遥感图像在复杂地形下矿山监测中的应用研究——以云南安宁矿区为例

随着我国经济的飞速发展,对资源的需求量越来越大,矿产资源是主要的能源供应,因此矿产资源的开发监测变得尤为重要。该文将地形比较复杂的云南安宁矿区作为研究对象,论证了遥感图像在复杂地形下的矿山监测中的应用,认为相对目前采用的传统监测手段,遥感图像在时效性、效率、成本等多方面存在很多优势。     

Large‐scale seismic tests of tall concrete bridge columns with precast segmental construction

Past experimental studies have shown that existing precast segmental concrete bridge columns possess unsatisfactory hysteretic energy dissipation capacity, which is an undesirable feature for applications in seismic regions. In this research, we propose new methods of precast segment construction for tall concrete bridge columns to enhance the columns' hysteretic energy dissipation capacity and lateral strength. This is accomplished by adding bonded mild steel reinforcing bars across the segment joints, strengthening the joint at the base of the column and increasing the height of the base segment (hinge segment). Four large‐scale column specimens were fabricated and tested with lateral cyclic loading in the laboratory. Each specimen consisted of a foundation and 9 or 10 precast column segments. Test results of specimens with the proposed design concepts showed ductile behavior and satisfactory hysteretic energy dissipation capacity. In addition to the experimental study, an analytical study using the finite element method was conducted to understand the bond conditions, strain contours and deformation patterns of the specimens tested. Good agreement was found between the experimental observations and the results of the calibrated analytical study. Copyright © 2008 John Wiley & Sons, Ltd.     

Fossil gastropods from the MGS3 stratigraphic segment in the Salawusu River Valley and their climatic and environmental implications

Contemporaneous with MIS3, the MGS3 segment of the Milanggouwan stratigraphic section in the Salawusu River Valley, Mu Us Desert, China contains fossil gastropods (terrestrial and freshwater snails) in strata 33LS, 35LS, 37FL and 39LS. Examination of these fossils revealed 11 species belonging to 8 families and 10 genera. They can be classified as: (1) assemblage of Gyraulus and Galba mainly consisting of Gyraulus convexiusculus, Gyraulus sibiricus, Galba pervia and Galba superegra Gredler, etc. (2) assemblage of Vallonia mainly consisting of terrestrial snails, such as Vallonia patens, Pupilla muscorum and Discus paupe, etc. Based on the dating results, and the living habits, living conditions, and geographic distribution of their extant species, we suggest that: the ages of 33LS, 35LS, 37FL, and 39LS are 26000, 29000, 33000 and 38000 a, respectively, corresponding well to the interstadial period in GRIP 4, 5, 6 and 10 in terms of chronology and climatic characters; 33LS, 35LS and 39LS represent very warm-humid periods, while 37FL represents a less warm-humid period; the four periods of climatic fluctuations recorded in MGS3 were related to the strong impact of the summer monsoon in East Asia in Mu Us Desert of China during the interstadial of MIS3 on a global climatic background.     

川西绵竹地区构造特征及对油气成藏控制作用

绵竹主体构造为龙门山前构造带关口隐伏断裂的下盘构造,构造样式为研究区断滑褶皱,形成于印支期,在喜山期遭受了一定程度的调整改造,为一古今叠合构造。对研究区构造特征及演化分析表明,构造形成及其演化对研究区圈闭类型、储层发育、油气运移通道有着强烈的控制作用,是绵竹构造油气成藏和富集的主要控制因素。多期构造运动形成的不整合面及断裂为油气运移提供了良好的通道,有效改善了储层孔渗条件,形成的断背斜、背斜为油气聚集成藏提供了良好的场所。     

Potential of quartz OSL dating on moraine deposits from eastern Tibetan Plateau using SAR protocol

Optically stimulated luminescence (OSL) dating methods have been widely applied in Quaternary glaciology. However, glacigenic deposits are considered in general as problematic for OSL dating, mainly because they are transported shorter distances prior to burial and are usually partially bleached. Thus, most researchers choose glaciofluvial and glaciolacustrine sediments (with relatively longer transportation times) for OSL dating when constraining the age of glaciation. In this study, four samples were collected from a lateral moraine series at Zhuqing Village, northern margin of Queer Shan Mountain, eastern Tibetan Plateau, in order to investigate the applicability of OSL dating for morainic deposits. Quartz grains (38–63 μm) were extracted and measured using single aliquot regenerative-dose (SAR) protocol. Internal checks and dose recovery test show that the SAR protocol is appropriate for equivalent dose (D_e) determination. The effect of thermal transfer is small for all samples and the recycling ratio for each individual sample is close to unity. The symmetry in the D_e distributions indicates that quartz grains were well-bleached prior to burial. OSL ages show good agreement with geomorphological and field investigations, and are also concordant with an independent ESR age. It is concluded that: (a) the morainic deposits in Zhuqing were well-bleached and suitable for OSL dating; (b) SAR protocol can be applied to morainic deposits for samples under study.     

