A three dimensional model of muckpile formation and grade boundary movement in open pit blasting     

R. L. Yang  A. Kavetsky 《Geotechnical and Geological Engineering》1990,8(1):13-34

Summary Formulation and case studies of a three dimensional kinematic model are presented. Thein situ overburden geometry can be simulated accurately and various initiation patterns of blasts can be modelled. The overburden geometry, hole patterns and explosive distribution are all explicit model inputs. Because the effect of explosive properties, rock mass condition and inter-row delay are very difficult to measure in terms of blast performance, these are represented in the model by control parameters which are left for calibration using field data. The output of the model is a three dimensional muckpile shape of any cross section and a contour map of grade distribution within the muckpile. Two case studies are presented which have shown that the model is a valuable tool for optimizing production blasting as well as for controlling grade dilution during blasting.  相似文献   

高精度锥体棱镜的“自差法”检测技术   总被引：2，自引：0，他引：2  

殷达安  林银森 《测绘学报》1994,23(3):216-221

本文提出一种采用“自差法”检测高精度锥体棱镜的新方法，阐述检测原理与装置，建立检测角度和面形误差的定量判据，并给出一个实例说明其应用。实践表明，“自差法”检测技术对于产品质量的控制，具有快速准确和简便实用等特点。  相似文献   

Tunnel blasting techniques in difficult ground conditions   总被引：1，自引：0，他引：1  

A. K. Chakraborty  J. L. Jethwa 《Geotechnical and Geological Engineering》1994,12(4):219-239

Summary The quality of tunnelling can be improved by proper blast design which takes into account the rock mass conditions. The effects of different rock mass properties on tunnel blast performance need to be assessed. The strength of the formation and joint orientation critically affected fragmentation and overbreak in a model study of blasting. Similar effects were noted in situ when the performance of a blast pattern in different rock mass conditions in the Tandsi inclines (Bihar, India) were analysed. Accordingly, the on-going blast pattern was modified for the poor ground conditions prevailing in the rest of the inclines. Improved fragmentation and smooth profile were obtained as a result; the rate of drivage improved considerably and the cost of excavation was reduced. Based on the observations in the model studies and the investigations at Tandsi, some guidelines for optimum blast design in difficult ground conditions are suggested.  相似文献   

转矩转速传感器及其在钻机功率测试中的应用   总被引：1，自引：0，他引：1       下载免费PDF全文

彭忍社 《探矿工程》1994,(1):51-52,54

介绍了一种用于钻机功率测试的转矩转速传感器，论述了该类传感器的基本工作原理、标定装置、校验方法以及测试系统的组成等问题。  相似文献   

An analysis of coal bump liability in a bump prone mine     

A. Wahab Khair 《Geotechnical and Geological Engineering》1985,3(4):243-259

Summary This paper presents an analysis of causes of bump in a deep coal mine. The analysis consists of in-mine measurement determination, analysis of physical and mechanical properties of mine materials and simulation of mine layout and mining sequence. Major factors contributing to the causes of bump have been reviewed and those that are related to this case have been identified and simulated analytically using a three-dimensional finite element method.  相似文献   

Complex behaviour of a coal sample in a large scalein situ compression test     

Tadeusz Cyrul 《Geotechnical and Geological Engineering》1986,4(4):257-271

Summary A large scalein situ compression test of a laminated coal cube is described. The cube was uniformly loaded by a system of hydraulic jacks supplied simultaneously from one pump. At the same time both load and deformations were controlled. Deformations were measured by 60 longitudinal gauges located at the side surface of the cube in the regular net. Due to the heterogeneity of the rock the readings showed scatter. As a first approximation, the scattered data were fitted to the plane using the least square method. Orientations of the planes were analysed and show permanent relative movement between adjacent lamina indicating complex behaviour of the cube under loading. Detailed analysis of this behaviour indicated that the cube was subjected to both bending and twisting.  相似文献   

Suction-controlled triaxial testing: Laboratory procedures in relation to resistance envelope methods     

M. G. Anderson  M. J. Kemp 《地球表面变化过程与地形》1987,12(6):649-654

In certain tropical slopes it appears possible that soil suction may play a significant role in maintaining stability. This communication outlines a laboratory suction-controlled triaxial test that can be undertaken to validate the threshold suction predicted by resistance envelope methods. It is shown that for two sites examined in St. Lucia, West Indies, the results from such a test confirm results obtained by use of resistance envelopes.  相似文献   

Hypotheses for earthquake occurrences     

Naveen  P. S. Moharir  V. K. Gaur 《Journal of Earth System Science》1983,92(3):261-281

Very little work has been done in generating alternatives to the Poisson process model. The work reported here deals with alternatives to the Poisson process model for the earthquakes and checks them using empirical data and the statistical hypothesis testing apparatus. The strategy used here for generating hypotheses is to compound the Poisson process. The parameter of the Poisson process is replaced by a random variable having prescribed density function. The density functions used are gamma, chi and extended (gamma/chi). The original distribution is then averaged out with respect to these density functions. For the compound Poisson processes the waiting time distributions for the future events are derived. As the parameters for the various statistical models for earthquake occurrences are not known, the problem is basically of composite hypothesis testing. One way of designing a test is to estimate these parameters and use them as true values. Momentmatching is used here to estimate the parameters. The results of hypothesis testing using data from Hindukush and North East India are presented.  相似文献   

Modern Numerical Ephemerides of Planets and the Importance of Ranging Observations for Their Creation     

E.V. Pitjeva 《Celestial Mechanics and Dynamical Astronomy》2001,80(3-4):249-271

The JPL planetary and lunar ephemerides – DE200/LE200, DE403/LE403, DE405/LE405 and the planetary and lunar ephemerides, EPM87, EPM98, and EPM2000, constructed in the Institute of Applied Astronomy of RAS are described. Common properties and differences of the various ephemerides are given. Graphical comparisons of the DE ephemerides with each other and with the EPM ephemerides are presented. A fairly good agreement of planetary orbits is between DE403, DE405 and EPM98, EPM2000, respectively, over the interval of 120 years (1886–2006) covered by EPM98 and EPM2000. Some differences are explained by a slight disagreement in representing the orbits of Ceres, Pallas, and Vesta as they affect the planets. The accurate radar observations of planets and spacecraft make it possible not only to improve the orbital elements of planets but to determine a broad set of astronomical constants as well: km/AU, parameters of Mars rotation including its precessional rate, the masses of Jupiter, Ceres, Pallas, and Vesta, relativistic parameters of the PPN formalism, the variability of the gravitational constant G. These have been obtained in the fitting process of the DE405 and EPM2000 ephemerides to observational data, including nearly 80000 American and Russian radar observations of planets (1961–1997), ranging and doppler to the Viking and Pathfinder landers, and other miscellaneous measurements from various sources and spacecraft.  相似文献   

大跨预应力混凝土空间框架结构的地震振动台试验研究     

熊学玉  耿耀明  李春祥  黄鼎业 《地震工程与工程振动》2005,25(1):102-107

利用地震振动台对大跨预应力混凝土井式梁空间框架结构的抗震性能进行了实验研究。两个模型的实验结果表明：(1)大跨预应力井式梁空间框架结构可以提供大的楼层平面内刚度；(2)对称大跨预应力井式梁空间框架结构，可以不考虑耦合地震反应；(3)大跨预应力井式梁空间框架结构的竖向地震反应中心大而周边小；(4)在相同加速度但不同的地震波作用下，结构的竖向地震反应不同。  相似文献