Refining the understanding of the mineral system using deep geoelectrical data     

Lanfang He  Xuefeng Zhao  Xiaolu Xu  Rujun Chen  Hongchun Yao 《《地质学报》英文版》2018,92(Z1):295-297

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基于Pasternak双参数地基模型的陡坡段桥梁基桩内力计算方法          下载免费PDF全文

赵明华  彭文哲  杨超炜  肖尧 《水文地质工程地质》2018,(1):52-59

为考虑土体剪切模量对陡坡段桥梁基桩内力计算的影响,首先探讨桩后土压力的分布形式,并根据陡坡段桥梁基桩的承载特性建立简化分析模型;其次,引入Pasternak双参数模型,建立可考虑土体剪切模量的地基抗力计算模型;并在此基础上分别对受荷段与嵌固段基桩微元进行受力分析,求得各段控制差分方程,从而进一步迭代求解桩身位移及内力;最后,分别用陡坡段桥梁基桩实测数据与Pasternak双参数模型算例对本文内力计算方法进行验算,结果表明:本文计算方法用于陡坡段桥梁基桩内力计算是合理的,可为同类工程提供参考。  相似文献   

山东黄金西岭勘查区深部勘探孔防斜与纠斜措施          下载免费PDF全文

潘垚 《探矿工程》2018,45(3):37-41

西岭勘查区金矿找矿工作已全面进入勘探阶段,勘查区网度为80 m×80 m,对于钻孔质量要求十分严格：终孔靶点偏差不超过勘探网度的四分之一,即不超过20 m。对于西岭勘查区设计孔深均超过1500 m（部分钻孔设计甚至超过2500 m）的钻孔而言,这种要求远远超过地质岩心钻探规程要求。山东黄金地勘公司根据多年深孔施工经验,在防斜与纠斜方面均取得了一些突破,自主研发了钻具扶正器、独创了钻孔纠斜法,形成了一套实用的钻孔质量保证措施。  相似文献   

The Fragmentation in a Protoplanetary Disk and the Properties of the Resultant Self-Gravitating Clumps     

Chunjian Liu  Zhen Yao  Lianhua Tian 《Astronomy Reports》2018,62(11):713-723

We study the fragmentation properties in the protoplanetary disk and properties of the resultant self-gravitating clumps using our newly constructed disk model. Our disk model includes the mass inflall term from a molecular cloud core and the photoevaporation winds effect. We adopt the conventional fragmentation criterion to judge whether a protoplanetary disk can fragment. In this work, we follow our previous work to investigate the properties of the resultant self-gravitating clumps. In our calculation, the initial masses of the resultant self-gravitating clumps lie in the range of tens of M_J to more than one hundred of M_J, where M_J is the Jupiter mass. These initial masses can seemingly account for the masses of extrasolar planets in magnitude. We also calculate the subsequent gas accretion of clumps in 1.27 × 10⁴ yr after the formation of self-gravitating clumps. We find that the subsequent gas accretion of self-gravitating clumps is very efficient, and the clump masses grow to hundreds of M_J and the physical radii R_c of clumps increase to about 10 AU. Additionally, we also calculate the orbital migration of clumps. We find that most clumps have short migration timescale to be accreted onto the protostar, and only a small fraction of clumps have long migration timescale (>10⁶ yr) to successfully become gas giant planets. These results are consistent with previous studies.  相似文献   

Characterizing groundwater/surface-water interactions in the interior of Jianghan Plain,central China     

Du  Yao  Ma  Teng  Deng  Yamin  Shen  Shuai  Lu  Zongjie 《Hydrogeology Journal》2018,26(4):1047-1059

Hydrogeology Journal - Quantifying groundwater/surface-water interactions is essential for managing water resources and revealing contaminant fate. There has been little concern on the exchange...  相似文献   

Correlation analysis between drought indices and terrestrial water storage from 2002 to 2015 in China     

Yajie Zhang  Yao Li  Jing Ge  Gaopeng Li  Zhisheng Yu  Haishan Niu 《Environmental Earth Sciences》2018,77(12):462

Drought monitoring is a key topic in environmental monitoring and assessment although there is still a need to determine the correlation between drought monitoring indices and remote sensing products. We analyzed the correlation between the self-calibrating Palmer Drought Severity Index (sc_PDSI), the Standardized Precipitation Index and the Standardized Precipitation Evapotranspiration Index (SPEI) and terrestrial water storage monitored through the Gravity Recovery and Climate Experiment (GRACE) on a monthly timescale from 2002 to 2015 in China. As a consequence of anomalies in the soil water budget, the highly significant correlation between the sc_PDSI and the GRACE satellite-observed terrestrial water storage suggested that these two datasets are the most suitable for use in monitoring droughts. In comparing the three drought indices, the sc_PDSI was introduced as a means of drought monitoring in the Yangtze, Pearl, Huaihe, Southeast and Songhua River Basins, whereas the SPEI was found to be more applicable to other major river basins, such as the Inland River Basin. These diverse spatial behaviors are caused by the differences between the hydrological droughts characterized by these three drought indices.  相似文献   

