昌马水库右岸山体稳定性研究   总被引：2，自引：0，他引：2  

杨健  陈祖煜  何传永 《水文地质工程地质》2004,31(1):24-27

昌马水库导流排砂洞塌方导致右岸山体发生松动 ,本文在大量地质资料的基础上 ,对右岸岩体裂隙网络进行模拟 ,同时 ,采用极限分析能量法和有限元数值模拟方法等对右岸山体的稳定性进行分析研究 ,并提出相应的加固方案。  相似文献   

吉林台水电站厂房高边坡稳定性及加固措施研究   总被引：2，自引：0，他引：2  

杨健  耿克勤 《水文地质工程地质》2004,31(2):41-44

吉林台水电站厂房后边坡开挖形成140～340m的高边坡,保证其长期运行稳定性至关重要。在结合地质资料对边坡的失稳模式进行初步判断的基础上,采用极限平衡分析方法对正常蓄水、暴雨影响、地震荷载等工况条件下边坡的整体抗滑稳定性进行分析,得出暴雨对边坡稳定影响较大的结论,据此提出以排水结合预应力锚索为主的边坡加固增稳措施,实践证明该措施是有效的。  相似文献   

新疆富蕴县柯鲁木特锂-钽-铌矿床228号脉地质特征分析   总被引：1，自引：0，他引：1  

李泰德  程剑 《矿产与地质》2004,18(5):428-431

通过对柯鲁木特锂-钽-铌矿床228号矿脉的普查，发现该矿脉锂、钽、铌的含量较高，矿脉规模大。为了进一步在该区开展找矿工作，阐述了228号含矿伟晶岩脉的共生结构分带的产出特征、结构带内部特征、稀有元素含量变化及其不同矿化类型等，在总结了228号及其相似的113号、116号含矿伟晶岩脉成矿地质背景的基础上，指出伟晶岩的主要形成阶段和矿化阶段是在一个比较封闭的地质环境中生成的，并认为含矿伟晶岩脉的形成与二云母二长花岗岩有着密不可分的关系。  相似文献   

土工织物加固软土路堤的有限元分析   总被引：5，自引：4，他引：5  

刘春虹  肖朝昀  王建华  陈锦剑 《岩土力学》2004,25(Z2):325-328

采用有限元方法对土工织物加固软弱地基路堤的力学机理进行了研究.通过比较路基加筋和未加筋两种情况研究了土工织物的加固机理,结果表明土工织物对于提高路堤填筑高度、减少路堤侧向位移、均化路堤沉降以及加速超孔隙水压力消散有显著的效果.加筋路堤中土工织物的轴力受填筑高度、超孔压消散速度和接触面系数等因素的影响,路堤填筑高度和施工进度的控制有利于土工织物抗拉强度的发挥.对路堤安全系数的研究分析表明传统的极限平衡法验算路堤稳定性偏于保守,采用有限元方法能较好地反映土工织物的加筋作用,可以优化工程设计.  相似文献   

安徽铜陵新桥铜-硫-铁-金矿床中石英闪长岩和辉绿岩锆石SHRIMP年代学及其意义   总被引：48，自引：3，他引：48       下载免费PDF全文

王彦斌刘敦一  蒙义峰曾普胜杨竹森  田世洪 《中国地质》2004,31(2):169-173

对安徽铜陵新桥铜-硫-铁-金矿床区内的石英闪长岩和辉绿岩中的锆石分别进行了SHRIMP精确定年研究,石英闪长岩中锆石206Pb/238U年龄为(140.4±2.2)Ma,辉绿岩中锆石的年龄较复杂,其中发现了元古代锆石颗粒,其锆石207Pb/206Pb年龄为(2261±14)Ma,(1612±8)Ma,(919±12)Ma,(831±17)Ma。另外还有一组早古生代年龄的锆石,锆石206Pb/238U年龄为(443±13)Ma。以上这些新资料说明该区可能存在元古代基底的信息,且燕山期岩浆活动对本区成矿具有重要意义。  相似文献   

A Corrected and Generalized Successive Random Additions Algorithm for Simulating Fractional Levy Motions     

Hui-Hai Liu  Gudmundur S. Bodvarsson  Silong Lu  Fred J. Molz 《Mathematical Geology》2004,36(3):361-378

Simulation of subsurface heterogeneity is important for modeling subsurface flow and transport processes. Previous studies have indicated that subsurface property variations can often be characterized by fractional Brownian motion (fBm) or (truncated) fractional Levy motion (fLm). Because Levy-stable distributions have many novel and often unfamiliar properties, studies on generating fLm distributions are rare in the literature. In this study, we generalize a relatively simple and computationally efficient successive random additions (SRA) algorithm, originally developed for generating Gaussian fractals, to simulate fLm distributions. We also propose an additional important step in response to continued observations that the traditional SRA algorithm often generates fractal distributions having poor scaling and correlation properties. Finally, the generalized and modified SRA algorithm is validated through numerical tests.  相似文献   

Kinetic-simulating experiment combined with GC-IRMS analysis: application to identification and assessment of coal-derived methane from Zhongba Gas Field (Sichuan Basin, China)   总被引：2，自引：0，他引：2  

Yongqiang Xiong  Ansong Geng  Jingzhong Liu 《Chemical Geology》2004,213(4):325-338