汶川8.0级地震中长期预测及跟踪短期预测探讨

1999年,笔者发表了对2008年中国汶川8级地震的中长期预测结果,预测的最危险地区为汶川,上限震级为7.2级(实际震级8.0,误差0.8级),危险时段为2007—2012年、2021年以后(实际地震发生在第一危险时段内)。本文对预测方法做了概要介绍,总结了方法的特点,提出了改进意见,并探讨了跟踪短期预测方法。     

A parametric study of seismic behavior of roller seismic isolation bearings for highway bridges

A roller seismic isolation bearing is proposed for use in highway bridges. The bearing utilizes a rolling mechanism to achieve seismic isolation and has a zero post‐elastic stiffness under horizontal ground motions, a self‐centering capability, and unique friction devices for supplemental energy dissipation. The objectives of this research are to investigate the seismic behavior of the proposed bearing using parametric studies (1) with nonlinear response history analysis and (2) with equivalent linear analysis according to the AASHTO guide specifications, and by comparing the results from both analysis methods (3) to evaluate the accuracy of the AASHTO equivalent linear method for predicting the peak displacement of the proposed bearing during an earthquake. Twenty‐eight ground motions are used in the studies. The parameters examined are the sloping angle of the intermediate plate of the bearing, the amount of friction force for supplemental energy dissipation, and the peak ground acceleration levels of the ground motions. The peak displacement and base shear of the bearing are calculated. Results of the studies show that a larger sloping angle does not reduce the peak displacement for most of the parametric combinations without friction devices. However, for parametric combinations with friction devices, it allows for the use of a higher friction force, which effectively reduces the peak displacement, while keeping a self‐centering capability. The AASHTO equivalent linear method may underestimate the peak displacement by as much as 40%. Vertical ground motions have little effect on the peak displacement, but significantly increase the peak base shear. Copyright © 2009 John Wiley & Sons, Ltd.     

A1B情景下东亚地区未来春季沙尘变化趋势预估

采用区域气候与沙尘耦合模式RegCM4-Dust,模拟研究了A1B情景下东亚地区未来（2015-2100年）春季沙尘变化趋势。结果表明：（1）总体上,东亚沙尘源区起尘通量与沉降通量存在明显的振荡特征,而沙尘光学厚度呈现显著的波动减小趋势;源区下游沙尘光学厚度和沉降通量均呈现显著的波动增大趋势。（2）沙尘子源区中,仅塔克拉玛干沙漠及周边地区起尘通量有显著波动减少趋势,速度达-2.1%/10a;萨雷耶西克阿特劳沙漠和呼伦贝尔沙地沙尘光学厚度减小速度最快,分别达到-2.8%/10a、-2.3%/10a。（3）未来,中国华北南部、黄淮以及长江中下游地区以及中国东、南部近海春季沙尘光学厚度增速均为1.5%/10a;中国近海沙尘沉降通量显著上升,速度达1.9%/10a。（4）地面风速尤其是最大风速变化是导致起尘通量变化的主要因素,而影响光学厚度的主要因素是地面最大风速。     

对部分简单形体产生的自然电位进行定量分析

本文提出了一种新的特征点法,并在前人的基础上改进了一种数值计算方法(最小二乘法),以此来确定部分具有自然电位异常简单地质体的形态(形态系数)、埋藏深度、极化角和电偶极矩。特征点法通过剖面上三个特殊点(两个极值点和零电位点)的值以及它们相互间的距离便可快速求取地质体各参数。改进的最小二乘法则是在前人的基础上加入了零电位点的计算及其它处理方法,以此来获得准确性更高的地质体各参数。两种方法都被用来计算加入±5%随机误差的理论模型数据,并在土耳其的一个实际野外数据中得到测试。结果表明所求的参数与实际参数具有较好的一致性。     

广州市似大地水准面精化的研究

阐述广州市似大地水准面精化的目的及意义,明确该项目的总体目标,以及实施的技术方案.