The influence of the Three Gorges Reservoir regulation on a typical tributary heat budget     

Yao Cheng  Yuchun Wang  Huaidong Zhou  Chenghua Dang 《Environmental Earth Sciences》2018,77(22):764

Reservoir regulation and local climate both affect the heat budget of tributary bay. It is difficult for traditional methods to identify the influence of different factors on heat budget quantitatively. In this paper, for analysis of the control mechanisms of the heat budget of a large reservoir tributary, the water temperature distribution, and heat budget processes of the Meixi River, a typical tributary to the Three Gorges Reservoir was measured, and a new method was used to calculate the heat content composition of the tributary bay and identify the key factor of the heat balance. The result shows significant variation in the spatial and temporal distributions of water temperatures in the Meixi River, ranging from 12.4 to 28.9 °C on the surface and 12.0 to 24.4 °C at the bottom. The total heat exchange across the air–water interface that ranges from 0.1 to 6% of the budget is not the primary control factor of the annual tributary heat budget. Rather, the change in water depth produced by regulation of the Three Gorges Reservoir is the primary control factor of the tributary heat budget in the whole year, which ranges from 72 to 99% of the budget. The water temperature difference between the main stream and tributary is the not key factor of the heat budget, which ranges from 0.1 to 28% of the heat budget.  相似文献   

Soil wettability in ground engineering: fundamentals,methods, and applications     

S. D. N. Lourenço  Y. Saulick  S. Zheng  H. Kang  D. Liu  H. Lin  T. Yao 《Acta Geotechnica》2018,13(1):1-14

Wettability is a fundamental property controlling the extent of wetting in flat and granular solids. In natural soils, wettability affects a wide variety of processes including infiltration, preferential flow and surface runoff. In mineral processing, wettability is paramount in enhancing the efficiency of separation of minerals from gangue. The manipulation of surface wettability is equally crucial in many industrial applications. For instance, superhydrophobic surfaces are those on which water drops roll off easily and as such are used for self-cleaning applications. Therefore, while wettability is strongly cross-disciplinary, its evolution has been discipline-specific with a direct extrapolation or transfer of concepts, approaches, and methods to ground engineering unlikely to remain valid. This paper synthesizes relevant aspects from surface chemistry, materials science, mining engineering, and soil science, and discusses their implications within the context of new granular materials that resist wetting, for use in barriers or ground improvement and, in unsaturated soils, where the effects of wettability have been documented.  相似文献   

A New Computational Model of High-Order Stochastic Simulation Based on Spatial Legendre Moments     

Lingqing Yao  Roussos Dimitrakopoulos  Michel Gamache 《Mathematical Geosciences》2018,50(8):929-960

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蚌埠隆起老山片麻状二长花岗岩的成岩与变质特征及其地质意义   总被引：1，自引：0，他引：1  

陈洁  汪相  王耀 《地质论评》2018,64(5):1141-1166

蚌埠隆起是华北地块上中生代地质研究的一个十分难得的地质单元,它映现了中国东部最重要的两次构造运动(印支运动和燕山运动)所引起的岩浆作用和变质作用,其中,老山片麻状二长花岗岩就是一个代表性产物。该花岗岩的岩相学、地球化学以及锆石学的系统研究显示,它具有两个不同的岩石学特征:①它的斜长石斑晶的牌号(An_(14～18))、相对低硅高钙的主量元素、富Ba、Sr和贫Rb及无Eu负异常的微量元素等特征,以及它所含的岩浆锆石({211}锥面发育、较强的CL亮度及韵律环带构造、包含残核、正常的Hf含量)的U-Pb年龄(223.1 Ma)和ε_(Hf)(t)值(平均值为-14.2),表明它应该是印支运动的同造山花岗岩;②它的片麻状构造(斑晶矿物压扁拉长、各种交代—熔蚀结构)和变质结晶锆石({101}锥面发育、较弱的CL亮度、较高的Hf含量)的U-Pb年龄(156.2 Ma)和ε_(Hf)(t)值(平均值为-17.8),说明它在燕山运动中遭受了同造山变质作用。因此,老山片麻状二长花岗岩的存在,一方面使得大别造山带作为印支期陆陆碰撞造山带的岩石学记录完整,同时也制约了华南与华北两大板块之间碰撞挤压作用峰期的准确时间;另一方面,对燕山运动的起始时间(约170 Ma左右)和挤压高峰出现的时间(155±3 Ma)作出了合理的推断。这两方面的研究结果对于深入了解中国东部中生代的构造演化、岩石类型、成矿作用的现象及其机制具有深远的意义。  相似文献