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411.
在总结前人研究成果的基础上,全面系统地分析了诱发招远市金矿区崩塌的自然和人为因数,然后运用遥感技术对金矿区遥感图像进行处理,提取诱发崩塌的条件因子,聘请有经验的专家对各项诱发因子进行诊断分析,以此作为判断条件,在G IS技术的支持下对诱发崩塌的条件因子进行空间分析,预测出招远金矿区发生崩塌的危害程度,为防治崩塌提供科学依据。预测结果表明,招远金矿区崩塌有进一步发展的可能,其中,高危险区有36820 m2,中易发区有50 610 m2,低易发区有67 200 m2,需要采取有效措施加以防治。 相似文献
412.
20世纪90年代以来中外区域规划研究的对比分析 总被引:1,自引:0,他引:1
区域规划是国家政府进行区域管理的重要手段和方式之一。为了落实科学发展观和对区域发展有效宏观调控,区域规划成为国家“十一五”规划的重要内容。本文对比分析了1990年代以来国外区域规划研究的主要进展、以及我国区域规划研究的特点与不足,以期为推动我国当前新一轮区域规划的理论研究和实践创新提供有益启示。 相似文献
413.
发展中山会展旅游的思考 总被引:2,自引:0,他引:2
会展旅游是当今世界旅游业发展的一个重要方向,是一个蕴涵巨大价值的旅游项目,是都市旅游不可或缺的一部分。中山会展旅游不仅有着良好的区位条件,而且具有持续发展的良好经济环境。但中山会展旅游的宜传、促销力度不够,专业人才匮乏,市场运作不完善,旅游辅助作用有限,同时,面临周边城市的激烈竞争。对此,应把会展旅游作为培育中山旅游的重要动力来认识,加强对会展旅游的宣传推广,提高认识;培养专业人才,建立会展旅游组织;强化特色,准确定位;广泛协作联合,使广州的会展旅游走上可持续发展轨道。 相似文献
414.
Rama Mohan Kurakalva Narasimha Murthy Nyasavajhala Phani Homeshwari Mamidi Venkata Anjaiah Kanukuntla 《中国地球化学学报》2006,25(B08):202-203
A simple and rapid procedure to extract organochlorine pesticides (OCPs) from sediments by means of microwave energy is proposed. Sediment samples were irradiated with microwaves in a closed vessel system while immersed in hexane-acetone (1 : 1, v/v). The sample extracts were cleaned up using solid phase extraction with Florisil as adsorbent. Pesticides were eluted with hexane-ethyl acetate (80 : 20, v/v) and determined by gas chromatographic separation with electron capture detection. Three oven programs were assayed with two different solvent mixtures in order to achieve adequate experimental conditions for the complete extraction of organochlorine pesticides from the matrix. Different variables such as the composition of extraction solvent, 相似文献
415.
Effect of polypropylene fibre and lime admixture on engineering properties of clayey soil 总被引:2,自引:0,他引:2
In order to reduce the brittleness of soil stabilized by lime only, a recent study of a newly proposed mixture of polypropylene fibre and lime for ground improvement is described and reported in the paper. To investigate and understand the influence of the mixture of polypropylene fibre and lime on the engineering properties of a clayey soil, nine groups of treated soil specimens were prepared and tested at three different percentages of fibre content (i.e. 0.05%, 0.15%, 0.25% by weight of the parent soil) and three different percentages of lime (i.e. 2%, 5%, 8% by weight of the parent soil). These treated specimens were subjected to unconfined compression, direct shear, swelling and shrinkage tests. Through scanning electron microscopy (SEM) analysis of the specimens after shearing, the improving mechanisms of polypropylene fibre and lime in the soil were discussed and the observed test results were explained. It was found that fibre content, lime content and curing duration had significant influence on the engineering properties of the fibre–lime treated soil. An increase in lime content resulted in an initial increase followed by a slight decrease in unconfined compressive strength, cohesion and angle of internal friction of the clayey soil. On the other hand, an increase in lime content led to a reduction of swelling and shrinkage potential. However, an increase in fibre content caused an increase in strength and shrinkage potential but brought on the reduction of swelling potential. An increase in curing duration improved the unconfined compressive strength and shear strength parameters of the stabilized soil significantly. Based on the SEM analysis, it was found that the presence of fibre contributed to physical interaction between fibre and soil whereas the use of lime produced chemical reaction between lime and soil and changed soil fabric significantly. 相似文献
416.
