层状地基持力层承载力的确定   总被引：1，自引：0，他引：1  

李连营  林波 《岩土工程技术》2004,18(5):235-237

通过对层状地基的分析 ,提出了对层状地基持力层承载力进行修正的方法 ,并通过对同一住宅小区已沉降稳定的 2栋楼采用的承载力及使用情况分析 ,验正本方法的合理性  相似文献   

长短桩复合地基设计计算的探讨   总被引：9，自引：3，他引：9  

孙艳林 《岩土工程技术》2004,18(5):252-254

通过对长短桩复合地基承载力计算的不同公式进行对比分析 ,提出比较适宜的设计方法 ,并提出其沉降计算公式和加固效果检测方式 ,并将长短桩复合地基理论灵活应用于补桩设计  相似文献   

洮儿河扇形地修建地下水库可行性研究   总被引：7，自引：3，他引：7  

肖长来  兰盈盈  梁秀娟 《吉林大学学报(地球科学版)》2004,(Z1)

利用大量实际资料,采用GMS软件建立了白城市洮儿河扇形地立体地质模型,系统研究了区域水文地质条件,应用Surfer软件,采用含水层体积法和水层厚度法计算了地下水库的储存空间,采用动态资料推求、野外试验和室内实验等多种方法确定了主要水文地质参数,重点分析计算了洮儿河扇形地作为地下水库的储水空间、补给水源和调蓄能力,讨论了在该区修建地下水库的可行性及其效果,提出扇形地地下水库设计与建设的有关建议。  相似文献   

A simple accelerated rock weathering method to predict acid generation kinetics     

David M. Kargbo  Jiren He 《Environmental Geology》2004,46(6-7):775-783

The development of effective, and economical pre-development waste rock management plans requires an accurate estimate of the quality of drainage generated during mining. This study was conducted to determine if a simple accelerated rock weathering method with lower capital and personnel costs can be used in lieu of the elaborate and costly ASTM method to predict the quality of drainage generated. It involves subjecting rock samples to a constant relative humidity and temperature for 7 days and leach flooding the weathered samples on the 7th day. The acid production rate from the new weathering method correlates quite well with the net neutralization potential generated from the standard acid-base accounting procedure (R²=0.940) which has been demonstrated to be correct 90% of the time in assessing overburden quality, and a mineralogical method (R²=0.924). For investigators interested in generating weathering kinetic parameters, the simple and less costly accelerated weathering method is proposed.  相似文献   

Conceptual study — An improved method to assess acidification in German streams by using benthic macroinvertebrates     

Ulrich Braukmann  Regina Biss 《Limnologica》2004,34(4):433-450

The present study is based mainly upon the authors' hydrochemical and hydrobiological studies of small silicate streams in South-West Germany, principally in the Black Forest and the Odenwald.

The aim of the paper is the adaptation of a practically proven four-level biological classification system of different degrees of acidity using benthic maroinvertebrates to a five-level system of acidification of mainly upland streams with low buffer capacity. The main reason for such a five-class system is the Water Framework Directive of the European Union (EU WFD), which lays down a five-level classification system for the assessment of the ecological quality of waters.

The biological method of assessing the state of acidity for evaluation of the degree of anthropogenic acidification under the directive, and principles of the EU WFD, are also described. A list of 278 taxa of the macrozoobenthos has been reclassified from a four-level system to a five-level biological indication system, based upon the authors' scientific expertise and the latest references from literature of different acid sensitive areas in Germany.  相似文献   

Capacity evaluation of statnamic tested long piles     

San-Shyan Lin  J. L. Hong  Wei F. Lee  Y. H. Chang 《Soil Dynamics and Earthquake Engineering》2004,24(11):829-838

A procedure that uses the structural damping (SD) concept for estimating the capacity of a pile based on the Statnamic (STN) pile load test results, formerly used by the authors for short piles, is extended in this paper for the STN tested long piles. Similar to segmental unloading point method procedures for long piles, the shaft length is divided into several segments and each segment is assumed to behave as a mass of a single degree of freedom. The SD concept is then applied to each segment to consider the displacement related soil damping instead of the velocity dependent damping. Instrumented strain gauge data at different levels of the shaft are required for the interpretation method. Three case studies are presented in this paper to study the validity and applicability of the present method. The predicted results are also compared to the available test or analytical data.  相似文献   

