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851.
通过江苏省苏州工业园区等地基加固工程的施工,介绍了劈裂注浆的施工工艺、加固机理、设备机具、过程控制以及施工问题与对策。 相似文献
852.
Tectonic evolution of the Dabieshan orogen: In the view from polyphase deformation of the Beihuaiyang metamorphic zone 总被引:1,自引:0,他引:1
LIN Wei Faure Michel WANG Qingchen & Arnaud Nicolas . LTE Institute of Geology Geophysics Chinese Academy of Sciences Beijing China . Department of Earth Planetary Sciences Graduate School of Science Nagoya University Japan . ISTO UMR CNRS Batiment Géosciences Orléans Université d’Orléans Orléans Cedex France . UMR "Magmas et Volcans" Rue Kessler Clermont-Ferrand France 《中国科学D辑(英文版)》2005,48(7)
The Dabieshan and its geological counterpart in the Sulu area represent the eastern part of the Qinling-Dabie orogenic belt in Eastern China. This Orogen corresponds to the collision zone between the North and South China blocks (denoted as NCB and SCB, respectively) during the Early Mesozoic. Since the discovery of ultra-high-pressure (UHP) metamor- phism[1?3], research of the Dabieshan has made great progress from petrological work (e.g. Cong and Wang, 1999 and enclosed references)[… 相似文献
853.
A field study to examine the statistical character of dune morphology and the correlation among dune morphology, discharge, and flow resistance was conducted in a meandering reach of Lillooet River, near Pemberton, British Columbia, Canada. The field season spanned the 1995/1996 hydrologic year with sample day discharge events ranging between 33 and 425 m3 s−1. Surveys of the bed morphology along the thalweg in two dune fields (A and B) were completed using an echo sounder with chart recorder that enabled the measurement of more than 4000 dunes. Dune height ranged between 0.08 and 0.96 m, length between 2.01 and 20.99 m, and steepness between 0.02 and 0.10. Histograms of each dune shape (height, length, steepness) sample most often displayed positive skewness and non-Gaussian distributions (Gamma, Beta, and Weibull); median sample height and length histograms displayed positive skewness; and steepness was nearly Gaussian. Histograms of all dimensionless dunes (i.e., measurement divided by average measurement of sample) were Gaussian and slightly leptokurtic. Neither the height nor length of dunes measured in this investigation were successfully predicted by the empirical models of Allen [Allen, J.R.L., 1984. Developments in Sedimentology. Sedimentary Structures: Their Character and Physical Basis, 2nd edn. Elsevier, New York, vol. 30 (A and B), 1256 pp.], Fredsøe [J. Hydraul. Div., Am. Soc. Civ. Eng. 108(HY8) (1982) 932.], or Yalin [J. Hydraul. Div., Am. Soc. Civ. Eng. 90(HY5) (1964) 105.]. Least-squares regression models for dune–height relations produced here are similar to models published by other field researchers; regression models for dune length only conform to those developed elsewhere if the discharge of the study rivers was similar. The energy gradient in dune field A varied within a smaller range than in field B, enabling dune size to become more fully equilibrated with respect to flow environment. Although the average Froude numbers were much less than critical, dunes appeared to wash out towards a plane bed as discharge increased due to a change from a bedload to suspended-load dominated sediment-transport regime. Flow resistance increased most rapidly during changes in base flow and at the beginning and end of the seasonal flood; resistance tended to be smaller in field A than B, reflecting local differences in energy gradient. Flow resistance increased until a dune steepness of 0.070 was attained and then decreased. The steepness value was considered to be coincident with kolk generation [Dyer, K.R., 1986. Coastal and Estuarine Sediment Dynamics. Wiley, NY, 342 pp.], suggesting that macroturbulent flow structures play an important role in defining the roughness of dunes on a channel bed. 相似文献
854.
以辽宁地震前兆数据的传输与处理流程为基础,针对流程中多个传输处理环节的不同前兆报文,加以规范和分析。同时应用计算机技术和语言,实现对前兆数据的多层次纠错检查,并对此系统软件的研制背景、思路、功能特色及应用情况做了介绍。 相似文献
855.
Philippe Philippe Alain M. Dabas Christian Haeberli Pierre H. Flamant 《Boundary-Layer Meteorology》2003,106(3):483-505
The flow structure at the intersection between the Rhine and the Seez valleys nearthe Swiss city of Bad Ragaz has been documented by means of wind and pressuremeasurements collected from 9 September to 10 November 1999 during the MesoscaleAlpine Programme (MAP) experiment. To understand better the dynamics of theageostrophic winds that develop in this part of the Rhine valley, some key questionsare answered in this paper including the following: (i) How does air blow at theintersection of the Rhine and Seez valleys? and (ii) what are the dynamical processes(mechanical or thermal) driving the flow circulations in the valleys? Statistical analysis of the wind and pressure patterns at synoptic scale and at the scaleof the valley shows that five main flow patterns, SE/S, NW/W, NW/N, NW/S, SE/N(wind direction in the Seez valley/wind direction in the Rhine valley) prevail. The SE/S regime is the flow splitting situation. It is mainly driven by a strong pressure gradient across the Alps leading to foehn, even though some nocturnal cases are generated bylocal thermal gradients. The NW/W and NW/N regimes are mechanically forced bythe synoptic pressure gradient (as the flow splitting case). The difference between thetwo regimes is due to the synoptic flow direction [westerly (northerly) synoptic flowfor the NW/W (NW/N) regime], showing that the Rhine valley (particularly from BadRagaz to Lake Constance) is less efficient in channelling the flow than the Seez valley.The NW/S (occurring mainly during nighttime) and SE/N (occurring mainly duringdaytime) regimes are mainly katabatic flows. However, the SE/N regime is also partlyforced at the synoptic scale during the foehn case that occurred between 18 October and 20 October 1999, with a complex layered vertical structure. This analysis also shows that, contrary to what was observed in a broad section of theupper Rhine valley near Mannheim, very few countercurrents were observed near BadRagaz where the valley width is much smaller. 相似文献
856.
