西藏某水电站左岸坝肩边坡地震稳定性分析

地震作用下岩质高边坡的稳定性历来是边坡稳定性研究中的重点,难度比较大。总结了对地震边坡进行工程地质分析的方法,并结合西藏某拟建水电站所在区工程地质条件,对地震作用下该水电站的边坡的稳定性进行工程地质分析;建立数值模型,采用有限差分程序FLAC 3D对地震作用下该边坡的动力稳定性进行分析。由工程地质分析可知,该边坡在地震作用下整体处于稳定状态;拟静力法计算可知,地震对该边坡的稳定性有一定影响;通过地震动力时程分析可知,地震对边坡顶部和坡面附近的影响较大,因而这些地方危险较大;同时还分析了地震波频率、振幅对稳定性的影响以及断层对地震波传播的影响规律。     

地下水砷污染研究进展

砷是一种毒性很强的致癌物质,地下水的砷污染严重破坏生态环境,危害人类健康,已成为近年来国内外学者研究的热点问题。本文针对地下水的砷污染问题进行综述,介绍了地下水砷污染研究现状,并简单介绍了地下水中砷的来源。另外,还针对地下水中砷的存在形态及其影响因素等方面作了详细介绍,对砷污染的预防控制和修复治理起到指导作用。     

回填块石土强夯施工工艺的确定及设计优化

以华能莱芜电厂百万机组“上大压小”扩建工程填方区回填块石土强夯地基处理试夯试验为例,比对2个试夯分区采用不同施工工艺施工的质量差别及处理效果,据此查明强夯法的施工质量,确定强夯有效加固深度、土的密实度、变形参数和地基承载力等。根据场地夯填厚度,选取合适的虚填厚度及相应的施工工艺,确定最终施工方案,进一步提高强夯地基处理效果,为最终确定大面积施工所采用的施工工艺提供依据。     

Accuracy and reliability-based region-specific recalibration of dynamic pile formulas

Many state departments of transportation and consulting firms continue to use dynamic formulas because they are simple and inexpensive as compared to the preferred dynamic loading test with signal matching. Efforts to reduce the error and uncertainty associated with dynamic formulas are therefore warranted until dynamic monitoring becomes standard for every driven pile. However, dynamic formulas calibrated to national test pile databases have indicated inaccuracy and high uncertainty in the capacity prediction using dynamic formulas. A region-specific dynamic load test database was used to assess the accuracy and uncertainty in the Janbu, Danish and FHWA Gates formulas, recalibrate the equations for local conditions (construction practice, geology) and to generate resistance factors for use with Load and Resistance Factor Design (LRFD). Following recalibration, the capacity predictions became more accurate, and an observed dependence of the accuracy on the magnitude of resistance was eliminated for most driving conditions (e.g. end-of-driving, restrike). Previously reported static load test data were used to incorporate the transformation error associated with using the dynamic capacity to predict an equivalent static capacity. Resistance factors for use in Load and Resistance Factor Design (LRFD) were developed in consideration of American Association of State Highway and Transportation Officials–recommended load statistics and target reliability indices. Efficiency factors were used to assess the economic performance of each dynamic formula. Comparison of the accuracy and uncertainty of the recalibrated equations to a nationwide calibration illustrated the advantage of using a geologic-specific database for the calibration of resistance factors.     

Approximate analytical and numerical solutions for radial non‐Darcian flow to a well in a leaky aquifer with wellbore storage and skin effect

This study investigated non‐Darcian flow to a well in a leaky aquifer considering wellbore storage and a finite‐thickness skin. The non‐Darcian flow is described by the Izbash equation. We have used a linearization procedure associated with the Laplace transform to solve such a non‐Darcian flow model. Besides, the Stehfest method has been used to invert the Laplace domain solutions for the drawdowns. We further analyzed the drawdowns inside the well for different cases. The results indicated that a smaller B_D results in a smaller drawdown at late times and the leakage has little effect on the drawdown inside the well at early times, where B_D is a dimensionless parameter reflecting the leakage. We have also found that the flow for the negative skin case approaches the steady‐state earlier than that for the positive skin. In addition, the drawdown inside the well with a positive skin is larger than that without skin effect at late times, and a larger thickness of the skin results in a greater drawdown inside the well at late times for the positive skin case. A reverse result has been found for the negative skin case. Finally, we have developed a finite‐difference solution for such a non‐Darcian flow model and compared the numerical solution with the approximate analytical solution. It has been shown that the linearization procedure works very well for such a non‐Darcian flow model at late times, and it underestimates the drawdowns at early times. Copyright © 2012 John Wiley & Sons, Ltd.     

