定水头注水引起的含水层水平运动和应变

基于含水层固体颗粒与孔隙水不可压缩的假设 ,本文导出了单井注水情况下泰斯承压含水层水平运动速度与水头之间的基本关系式。然后利用注水井壁处的应力、应变边界条件 ,进一步导出了单井定水头注水引起的泰斯承压含水层水平运动速度、位移和应变解析表达式。该水平位移与应变由两部分组成 :一部分为由注水压力本身引起的经典弹性力学解项 ,它仅随半径而变化 ,与注水时间无关 ;另一部分为由地下水头变化引起的水动力学位移和应变解项。其中 ,含水层水动力学水平位移随时间加长呈指数增长特征 ,水动力学径向应变则表现为近井处拉张、远井处挤压的分区特征 ,且近井拉张区随时间加长逐渐向外扩展。单井注水含水层水动力学水平位移、应变解的导出 ,完善和发展了单孔内压经典弹性平面力学问题解     

湘江中下游农田土壤和蔬菜的重金属污染

A total of 219 agricultural soil and 48 vegetable samples were collected from the midstream and downstream of the Xiangjiang River（the Hengyang-Changsha section）in Hunan Province.The accumulation characteristics,spatial distribution and potential risk of heavy metals in the agricultural soils and vegetables were depicted.There are higher accumulations of heavy metals such as As,Cd,Cu,Ni,Pb and Zn in agricultural soils,and the contents of Cd（2.44 mg kg^-1 ）,Pb（65.00 mg kg^-1 ）and Zn（144.13 mg kg^-1 ）are 7.97,3.69 and 1.63 times the corresponding background contents in soils of Hunan Province,respectively. 13.2%of As,68.5%of Cd,2.7%of Cu,2.7%of Ni,8.7%of Pb and 15.1%of Zn in soil samples from the investigated sites exceeded the maximum allowable heavy metal contents in the China Environmental Quality Standard for Soils（GB15618-1995,Grade Ⅱ）.The pollution characteristics of multi-metals in soils are mainly due to Cd.The contents of As,Cd,Cu,Pb and Zn in vegetable soils are significantly higher than the contents in paddy soils.95.8%, 68.8%,10.4%and 95.8%of vegetable samples exceeded the Maximum Levels of Contaminants in Foods（GB2762-2005）for As,Cd,Ni and Pb concentrations,respectively.There are significantly positive correlations between the concentrations of Cd,Pb and Zn in vegetables and the concentrations in the corresponding vegetable soils（p〈0.01）.It is very necessary to focus on the potential risk of heavy metals for food safety and human health in agricultural soils and vegetables in the midstream and downstream of the Xiangjiang River,Hunan Province of China.     

呼和浩特—包头盆地震源应力场状态分析

为了分析呼和浩特—包头盆地现今应力场状态,基于内蒙古地震台网记录的地震波形资料,运用振幅比方法获取2000—2016年该盆地及周边M_L≥2.7地震的震源机制解,计算其一致性参数,并反演区域应力场。结果表明,震源机制解特征主要表现为走滑特征,一致性参数空间分布处于低值状态,力轴方位基本与该区的应力场背景特征相符,即主压应力方位为北东、张应力方位为北西。     

二郎山公路隧道轴线地应力测试研究

介绍了二郎山公路隧道轴线上3个钻孔的地应力测试结果,应用水压致裂法在钻孔中测试,所测的两个不同大小的水平主应力都大于垂直主应力（除了地表以下很浅处外）,这个地应力与区域大地构造方向一致,在此基础上评价了隧道碉室围岩的稳定性。     

煤炭采空区处理的新方法与实例分析

位于乌鲁木齐市南湖路以西的煤炭采空区面积达67 100.5m^2,区内构造从南到北主要由八道湾向斜和七道湾背斜组成,地层产状变化不大。该矿区开采较深,且采空区塌陷区有明显的地下水活动迹象。在对深孔大体积采空区注浆时,比较各种常见注浆治理方法,均存在不同的制约因素,故决定采用灌浆爆破压密法对采空区进行压实加固。经现场爆破试验,该区重复爆破次数在3～5次左右。灌浆爆破压密处理后,对不同土层进行取样对比分析,得到其相应密度（增加）及空隙比（减少）的变化分别为：杂填土14.1%,-7.9%;素填土5.9%,-3.3%;塌落煤层7.8%,-7.7%。根据压缩数据及现场测量,处理后的土体沉降2～4m,部分空体地段的沉降量达10～20m,治理效果明显。     

Distinct quasi-biweekly features of the subtropical East Asian monsoon during early and late summers

