绕墙脚转动的挡土墙主动土压力分布研究

对挡土墙背离填土绕墙脚转动时墙后滑裂土体的应力状态进行了详细分析,建立了墙后滑裂体水平土层墙面反力、滑裂面反力、土层间剪力和土层竖向土压力强度之间的关系式。为了考虑挡土墙绕墙脚转动时墙脚局部土体并未达到极限状态,对墙面摩擦角、滑裂面土体的内摩擦角予以折减。在水平土层单元法的基础上,考虑水平土层间剪力作用、每一土层的墙面摩擦角和滑裂面水平倾角等的变化,建立了土层竖向土压力强度的逐层渐近的计算方法,并给出了挡土墙主动土压力强度、土压力合力及其作用位置的计算公式。经比较表明：挡土墙主动土压力分布曲线与试验结果基本一致,计算得的主动土压力系数与试验结果很接近,比库仑解大;计算得出的滑裂面为一曲面,其顶部开裂宽度比库仑滑裂面小,与工程实际相符。     

乌鲁木齐河流域不同水体中的氧稳定同位素

The variations of the stable oxygen isotope in different water mediums in Urumqi River Basin, China, are analyzed. The stable oxygen isotope in precipitation has marked temperature effect either under synoptic or seasonal scale at the head of Urumqi River. The linear regression equations of δ^18O against temperature are δ^18O=-0.94T-12.38 and δ^18O=1.29T-13.05 under the two time scales, respectively. The relatively large δ^18O/temperature slopes show the strong sensitivity of δ^18O in precipitation to temperature variation at the head of Urumqi River. According to the analyses on the δ^18O in precipitation sampled at three stations with different altitudes along Urumqi River, altitude effect is notable in the drainage basin. The δ^18O/altitude gradients have distinct differences: the gradient from Urumqi to Yuejinqiao is merely -0.054‰/hm, but -0.192‰/hm from Yuejinqiao to Daxigou, almost increasing by 2.6 times over the former. No altitude effect is found in surface firn the east branch of Glacier No. 1 at the head of Urumqi River, showing that precipitation in the glacier is from the cloud cluster with the same condensation level. Influenced by strong ablation and evaporation, the δ^18O in surface firn increases with increasing altitude sometimes. Survey has found that the δ^18O in meltwater at the terminus of Glacier No. 1 and in stream water at Total Control have the similar change trend with the former all smaller than the latter, which displays the different runoff recharges, and all mirror the regime of temperature in the same term basicallv.     

地区主导产业定量选择及优化调整研究——以济南市为例

本文建立了工业、第三产业和农业主导产业评价指标体系,提出了非线性功效函数定量评估模型,对济南市三类产业分行业进行了定量评价,确定了5个工业主导产业、6个第三产业主导产业和1个农业优势产业,提出了21世纪初期济南市产业结构调整优化重点     

胶莱盆地早白垩世莱阳群沉积物源及地质意义

应用古流向、砾石成分及砂岩碎屑锆石定年方法,综合分析了胶莱盆地早白垩世莱阳群沉积时期的物源组成及其地质意义。古流向,五莲—诸城显示较稳定的N向,莱阳—乳山一带由早期的E-SE向逐渐转变为晚期W-NW向。砾石成分,五莲—诸城—胶州地区以花岗片麻岩、花岗岩、大理岩和石英岩为主,莱阳—乳山早期花岗岩砾石成分含量高,晚期成分复杂。碎屑锆石年龄分布主要集中在110~145 Ma,150~180 Ma,200~250 Ma,600~950 Ma和1700~2600 Ma。由此推断胶莱盆地在早白垩世莱阳群沉积期的物源主要由三部分组成:1盆地南缘苏鲁造山带超高压-高压变质岩和浅变质杂岩;2盆地周缘燕山期(J2-3-K1)花岗岩;3北侧胶北隆起基底(亲华北型)变质岩。并且盆地物源组成表现出明显的区域差异性,这种差异说明当时苏鲁造山带的南、北段在抬升及抬升后可能存在着差异性的隆起和改造,表现为苏鲁造山带南段(南苏鲁造山带)隆升幅度大并且稳定,北段(北苏鲁造山带)表现出较为低缓的隆起或者局部的小隆起并且后期经历大规模的塌陷。另外,物源也指示早白垩世莱阳群沉积时期,胶莱盆地呈现出西高东低的古地貌特征,直到莱阳群沉积晚期,盆地东部才有所抬升。     

