土钉支护施工阶段土钉轴力的计算分析

土钉支护的形成过程对其受力和变形有直接影响。结合土钉支护边开挖、边支护且开挖在前的施工特点,定义开挖影响面以反映土体开挖时边坡滑动趋势的变化,与开挖影响面相交处的土钉在土体开挖时轴力增加最多。开挖土压力表示以开挖影响面为边界的土块体产生的土压力,由相邻两步开挖土压力之差求得挖土引起的不平衡力。增加的土钉轴力在平衡此不平衡力的同时,维持着边坡稳定。据此,以开挖影响面及其土钉轴力增量为主要研究对象,提出了施工阶段土钉轴力的分析方法。该方法在求得土钉轴力最大值及其作用位置的同时,还给出了土钉轴力沿钉长方向的分布。应用此方法对法国CLOUTERRE项目1号墙足尺试验进行了计算,结果表明：计算与测试结果吻合良好。     

对台湾强震的预警时间研究

The paper collects the records by the Fujian Digital Seismic Network of 40 shallow earthquakes in Taiwan with M_S≥5.0 from 1999 to 2013,analyzes the seismic phase(Pn,Sn phase)characteristics and travel-time rules,determines travel-time models and develops a seismic phase travel-time equation based on the two-step fitting algorithm.With the deduction of processing time and network delay time,this method can provide an accurate estimation of early warning time of Taiwan earthquakes for the Fujian region,and has been officially employed in the earthquake early warning system of Fujian Province.     

2018年南黄海浒苔绿潮迁移发展规律与营养盐相互关系探究

根据2018年4月(春季,绿潮前期)和7月(夏季,绿潮后期) 南黄海营养盐、温度、盐度等水文参数及每日绿潮卫星监测数据,深入分析2018年绿潮的发展规律与营养盐结构特征之间的关系。结果表明：4月25在江苏南通外海首次发现浒苔绿潮,8月中旬在山东半岛近海消亡,其发展区域集中在122°E以西近海,且快速增殖阶段处在35°N以南江苏近海。各组分的营养盐浓度受沿岸径流、冷水团及生物作用等因素影响,均呈现江苏近海高外海以及北部低的特征。对比绿潮发展和营养盐分布呈现3个明显的绿潮−营养盐特征区域：高营养盐−绿潮快速发展区域(35°N以南,122°E 以西,江苏近海);低营养盐−绿潮消亡区域(35°N以北,122°E 以西,山东半岛外海域)及122°E以东外海无绿潮区域。不同特征区营养盐变化表明,江苏近岸较高的营养盐含量(${\rm{NO}}_3^- $-N>6.5 μmol/L, ${\rm{PO}}_4^{3-} $-P>0.27 μmol/L)和丰富来源是浒苔萌发和绿潮快速发展的重要物质基础,为绿潮发展提供了主要的氮、磷生源要素。北部山东半岛南外海较低的营养盐水平(7月,DIN<2 μmol/L, ${\rm{PO}}_4^{3-} $-P<0.03 μmol/L)是限制绿潮继续发展的重要因素。     

对东北深震震相特征和地震参数的对比分析

对兰州地震台数字化和模拟记录并行期间,发生在中国东北的2个具有典型深震特征的中强地震,进行了数字与模拟(DK1)记录对比分析,以便快速、准确的速报其地震参数,提高兰州地震台对深震的快速反应能力.     

Phases of Environmental Evolution Indicated by Primary Chemical Elements and Paleontological Records in the Upper Pleistocene-Holocene Series for the Salawusu River Valley, China

Studies of lithology, sedimentary facies and the distribution regularity of SiO2 and Al2O3 contents and Al2O3/SiO2 ratio allow us to divide the Upper Pleistocene-Holocene Series represented by the MUanggouwan section in China＇s Salawnsu River valley into six segments： MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6. The boundary ages for MGS1 （the Dishaogouwan and Dagouwan Formations）, MGS2 （the upper Chengchuan Formation）, MGS3 （the middle Chengchuan Formation）, MGS4 （the lower Chengchuan Formation）, MGS5 （most strata of the Salawusu Formation） and MGS6 （the bottom of the Salawusu Formation and the top of the Lishi Formation） correspond to those of MIS1, MIS2, MIS3, MIS4, MISS and MIS6, respectively, from deep sea sediments or continental glaciers. MGS5 can be subdivided into five subsegments （MGS5a, MGS5b, MGS5c, MGS5d and MGS5e） and the boundary ages of these subsegments correspond to those of MISSa, MISSb, MIS5c, MIS5d and MIS5e, respectively. Based on the paleoenvironment and paleoecology indicated by the primary chemical elements, fossil vertebrates, mollusks and pollen grains, we hypothesize that MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6 and the subsegments of MGS5 match the corresponding stages for oxygen isotopes in the deep sea sediments and continental glaciers, and the substages of MIS5 in terms of climatic characters, further explaining the phenomena that determined the formation of the late Quaternary strata and the paleontology of the Salawusu River valley. These phenomena relate to fluctuations in the global climate （and particularly in the East Asian monsoon） during the glacial and interglacial periods.     

