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991.
针对不同等级测量控制网的联合平差,介绍一种不使用导数的解析方法,该方法一方面克服了传统平差中由于起算数据误差对低级网的精度影响,而使加密的精度逐次降低的缺点;另一方面,完全避免了导数的计算,大大减少了计算工作量。 相似文献
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3G技术与现代物流管理技术的集成模式研究 总被引:3,自引:1,他引:3
3G技术能够对现代物流作业与管理进行有效地监督和控制,3G技术与现代物流管理技术的集成是物流业发展的客观需要。探讨了3G技术与现代物流管理技术的集成模式,对于以GIS技术为平台支撑、以定位技术和无线通信技术为辅助手段的分布式空间物流信息系统的建设具有一定的意义。 相似文献
996.
本文系统研究了小浪底工程的岩体的强度特征,采用了室内试验,野外结构面统计,工程地质类比法、模型试验法和Hoek Brown的经验法,估算了工程岩体的力学指标,指出了上述各种方法中所存在的不足,认为在工程实践中,应尽可能使用多种估计方法,交叉校核所得参数,以提高参数的可靠性,保证工程的安全,节约投资。 相似文献
997.
为了客观地反映各因素对目标问题的影响程度,本文首次提出了最佳因素权重概念。定义最佳因素权重为研究区域内系统质量处于极限状态时的各因素权重之组合。结合深港西部通道工程深圳湾公路大桥桥址比选方案,详细说明了本方法的研究思路及其确定方法。通过最佳因素权重方法,能客观地、定量地确定出多因素复杂系统中的最优场址。 相似文献
998.
W. Lu W. Hustrulid 《Fragblast: International Journal for Blasting and Fragmentation》2003,7(4):231-255
Airdecking is used in mining for two quite different applications. One is to enhance the fragmentation by amplifying the induced fracturing and the second is for pre-split blasting in which the borehole fracturing is reduced. This paper deals with the first of these effects. A forth coming paper will describe pre-splitting by airdecking. The use of air decks to enhance rock fragmentation and so to reduce explosive costs has been the practice for quite long time. Although a number of studies has been conducted to verify the advantages of blasting with air decks and to investigate the mechanisms involved, the proposed mechanisms still cannot explain clearly the phenomena observed in practice and the design approach adopted for this kind of blasting is still primary based on rules-of-thumb. In this paper, the theory of shock tubes is adopted to (a) investigate the processes of the expanding detonation products, (b) study the interactions between the explosion products and the stemming or bottom of blasthole, and (c) to decide the distribution of the changing pressure of explosion products along blasthole. Numerical simulation and theoretical analyses are then performed to study the physical process of blasting with air decks. Finally, a reasonable value for the airdecking ratio is decided theoretically. It is shown that the pressure-unloading process caused by the propagation of the rarefaction wave and the reflected rarefaction waves in the detonation products plays an important role in the enhanced fragmentation of rock when blasting with air decks. The unloading process can induce tensile stresses of rather high magnitude in the rock mass surrounding blasthole. This favors fracturing of the rock. The reflected shock wave with a magnitude of gas pressure higher than that of the average detonation pressure in a fully charged blasthole acts as the main energy source to break the rock in the air deck and stemming portions. The second and succeeding strain waves induced by the unloading or reloading of the pressurewithin the blasthole also contribute to form the initial fracture network in the rock around the blasthole. It is also revealed that there exists a reasonable range of values for the airdecking ratio. For ANFO, this value varies from 0.13-0.40. 相似文献
999.
Horie Kei Maki Norio Kohiyama Masayuki Lu Hengjian Tanaka Satoshi Hashitera Shin Shigekawa Kishie Hayashi Haruo 《Natural Hazards》2003,29(3):341-370
Rebuilding of victims' livelihoods was a crucial issue in the restoration process in the1995 Hanshin-Awaji Earthquake Disaster. Housing damage assessment influencedmost of the rebuilding of the livelihood in the long term, because the Victim Certificatesissued by the local governments based on the results of the Housing damage assessmentwas required to receive most of the individual assistance measures. In the process ofHousing damage assessment, many complex problems arose, leading to extensivework on the part of the disaster responders. Consequently, a considerable number ofvictims were dissatisfied with the assessment and applied for a resurvey. Due to a floodof requests for resurvey, disaster responders had to work on damage assessment, leavingrelief activities aside.In order to facilitate Housing damage assessment, this paper discusses thefollowing five points: (1) the processes and the problems of assessments performedin the Hanshin-Awaji Earthquake Disaster, (2) the changes in the nature of informationneeded by the victims, (3) the improvements over the present damage assessment, (4)the housing situation in Japan, and (5) the international situation on damage assessment.It is obvious from the results that a poor damage assessment system and the size ofthe disaster produced a very large work load. Differences in appreciation among theinvestigators also contributed to unfair assessments and led to the victims beingincreasingly dissatisfied by the survey results. Finally, a design concept for acomprehensive damage assessment system, which has been derived from theabove five points, is proposed for post-disaster management. 相似文献
1000.