九华山地质资源与地域文化的渊源

九华山地质公园位于长江中下游南岸安徽省池州市。2019年4月17日,联合国教科文组织执行局第206次会议通过决议,正式批准九华山地质公园成为联合国教科文组织世界地质公园。批文显示,九华山地质公园,其名意为“九座壮丽的山峰”,面积139.7km2。其中的4个山顶上建有庄严的佛教寺庙,有些可远溯至公元5世纪。除了宗教、历史...     

SPATIAL DISTRIBUTION AND VARIATION TENDENCY OF DROUGHTS AND FLOODS IN HUNAN PROVINCE DURING THE PAST 36 YEARS

Using the 1970–2005 annual precipitation and evaporation data at 80 gauge stations across Hunan province, this work analyzes the spatial distribution and variation tendency of the local droughts and floods using linear regression, wavelet analysis, abrupt change, clusters, Empirical Orthogonal Function (EOF) and rotated EOF (REOF). Results show that there are four dry areas and three wet areas in Hunan. The whole province exhibits a moistening trend except some small areas in western, eastern and southern Hunan. The most prominent feature of annual precipitation is that the whole province basically displays a consistent variation tendency, as far as the dominant EOF mode is concerned. In addition, the spatial features of the other EOF modes include dry-wet differences, e.g. wet (or dry) in the north versus dry (or wet) in the south, wet (or dry) in the center and dry (or wet) in the surrounding areas. The distribution of the ratios of evaporation to precipitation exhibits both common features as well as spatial differences, which can be classified into four types: South Hunan, North Hunan, Northeast Hunan, and Central Hunan. There is an abrupt change from dry to wet patterns in the early 1990s. Generally, the drought-flood distribution presents variations of three periods. In the late 2000s, Hunan province will be in a period of drought, followed by a period of flood.     

热带大气季节内振荡对华南前汛期降水的影响

本文基于实时的热带大气季节内振荡(MJO)指数和中国台站降水资料,研究了MJO对中国华南前汛期(4～6月)降水的影响.结果表明,随着MJO的活跃中心从印度洋进入西太平洋,华南地区的降水由偏多转为偏少.最显著的降水正负异常分别位于第4位相和第7位相,其区域平均的最大正负异常值相对于气候平均值的变化约为17%和11%.与降...     

长江流域大气降水中δ^18O变化与水汽来源

根据GNIP所提供的长江流域多年月平均降水中δD、δ^18O料以及NOAA-CIRES提供的NCEP/NCAR再分析资料,研究了长江流域降水稳定同位素与降水量、水汽压、温度和水汽来源之间的关系。结果表明：在平均季节尺度下,长江流域大气降水中δ^18O降水量、水汽压和温度均存在显著的负相关关系,说明该流域降水中δ^18O...     

产于层间构造带中的新型萤石矿体地质特征——以浙江常山县高坞山矿段ⅩⅣ号矿体为例

浙江常山八面山萤石矿床是浙江省首次发现的新类型萤石矿床,其中高坞山矿段ⅩⅣ号矿体为矿田中受寒武系碳酸盐岩层间构造带控制的似层状矿体的典型代表.萤石矿体厚度大,品位较高,资源储量规模达中型.通过矿体地质特征和控矿因素的研究,认为矿床属低温热液成因,受岩浆岩、构造和地层因素的共同控制;成矿作用以充填作用为主,伴有交代作用;...