857.
根据详实的野外资料对新疆阜康 -吉木萨尔断裂带的构造几何特征和活动性进行了分析与研究 ,结果表明 :断裂带由东、西两大段组成 ,西段由 4条次级S倾逆断裂左行斜列组成 ,东段由 3条次级S倾逆断裂右行斜列组成 ,总体上呈向北微凸的近EW向展布 ,长达 14 0km ,控制着东天山北缘的第四纪构造演化和地貌发育 ;组成断裂往往是低角度的逆断层 ,与褶皱共生 ,切割深度 5~ 6km ,第四纪晚期多期 (次 )活动 ,以间歇性稳定滑动为特征 ;断裂带端部段落倾角较大 ,活动量较小 ,全新世平均垂直滑动速率为 0 .10~ 0 4 0mm/a ,中部段落以低倾角的推覆为特征 ,活动强烈 ,全新世平均垂直滑动速率达 0 80~ 1 0 0mm/a以上 相似文献
858.
FLOW PATTERNS AND DAMAGE OF DIKE OVERTOPPING 总被引:1,自引:0,他引:1
Damage of a dike may result in severe damage and suffering. To reduce downstream damage and loss of life, it is important to study the process of breaching of the damaged dike. It is not possible to understand the damage process without a clear understanding of the flow patterns encountered. In the present study, data obtained from nine experimental runs are analyzed. The flow patterns and progressive damage of dike overtopping are investigated. Two types of phenomena at the dike surface: erosion; and erosion and sliding, are observed during the overtopping event. Four stages of dike damage can be distinguished. The degradation rate of the dike crest is found to be dependent on the downstream slope of the dike. The degradation rate is higher when the downstream slope is steeper. 相似文献
859.
Salvatore AlparoneSalvatore Gambino 《Physics of the Earth and Planetary Interiors》2003,135(4):281-289
On 9 January 2001, a seismic swarm, located on the south-eastern flank of Mt. Etna and with nearly identical waveforms, caused some damage to Zafferana Etnea village, 3 km from the epicentral area.An analysis of the seismicity occurring in the last 8 years in this area has revealed other earthquakes with the same characteristics; some pre-empted and followed (up to a few months) the 2001 January swarm, others were recorded more than five years beforehand.Using similarity of waveforms, these earthquakes were classified into three families.The use of a multiplet-technique has allowed to obtain the spatial distribution of the events with higher precision (mean error of 10-20 m) with respect to traditional localization techniques.Mt. Etna earthquakes relocation clearly describes the geometry of the seismogenic tectonic structure; the hypocenters lie on a NE-SW oriented plane that is coincident with one of the focal planes obtained by first-arrival polarities. This alignment is also coherent with one of the main regional tectonic trends cutting the Mt. Etna area, and can be interpreted as a right-lateral strike seismic source on the south-eastern flank of Mt. Etna, distant from eruptive centres, which repeats from time to time and is able to produce strong energy releases. 相似文献
860.
The Sudbury Structure, formed by meteorite impact at 1850 Ma, consists of three major components: (1) the Sudbury Basin; (2) the Sudbury Igneous Complex, which surrounds the basin as an elliptical collar; and (3) breccia bodies in the footwall known as Sudbury Breccia. In general, the breccia consists of subrounded fragments set in a dark, fine-grained to aphanitic matrix. A comparison of the chemical composition of host rocks, clasts and matrices indicates that brecciation was essentially an in-situ process. Sudbury Breccia forms irregular-shaped bodies or dikes that range in size from mm to km scale. Contacts with the host rocks are commonly sharp. The aspect ratio of most clasts is approximately 2 with the long axes parallel to dike walls. The fractal dimension (Dr)=1.55. Although there appears to be some concentration of brecciation within concentric zones, small Sudbury Breccia bodies within and outside these zones have more or less random strikes and steep dips. Sudbury Breccia bodies near an embayment structure tend to be subparallel to the base of the Sudbury Igneous Complex. Sudbury Breccia occurs as much as 80 km from the outer margin of the Sudbury Igneous Complex. In an inner zone, 5 to 15 km wide, breccia comprises 5% of exposed bedrock with an increase in brecciation intensity in embayment structures. Sudbury Breccia may be classified into three types based on the nature of the matrix: clastic, pseudotachylite and microcrystalline. Clastic Sudbury Breccia, the dominant type in the Southern Province, is characterized by flow-surface structures. Possibly, a sudden rise in pore pressure caused explosive dilation and fragmentation, followed by fluidization and flowage into extension fractures. Pseudotachylite Sudbury Breccia, mainly confined to Archean rocks, apparently formed by comminution and frictional melting. Microcrystalline Sudbury Breccia formed as a result of the thermal metamorphism, of the North Range footwall, by the Sudbury Igneous Complex. This produced a zone, approximately 1.2 km wide, wherein the matrix of the breccia either recrystallized or, locally, melted. An overprint of regional metamorphism obliterated contact effects in the South Range footwall. The Ni–Cu–PGE magmatic sulphide deposits may be classified into four types based on structural setting: Sudbury Igneous Complex–footwall contact, footwall, offset, and sheared deposits. Sudbury Breccia is the main host for footwall deposits (e.g., McCreedy East, Victor, Lindsley). Sudbury Breccia locally hosts mineralization in radial (e.g., Parkin and Copper Cliff) and concentric (e.g., Frood–Stobie) offset dikes. 相似文献