长春市轻轨工程大漂石地层灌注桩成孔钻进技术          下载免费PDF全文

吴开滨  代国忠 《探矿工程》2004,31(12):12-13

结合长春市轻轨工程斜拉桥钻孔灌注桩施工实例，介绍了大漂石地层的筒钻法钻进原理、潜孔锤钻进工艺、岩心聚能爆破工艺及筒钻回转切石工艺等，为该类地层的顺利成孔成桩总结出了一套切实可行的施工方法。  相似文献   

西藏高原最高、最低气温的非对称变化   总被引：13，自引：2，他引：13       下载免费PDF全文

杜军 《应用气象学报》2003,14(4):437-444

利用中国西藏高原25个台站1971~2000年月平均最高气温 (T_max)、最低气温 (T_min) 及气温日较差 (ΔT)，分析了西藏高原最高、最低气温的非对称变化。结果发现，西藏高原普遍存在非对称变化现象，以T_max、T_min显著上升，但T_min上升幅度大于T_max为主要类型。T_max上升主要表现在夏季，T_min增暖以秋季最为明显，ΔT显著变小主要是由于T_min明显增暖引起的。T_min的上升幅度随海拔高度的上升而增加，T_max在3000~4000 m地区增温最大，而ΔT在4000 m以上呈显著的减小趋势。  相似文献   

Relationship between Droplet pH and Aerosol Dissolution Kinetics: Effect of Incorporated Aerosol Particles on Droplet pH during Cloud Processing     

K. V. Desboeufs  R. Losno  J.L. Colin 《Journal of Atmospheric Chemistry》2003,46(2):159-172

The effect of incorporated aerosols on droplet pH was investigated by dissolution experiments on various particle types. These experiments conducted in an open-flow system show that the pH changes induced by aerosol solubilisation last up to 30 min, in the range of a typical droplet lifetime. These pH changes depend upon the initial pH of the experiment, i.e., the pH at cloud condensation. In the pH range between 3 and 5, the pH varies the most when it is high, since the base agents leached from the particles are neutralised by the protons present in the aqueous phase. A relationship between the neutralising capacity of the aerosol (NCA), i.e., the amount of uncompensated base species, and the pH after neutralisation has been found. Other experiments show that the NCA is related to the aerosol composition: silicates present more or less pronounced NCA, whereas C graphite presents a negative NCA, i.e., an acidifying capacity. The aerosol composition can be modified during cloud evapocondensation, notably by the addition of sulphate or sulphuric acid to the aerosol surface. NCA modification with cloud processing is observed when the amount of dissolved acid is larger than the neutralising capacity of the aerosol, i.e., when the droplet pH is less than a compensation pH characteristic of the aerosol type.  相似文献   

An Incremental Response Spectrum Analysis Procedure Based on Inelastic Spectral Displacements for Multi-Mode Seismic Performance Evaluation   总被引：1，自引：0，他引：1  

M. Nuray Aydinoğlu 《Bulletin of Earthquake Engineering》2003,1(1):3-36

The so-called Nonlinear Static Procedure (NSP) based on pushover analysis has been developed in the last decade as a practical engineering tool to estimate the inelastic response quantities in the framework of performance-based seismic evaluation of structures. However NSP suffers from a major drawback in that it is restricted with a single-mode response and therefore the procedure can be reliably applied only to the two-dimensional response of low-rise, regular buildings. Recognizing the continuously intensifying use of the pushover-based NSP in the engineering practice, the present paper attempts to develop a new pushover analysis procedure to cater for the multi-mode response in a practical and theoretically consistent manner. The proposed Incremental Response Spectrum Analysis (IRSA) procedure is based on the approximate development of the so-called modal capacity diagrams, which are defined as the backbone curves of the modal hysteresis loops. Modal capacity diagrams are used for the estimation of instantaneous modal inelastic spectral displacements in a piecewise linear process called pushover-history analysis. It is illustrated through an example analysis that the proposed IRSA procedure can estimate with a reasonable accuracy the peak inelastic response quantities of interest, such as story drift ratios and plastic hinge rotations as well as the story shears and overturning moments. A practical version of the procedure is also developed which is based on the code-specified smooth response spectrum and the well-known equal displacement rule. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献