The main purpose of this study is to model the δ¹³C values of methane derived from coal by combining kinetic-simulating experiment with the gas chromatography-isotope ratio mass spectrum (GC-IRMS) analysis. The stable carbon isotopic variation of methane in pyrolysates with heating temperature indicates that the assumptions for both a constant kinetic isotope effect (α) and a uniform initial isotopic composition (δ¹³C_o) are impractical for explaining the carbon isotopic fractionation during coalification. For purposes of simplification, two approaches are used in this paper to deal with the heterogeneity of terrestrial organic matter. One is that, assuming a uniform initial isotopic composition (i.e., δ¹³C_{i, o}=δ¹³C_o) for all methane-generating precursors in coal, the isotopic variation of methane is fitted by adjusting ΔE_{a, i} (E_{a¹³C, i}−E_{a¹²C, i}) for each hypothetical reaction. The other is that, assuming a constant kinetic isotope effect during the whole gas formation, that is all ΔE_{a, i} values are identical, the modeling of methane isotopic composition is achieved by changing the ¹³CH₄ generation potential of each reaction (f_{i, ¹³C}), namely, by adjusting the initial δ¹³C value (δ¹³C_{i, o}) for each methane-generating precursor. Results of the kinetic calculation shows that the two simulating methods can yield a similar result at a geological heating rate of 2 °C/My, which further demonstrates that those natural gases with methane δ¹³C value being approximately −36‰ are possibly sourced from the upper Triassic coal measure strata in the Northwestern Sichuan Basin.  相似文献   

Estimating coefficients of volume compressibility from compression of strata and piezometric changes in a multiaquifer system in west Taiwan     

Chih-Hsi Liu  Yii-Wen Pan  Wei-Cha Hung 《Engineering Geology》2004,75(1):33-47

This paper estimates the coefficients of volume compressibility from variation in compressible layer thickness and changes in piezometric heads by using detail ground surface surveys and a multilayer monitoring well at a selected site (Shigang) within the Choshui River alluvial fan in west Taiwan. The paper integrates various types of in situ monitoring tools, including leveling surveys, continuous global position system (GPS) stations, multilevel layer compression and groundwater pressure head-monitoring wells, to investigate the situation and progress of the subsidence problem in the region. The results from the cross-analyses of the measured data show that surface settlement caused by the compression of strata is between the depths of 60 and 210 m where the clayey stratum within 120-180 m was most pronounced and contributes up to 53% of the total compression. The results indicate that the clayey stratum is under normal consolidation. The results also reflect the fact that 20% of settlement contribution comes from the sandy stratum within 90-120 m; the elasto-plastic behavior of this sandy stratum is clear. The coefficients of volume compressibility of the clayey and sandy stratum analysed from the stratum's compression records; they were 6.38×10⁻⁸ and 5.71×10⁻⁹ m²/N, respectively. Ultimately, this parameter estimation would permit to control and predict land subsidence based on change in pressure head which are related to groundwater extraction.  相似文献   

On the long-term seismic hazard analysis in the Zhangjiakou–Penglai seismotectonic zone, China     

Zhengxiang Fu  Jie Liu  Guiping Liu 《Tectonophysics》2004,390(1-4):75-83

The Zhangjiakou–Penglai seismotectonic zone (ZPSZ) lies in the northern part of North China and extends along the Zhangjiakou–Beijing–Tianjin–Bohai Bay–Penglai–Yellow Sea. It is about 900 km long and some 250 km wide in a northwest direction. The great Sanhe-Pinggu (M_S=8.0) earthquake occurred on September 1679 and the Tangshan (M_S=7.8) earthquake on July 1976 caused serious economic and life losses. According to some differences in crust structure and regional tectonic stress field, the ZPSZ is divided into western and eastern segment by the 117°E line for study on long-term seismic hazard analysis. An analysis of Gutenberg–Richter's empirical relation of earthquake-frequency and time process of historic and recent earthquakes along the eastern and western segments shows that the earthquake activity obeys a Poisson process, and these calculations indicate that the earthquake occurrence probability of M_S=6.0–6.9 is 0.77–0.83 in the eastern segment and the earthquake occurrence probability of M_S=7.0–7.9 is 0.78–0.80 in the western segment of the ZPSZ during a period from 2005 to 2015.  相似文献   

Quasi-simultaneous VLBI and RATAN-600 observations of active galactic nuclei     

A. B. Pushkarev  Yu. Yu. Kovalev  I. E. Molotov  M. B. Nechaeva  Yu. N. Gorshenkov  G. Tuccari  C. Stanghellini  X. Hong  J. Quick  S. Dougherty  X. Liu 《Astronomy Reports》2004,48(11):900-908

VLBI observations of several quasars and BL Lacertae objects were carried out at 1.66 GHz in November–December 1999 using six antennas (Medvezh'i Ozera, Svetloe, Pushchino, Noto, HartRAO, and Shanghai). Maps of six sources (0420+022, 0420-014, 1308+326, 1345+125, 1803+784, and DA 193) obtained with milliarcsecond resolution are presented and discussed, together with their broad-band (1–22 GHz) spectra obtained on the RATAN-600 radio telescope at epochs close to those of the VLBI observations. Comparison of the VLBI maps with maps of these sources obtained on standard VLBI networks and with the RATAN-600 quasisimultaneous total-flux measurements indicates the reliability of the results obtained on this Low Frequency VLBI Network and the good efficiency of this network.  相似文献