Performance of Mortar and Chemical Grout Injection into Surrounding Soil When Slurry Pipe-jacking Method is Used 总被引:1,自引:0,他引:1
Hideki Shimada Takashi Sasaoka Saeid Khazaei Yasuhiro Yoshida Kikuo Matsui 《Geotechnical and Geological Engineering》2006,24(1):57-77
Small-diameter shallow tunnels are often being built by using the slurry pipe-jacking method. This system involves the pushing
or thrusting of a drivage machine and concrete pipes into the ground. Chemical grout injection into the surrounding soil around
the tunnel is carried out after the drivage and pushing processes are finished. The purpose of the chemical grout injection
is to maintain permanent stability of the surrounding soil. However, the behavior of the chemical grouting material in the
surrounding soil around the tunnel and the amount of optimum injection is not clearly understood. From these points of view,
this paper discusses the performance of the chemical grouting material, when it is injected into the surrounding soil around
the tunnel, by means of 2-D Eulerian–Lagrangian seepage analysis. Moreover, the effectiveness of the chemical grout injection
was evaluated by using the non-linear finite element method. This investigation show when the range of the grouted zone is
designed; it is necessary that the relationship between Young’s modulus of the soil/grouted zone and the confining stress
be taken into consideration in order to establish effective, economical and safe chemical grout injection system. Understanding
the performance of the seepage/dispersion behavior of the chemical grout and the characteristics of soil/ grouted zone is
also important. 相似文献
417.
Structural changes during dehydration and subsequent decomposition in thaumasite Ca3Si(SO4)(CO3)(OH)6·12 H2O were studied by in situ synchrotron powder diffraction between 303 and 1,098 K. Evolution of the crystal structure was observed through 28 structure refinements, by full profile Rietveld analysis performed in the P63 space group, between 300 and 417 K, whereupon the thaumasite structure was observed to breakdown. Within this temperature range, the cell parameters of thaumasite increased as a function of temperature in a nearly linear fashion up to about 393 K, at which temperature, a slight slope change was observed. Above 400 K, the thermogravimetric analysis revealed that the dehydration process proceeded very rapidly while the refined occupancy of water molecules dropped below a critical level, leading to instability in the thaumasite structure. At a same time, a remarkable change in the unit cell parameters occurring at about 417 K indicated that the crystal structure of thaumasite collapsed on losing the crystallization water and it turned amorphous. This result indicated that the dehydration/decomposition of thaumasite was induced by the departure of the crystallization water. At about 950 K, anhydrite and cristobalite crystallized from the thaumasite glass. 相似文献
418.
A Practical Procedure for the Measurement of Fragmentation by Blasting by Image Analysis 总被引:1,自引:0,他引:1
Summary. The operation of a digital image analysis system in a limestone quarry is described. The calibration of the system, required
in order to obtain moderately reliable fragmentation values, is done from muckpile sieving data by tuning the image analysis
software settings so that the fragmentation curve obtained matches as close as possible the sieving. The sieving data have
also been used to extend the fragment size distribution curves measured to sizes below the system’s optical resolution and
to process the results in terms of fragmented rock, discounting the material coming from a loose overburden (natural fines)
that is cast together with the fragmented rock. Automatic and manual operation modes of the image analysis are compared. The
total fragmentation of a blast is obtained from the analysis of twenty photographs; a criterion for the elimination of outlier
photographs has been adopted using a robust statistic. The limitations of the measurement system due to sampling, image processing
and fines corrections are discussed and the errors estimated whenever possible. An analysis of consistency of the results
based on the known amount of natural fines is made. Blasts with large differences in the amount of fines require a differentiated
treatment, as the fine sizes tend to be the more underestimated in the image analysis as they become more abundant; this has
been accomplished by means of a variable fines adjustment factor. Despite of the unavoidable errors and the large dispersion
always associated with large-scale rock blasting data, the system is sensitive to relative changes in fragmentation. 相似文献
419.
Substantial damage to water supply systems, including water delivery pipelines, water treatment plants, reservoirs, and water
storage tanks, was reported after the 1999 Chi–Chi Taiwan Earthquake. This paper first summarizes the damage survey and then
presents the results of seismic fragility analysis for underground pipelines. Construction blueprints of the water delivery
pipelines and repair work orders of 11 townships and cities in the disastrous area were digitized into a Geographical Information
System (GIS) for analysis and assessment. With the aid of the GIS system, we found that PVC pipes made up 86% of water delivery
pipelines while steel, cast iron, ductile iron, PE and others took the rest. Therefore, this paper focuses on the fragility
analysis of PVC pipes. Three different methods were applied to derive the fragility relations between the PVC water pipes
having nominal diameters (approximately inner diameters) greater than or equal to 65 mm and earthquake intensity parameters
such as peak ground acceleration and peak ground velocity. The results were then examined with those of other countries. The
discrepancy between our results and the empirical equation used by HAZUS, an earthquake loss estimation software developed
by the Federal Emergency Management Agency was not significant. 相似文献
420.
V. A. Marinov S. V. Meledina O. S. Dzyuba O. S. Urman O. V. Yazikova V. A. Luchinina A. G. Zamirailova A. N. Fomin 《Stratigraphy and Geological Correlation》2006,14(4):418-432
Paleontological study of Upper Jurassic and Lower Cretaceous sediments recovered by boreholes in the Agan-Vakh and Nadym-Vengapur interfluves clarified environments of their deposition. As is shown, influx of siliciclastic material to central areas of the West Siberian sea basin varied through time. Taxonomic composition and ecological structure of nektonic and benthic fossil assemblages are analyzed and considered in terms of environmental factors such as hydrodynamics, aeration, temperature, and salinity of seawater. 相似文献