影响钻孔灌注桩质量若干因素分析及其控制措施     

张益飞 《江苏地质》2003,27(2):110-112

分析了影响钻孔灌注桩成桩质量的若干因素，如桩孔垂直度、孔深、孔径、沉渣、砼的拌制和砼灌注工艺及现场施工管理等。提出了相应质量保证的控制措施。  相似文献   

S和S-L型构造岩的显微组构与渗透性能的声学识别   总被引：1，自引：0，他引：1  

刘德良  李振生孙岩杨树锋  陶士振 《岩石学报》2007,23(4):849-854

为了解断裂与流体渗透的动态关系,针对S和S-L型构造岩及其原岩,采用超声波实验方法测算岩石的波速和衰减,经过与孔隙度等微孔隙结构参数的对比和相关分析,研究认为:S-构造岩和(S-L)-构造岩具有明显的各向异性,在平行面理方向上,波速和品质因子较大,渗透性最强,是最佳的流体运移方向;在垂直面理方向上,波速和品质因子较小且通常小于原岩的,封闭性最强,是最佳的封闭流体方向。波速和品质因子分别与孔隙度具有负线性关系,与气柱高度、突破压力等表征岩石封闭性能的参数具有正相关关系。张性角砾岩的波速和品质因子小于原岩的,而渗透性增强,并无明显的各向异性。  相似文献   

Seismic attenuation of coda waves in the eastern region of Cuba   总被引：1，自引：0，他引：1  

Berta Biescas  Zulima Rivera  Jose Alejandro Zapata 《Tectonophysics》2007,429(1-2):99-109

Cuba's seismic attenuation had never been studied in detail. In this paper we present the results of the research on the seismic attenuation of Cuba's eastern zone based upon the information collected by the seismological Cuban network from 1998 to 2003. 581 earthquakes were selected from the Cuban catalogue to make this study. All of them, recorded by at least three seismic stations, had their epicenters located in the eastern Cuban region (19.3–22 N, 79–73 W), epicentral distances between 15 km and 213 km, their coda duration magnitudes ranging from 2 and 4.1 and their focal depths reaching up to 30 km. The seismic wave attenuation was studied using coda waves. The single scattering method proposed by Sato in 1977 was applied, the attenuation and frequency dependency for different paths and the correlation of the results with the geotectonics of the region are presented in this paper.The mean Q_c value calculated was Q_c = (64 ± 2)f^{0.84 ± 0.01}. The relatively low Q₀ and the high frequency dependency agree with the values of a region characterized by a high tectonic activity. The Q_c values of seven subregions of eastern Cuba were calculated and correlated with the geology and tectonics of the area.  相似文献   

谈GIS的数据质量   总被引：1，自引：0，他引：1  

赵晓红  王西光 《测绘与空间地理信息》2007,30(6):114-116

作为全球信息化浪潮重要组成部分的地理信息系统(GIS)的建设与应用,得到了科技界、企业界和政府部门的广泛关注,其中GIS的数据质量是一个关系到GIS数据可靠性和GIS系统可信度的重要问题,与系统成败密切相关。本文阐述了GIS数据质量的基本理论及检测方法。  相似文献   

RTK技术在公路工程中的应用探讨     

史跃辉  陈文迅 《现代测绘》2007,30(5):23-25

本文拟采用理论与实践相结合、定性与定量分析相结合、规范分析与实证分析相结合的方法，运用GPS原理及误差分析理论，结合实例和GPS技术的优点，快捷实时地为公路测量提供基础数据，进而为公路测量提供方便、实用的技术指导。  相似文献   

Eddy covariance measurements of carbon dioxide,latent and sensible energy fluxes above a meadow on a mountain slope     

Albin Hammerle  Alois Haslwanter  Michael Schmitt  Michael Bahn  Ulrike Tappeiner  Alexander Cernusca  Georg Wohlfahrt 《Boundary-Layer Meteorology》2007,122(2):397-416

