical inversion procedure is considered valid, with restrictions regarding a high proportion of
chaotic data, when shape ratio of the stress tensor Φ is poorly constrained. The algorithm of Etchecopar (1984 fide Tourneret and Laurent in Tectonophysics 180:287–302, 1990) devised originally for calcite twins has been modified and applied to fault/slip data, facilitating a rejection of incompatible
outliers. Two main classes of data separation procedures were tested: separation contemporary with inversion and separation
prior to inversion, utilising hierarchical clustering. The separation contemporary with inversion performs moderately but
often fails with complex calcite twin sets. The performance of hierarchical clustering is high, but only with a σ
1 orientation as a similarity criterion—the new strategy introduced in this contribution. For fault/slip data the hierarchical
clustering with the right-dihedra construction as the similarity criterion (Nemcok et al. 1999) is satisfactory. Additionally, a new approach is proposed for fault/slip data, utilising principles of the classical algorithm
for heterogeneous populations of calcite twins. Validated algorithms for striated faults were successfully applied to a natural
data set from the Holy Cross Mts (central Poland). 相似文献
20.
An interface constitutive model is presented accounting for slip and sliding effects and also for dilatancy phenomena. The microslip effects are described by considering spherical asperity interaction with variation of contact area and generation of progressive or reverse slip zones. The incremental constitutive equations are derived with proper memory rules accounting for generation and annihilation of particular slip zones during the process of variable loading. It is further assumed that sliding of spherical contacts occurs along large asperities whose slope varies due to the wear process. The predicted shear and dilatancy curves are shown to provide close quantitative simulation of available experimental data. The strain ratchetting effect for non-symmetric cyclic loading was exhibited using the asperity wear model. The model presented could be applied to simulate rock joints, masonry, or concrete cracked interfaces, under monotonic and cyclic loading. 相似文献