贵州前寒武系区域变质岩的主要变质时期

贵州前寒武系变质岩主要有区域变质岩。区域变质作用有两上重要的递进发展阶段,有泥盆纪时期的埋深静压变质作用和燕山期的动压变质作用。     

First-principles study of (MgH2SiO4)? n (Mg2SiO4) hydrous olivine structures. I. Crystal structure modelling of hydrous olivine Hy-2 a (MgH2SiO4) ? 3(Mg2SiO4)

 Recently, the Hy-2a hydrous olivine (MgH₂ SiO₄)·3(Mg₂SiO₄) occurring as nanometre-sized inclusions in mantle olivines has been found by TEM, and has been suggested to be a new DHMS phase (Khisina et al. 2001). A model of the crystal structure of Hy-2a has been proposed as a 2a-superstructure of olivine with one Me²⁺ -vacant octahedral layer in the (1 0 0) plane per Hy-2a unit cell (Khisina and Wirth 2002). In the present study the crystal structure of Hy-2a hydrous olivine is optimized by ab initio calculations. The aims of this study are: (1) verification of the suggested models of Hy-2a hydrous olivine structure; (2) calculation of the most stable configurations for Hy-2a structure with minimum static lattice energy, by assuming a possible formation of Me²⁺ vacancies in either M1 or M2 octahedral sites; (3) determination of the position of protons and hydrogen bonds in the Hy-2a structure. Several different possible configurations of the Hy-2a structure are optimized. The results support the idea of a stable olivine structure with ordered planar-segregated OH-bearing defects oriented parallel to (1 0 0). The data obtained indicate a preferred stability of the Hy-2a structure with the protons associated with M1 vacancies and bonded with O1 and O2 oxygen sites. The relative energy values of the optimized Hy-2a structure configurations correlate as a rule with the average shifts of atoms from their positions in pure forsterite structure. Received: 7 February 2002 / Accepted: 23 October 2002     

骨炭钝化含黄铁矿多重金属尾矿的研究

钝化处理被广泛应用于含重金属尾矿的处理,可以从源头上防止酸矿废水(AMD)的产生,寻找一种价廉易得且对环境危害小的钝化剂十分必要。本文主要研究在骨炭作用下,用pH值为4的双氧水对黄铁矿进行氧化,探讨骨炭对黄铁矿氧化释放重金属的钝化作用。实验结果表明,添加不同含量的骨炭(分别为0.5、2.5和5 g)能将溶液的pH值分别提高到8.93、10.01和10.42,表明骨炭具有较强的中和能力,同时黄铁矿氧化释放的Pb、Zn和Cd等重金属离子浓度明显地降低。但当骨炭含量超过2.5 g时,对As有促进释放的趋势。红外光谱分析显示钝化后黄铁矿样品位于420、563、603、1 044、1 091 cm~(-1)处的特征峰主要来自PO_4~(3-)的振动,XRD进一步揭示了黄铁矿表面主要含磷次生矿物是磷铁矿和羟磷铁铅石,这些次生矿物对重金属钝化起着重要作用。因此,骨炭有望作为钝化含多重金属尾矿的钝化剂。     

地幔中水的存在形式和含水量

水以含水变质矿物、无水硅酸盐矿物(橄榄石、辉石等)及其高压结构相(β橄榄石、γ橄榄石、钙钛矿相、方镁铁矿等)、高密度含水镁硅酸盐和熔体的形式存在于地幔各层圈中。根据各类玄武岩水含量推断出的上地幔源区的水含量,和由地幔岩主要矿物———橄榄石的水含量估算出的上地幔水含量(质量分数)很接近,在0.02%左右。以橄榄石和辉石高压相的水含量为依据,进行了过渡带和下地幔水含量的估算,其结果是:过渡带和下地幔上部的水含量(质量分数)为1.48%,下地幔下部水含量(质量分数)为0.21%。据此,计算出的地幔各层圈的总水量表明,地幔水的74%以上存在于过渡带和下地幔上部。将地幔总水量和现代海洋总水量之和作为地球总水量,计算出现代海洋总水量约占全球总水量(质量分数)的6.6%,这个结果与笔者根据地球的球粒陨石成分模型计算出的总水量(6%)十分接近。     

层间氧带砂岩型铀矿床的铁物相特征及其地球化学意义——以伊犁盆地511铀矿床和吐哈盆地十红滩铀矿床为例

层间氧化带砂岩型铀矿床在空间上与层间氧化带各亚型的分布具有严格的对应关系。铁元素的物相特征是所处地球化学环境变化的敏感标志，FeFe2O3/TFe,Fe(FeCO3 FeS2)/TFe,FeFe2O3/Fe(FeCO3 FeS2)等比值是反映地球环境变化的重要指标，应用铁物相特征及其以上比值，可以简捷地对层间氧化带进行亚带的划分，这对指导铀矿勘查具有重要理论和实践意义，过渡带中菱铁矿（FeCO3)和黄铁矿（FeS2)等对地球化学环境敏感的矿物的富集，指示了有利于铀成矿的中性－弱酸性，还原的地球化学环境。