Carbon dioxide, latent and sensible heat fluxes were measured by means of the eddy covariance method above a mountain meadow situated on a steep slope in the Stubai Valley in Austria, based on the hypothesis that, due to the low canopy height, measurements can be made in the shallow equilibrium layer where the wind field exhibits characteristics akin to level terrain. In order to test the validity of this hypothesis and to identify effects of complex terrain in the turbulence measurements, data were subjected to a rigorous testing procedure using a series of quality control measures established for surface-layer flows. The resulting high quality dataset comprised 36% of the original observations, the substantial reduction being mainly due to a change in surface roughness and associated fetch limitations in the wind sector dominating during nighttime and transition periods. The validity of the high quality dataset was further assessed by two independent tests: (i) a comparison with the net ecosystem carbon dioxide exchange measured by means of ecosystem chambers, and (ii) the ability of the eddy covariance measurements to close the energy balance. The net ecosystem CO₂ exchange measured by the eddy covariance method agreed reasonably well with ecosystem chamber measurements. The assessment of the energy balance closure showed that there was no significant difference in the correspondence between the meadow on the slope and another one situated on flat ground at the bottom of the Stubai Valley, available energy being underestimated by 28% and 29%, respectively. We thus conclude that, appropriate quality control provided, the eddy covariance measurements made above a mountain meadow on a steep slope are of similar quality as compared to flat terrain.  相似文献   

Communicating human health risks associated with disinfection by-products in drinking water supplies: a fuzzy-based approach   总被引：1，自引：2，他引：1  

Rehan Sadiq  Manuel J. Rodriguez  Syed A. Imran  Homayoun Najjaran 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(4):341-353

Chlorine used for the disinfection of water supplies can react with naturally occurring organic compounds and form potentially harmful disinfection by-products (DBPs). A risk index for two regulated groups of chlorinated DBPs—trihalomethanes (THMs) and haloacetic acids (HAAs), using fuzzy C-means (FCM) clustering algorithm and fuzzy rule-based modeling is proposed for risk communication. The proposed index evaluates the cancer and non-cancer risks individually for THMs and HAAs using the FCM algorithm. Subsequently, two different fuzzy rule-bases were used to evaluate the overall risk-index based on cancer and non-cancer risks. The overall risk-index will provide drinking water utilities with an effective communication tool for communicating aggregated water quality compliance. Simulated DBP occurrence data obtained from the City of Quebec, Canada, is used to demonstrate the application of this methodology.  相似文献   

ESTIMATION OF ERRORS IN ABSORBANCE RATIO MEASUREMENTS     

MUHAMMAD SHARAF GARY ARROY RON PERKINS Spectra-Physics Inc.  North First Street  San Jose  CA  U.S.A. 《地理学报(英文版)》1991,(3)

Ratio measurements are commonly used to address a variety of analytical problems in environmental,forensic and pharmaceutical laboratories.In absorbance ratioing techniques,analytical chemists rely onthe spectral features of the analyte(s)of interest.The absorbances at two wavelengths are monitored andthe ratio of these two absorbances is computed.This ratio is then used to confirm the identity of theanalyte(s)of interest,the purity of a product or the overlap of chromatographic peaks.These decisionsoften have far-reaching consequences(e.g.the identification of the source,biogenic or petrogenic,ofhydrocarbons in biological tissues or water).Given the cost and the liabilities associated with suchdecisions,it is unfortunate that these ratios are seldom reported with any statistical confidence.Thepurpose of this study is to delineate the parameters that affect absorbance ratio measurements.Themodels that can be used to estimate the statistical confidence in these measurements are derived andevaluated experimentally.The results show that these models can estimate the relative standard deviationsin absorbance ratios accurately.They can also estimate the effect of signal-to-noise ratio and the choiceof wavelengths on the precision of absorbance ratios.  相似文献   

数字测绘产品的质量检查与质量控制   总被引：6，自引：0，他引：6  

王冬滨  王铁军 《测绘工程》2000,9(1):47-51

介绍了最新的数字化测绘生产技术和数字测绘产品的种类及用途,讨论了有关数字测绘产品质量检查和质量控制的一些问题。  相似文献   

A groundwater survey of the greater Durban area and environs, Natal, South Africa   总被引：1，自引：0，他引：1  

F. G. Bell  R. R. Maud 《Environmental Geology》2000,39(8):925-936

Received: 15 June 1999 · Accepted: 30 August 1999  相似文献