利用地震相变化推测地质演化规律

蔚县矿区是一个中生代赋煤区,通过对单侯矿区西南翼三维地震数据体的认识,认为该区煤层基底为寒武系、奥陶系下统,受海西期与印支期抬升作用的影响,缺失了中奥陶统至三叠系。煤层的基底隆起形成于印支期,即使在接受成煤沉积的燕山期,基底仍处于不均匀的抬升状态。成煤期间,由于盆地基底抬升或沉降幅度不均衡,导致了蔚县整个含煤盆地内部沉积厚度发生变化,造成隆起部位煤层变薄及缺失。后期随着抬升的延续,结束了该区含煤建造过程。     

地质模型约束下的地震储层预测技术及其在梨树断陷中的应用

在钻测井约束下,结合梨树断陷有关探井资料和区域性沉积相研究,综合运用调谐频率加强法高分辨率处理技术和基于地震资料的时频分析技术、地震相技术、多属性分析技术及基于层序框架下的地震资料解释技术等,采取拟声波曲线重构地震反演技术和基于调谐频率加强法的高分辨率反演方法等,研究目的层岩性、物性和含油气性。同时,结合基于地震属性分析的人工智能技术的储层物性预测方法,预测砂体的空间分布和几何形态,落实隐蔽圈闭,完成了滚动勘探和开发2个阶段不同井区有利砂体分布规律评价及预测工作。     

核安全相关边坡与一般边坡挡土墙抗震稳定性验算对比分析

在挡土墙稳定性计算基本原理基础上, 引入《核电厂抗震设计规范》(GB 50267-97) 关于地震系数的规定, 重新建立了安全相关边坡挡土墙土压力和地震角计算公式, 并应用到实际工程中。对比分析显示, 挡土墙按核安全边坡和一般边坡进行抗震验算时, 地震系数、地震角的取值相差较大; 由于按核安全边坡计算时地震力远大于一般边坡, 因此稳定系数远小于一般边坡。     

基于Matlab/GUI的钻机动力头齿轮动态优化设计

煤矿用全液压钻机动力头主要采用液压驱动和齿轮传动相结合的方式,其中,齿轮传动的振动烈度直接影响着动力头的输出能力,成为了设计中必须考虑的重要问题。以ZYWL-2600R型松软煤层螺旋钻机为研究对象,在齿轮副的单自由度扭转振动模型基础上,以啮合线上的振动加速度为优化目标,建立了动力头齿轮副的动态优化设计模型,并借助Matlab优化工具箱和GUI工具开发了优化设计程序的图形界面,求解了齿轮振动最小的宏观设计参数,为钻机“高速”动力头的动态优化设计提供了参考。结果表明,优化后齿轮副的时变啮合刚度显著提高,有效改善了齿轮传动的振动特性。     

The Energy Relationship between Ions and Soil Particles based on Wien Effect and Its Application in Soil Science

The interaction between ions and soil particles plays an important role in the mobilization and bioavailability of ions in soils, which is one of the main research areas of soil chemistry. The new method based on suspension Wien effect has been developed recently to determine the binding energy and adsorption energy between ions and soil particles. Compared with other methods on the basis of adsorption isotherm or ions activity, Wien effect method has more advantages including convenience and direct measurement. The term suspension Wien effect refers to the increase of electrical conductivity of suspension with increasing applied electrical field. In this review paper, we introduced the fundamentals of suspension Wien effect, the apparatus about the Wien effect measurement, and along with demonstrating their application to quantifying the particles-ions interactions for several systems of soils. Our studies indicated that divalent cations have larger binding energies and adsorption energies on soil particles than monovalent because of the electrostatic interaction. However, few studies about the interaction between Cr³⁺ and La³⁺ on soil particles showed that the binding energy and adsorption energy of trivalent cations are lower than those of divalent cations because of hydrolysis. Soil properties such as soil organic matter, soil pH, and iron oxides significantly affected the binding energy and adsorption energy of ions. Our results deepened our understanding about the non specific adsorption of ions in soil chemistry, and enlarged the research area of soil chemistry in fundamental and methodology.