Using Global Precipitation Climatology Project daily rainfall and ERA interim reanalysis data, we investigate the distinct characteristic of quasi-biweekly variation (QBV: 12–20 days) over East Asia (EA) during early (June 10–July 20) and late (July 21–August 31) summer. The QBV maximum variance is found over the core region of EA (30°–40°N, 110°–130°E), which includes eastern China (lower reaches of the Yellow, Huaihe, and Yangtze rivers) and the Korean Peninsula. At both its peak wet and dry phases, QBV over the core region has a baroclinic structure, but with different spatial distributions, different lower-level prevalent wind anomalies, and different upper-level major circulation anomalies in the two subseasons. Meanwhile, the two subseasons have different propagating tracks prior to reaching the peak phase, and different precursors associated with the local genesis of QBV. Furthermore, during the transition from the peak dry to peak wet phase of QBV, the major monsoon circulations have different behaviors that tropical monsoon trough extends eastward in early summer but retreats westward in late summer and the South Asia high (SAH) and western North Pacific (WNP) subtropical high move toward (away from) each other in early (late) summer. The abrupt change of mean state in mid to late July, which includes the northward migration of westerly jet, SAH and WNP, and the weakening and broken of westerly jet, is considered the root cause of the change in behavior of QBV. Finally, we indicate that the tropical monsoon trough and midlatitude westerly jet are possible sources of QBV over subtropical EA in both subseasons and provide useful guidance for 2–3 week predictions over EA.     

华北黄淮等地出现干旱南方强对流天气频繁——2007年5月——

5月,全国平均气温为17.1℃,比常年同期偏高1.5℃,为1951年以来同期最高值,其中上海、江苏、安徽、河南、湖北、湖南、陕西、甘肃、青海、宁夏区域平均气温均为历史同期最高值.全国平均降水量为59.7mm,较常年同期（67.0mm）略偏少.上中旬,西北东部、华北、黄淮温高雨少,干旱严重,下旬出现有效降水,旱情得到缓解.部分地区遭受暴雨或雷雨大风、冰雹等强对流天气袭击.北方地区出现6次沙尘天气过程,较2000-2006年同期偏多.下旬,华北、黄淮出现今年以来范围最大的一次高温天气.     

利用雷达资料反演方法对北京地区一次强对流天气过程的分析

利用多普勒雷达变分分析系统(VDRAS),对2006年8月1日傍晚北京城区出现的一次强对流天气过程(伴有冰雹、大风及强降水)的三维风场、温度场进行了初步分析.结果表明:(1)初始对流生成于北京西北部山区的河北省境内,系统过山移进北京城区时,受局地的动力及热力条件作用,迅速组织并强烈发展,形成带状的MCS即飑线;(2)在飑线生成之前,北京城区及东南部边界层低层存在较强的东风气流,并迅速扩展向西北方向延伸,与过山的西北偏北气流形成强的边界层辐合线.该近地面辐合线是飑线生成的主要触发机制,而边界层低层东风的加强和减弱以及北进和南退对辐合线的维持、飑线的生成、发展和减弱都起着重要的作用;(3)在边界层辐合线的作用下,不断有新生对流系统发展;(4)对流系统在整个发展过程中呈明显的带状分布特征,是一次典型的飑线过程,并伴有明显的阵风锋.     

气候变化对四川省主要农作物典型生育期的影响

采用气候倾向率和线性趋势法分析了四川省农业气候资源特征以及主要农作物典型生育期变化趋势。结果表明,1961—2014年全省大部地区≥10℃初日呈现提前趋势、终日呈推迟趋势,≥10℃积温呈升高趋势。在此背景下,玉米和水稻出苗期呈提前趋势,速率分别为6.6d/10a和3.5d/10a;玉米成熟期无明显变化趋势,水稻成熟期呈现明显推迟趋势,变化速率为2.4d/10a;玉米和水稻生育期天数均呈现了不同程度的延长。冬小麦出苗期无明显变化,而成熟期呈现提前趋势,速率达2.7d/10a,生育期天数呈现显著缩短趋势,速率达4.9d/10a。总体而言,积温的增加、温度生长期天数的延长为生育期长的作物品种种植提供了必要条件,通过品种的选择和播期调整,可以充分发挥资源优势,趋利避害,从而提高农作物产量。     

APN技术在地震前兆观测系统中的应用

介绍基于GPRS的APN无线网络通讯技术,并应用于地震前兆观测系统。实际运行结果表明,应用该技术系统可提高数据传输的稳定性、可靠性、安全性和实时性,是地震前兆观测数据传输的有效通讯手段。