Timoshenko beam solution for the response of existing tunnels because of tunneling underneath

An analytical solution for the deflection and internal forces of an existing tunnel because of tunneling underneath is presented. The existing tunnel is modeled as a Timoshenko beam resting on a Winkler foundation, which takes into account the contribution of shear deformation to the total deflection of the existing tunnel. The validity of the analytical solution is verified by a centrifuge test, and the merit of this analytical method is confirmed by comparison with the conventional Euler–Bernoulli beam model. Influential factors on the behavior of the existing tunnel are investigated by consideration of the variations of subgrade modulus, ground loss induced by the new tunnel construction, vertical clearance between the new tunnel and the existing tunnel, and relative existing tunnel–soil stiffness. Results show that the proposed analytical method is a valid and effective method to evaluate shearing‐induced deformation in existing tunnels with large diameters. Results also show that the pattern and the amplitude of the response of the existing tunnel are affected largely by ground loss induced by the new tunnel construction, vertical clearance between the new tunnel and the existing tunnel, and relative existing tunnel–soil stiffness. Copyright © 2015 John Wiley & Sons, Ltd.     

南海西沙西科1井层序地层格架与礁生长单元特征

碳酸盐岩礁滩体系是南海海域重要的油气储层之一.南海西沙岛屿全取心的科学钻井——西科1井, 为南海碳酸盐岩礁滩体系的详细研究提供极好的条件.通过西科1井岩心的宏观描述及微观分析, 结合高分辨岩心扫描及大量分析测试结果, 对碳酸盐岩礁滩体系展开了精细研究.根据识别出的6个暴露面、2个淹没面, 将西科1井中中新世以来划分为9个三级层序.其中晚中新世黄流组和第四系乐东组为主要成礁期, 以海泛面和暴露面为标志, 将礁体归纳为淹没型生长单元和暴露型生长单元两大类, 暴露型又进一步细分为硬基底和软基底两类, 淹没型可细分为快速淹没和缓慢淹没两类.垂向上形成了极具特色的礁体组合, 即慢步礁(或淹没礁)、同步礁(加积礁)、快步礁(暴露礁).研究成果对于南海生物礁生长过程及碳酸盐岩礁滩储层勘探具有重要参考价值.      

航空高光谱探测技术在准噶尔盆地东部地区油气调查中的应用

赋存于地下的油气藏(田)一般都存在向地表微渗漏,油气藏上方烃类垂向微渗漏可引起近地表物质的物理与化学性质变化,形成地物反射光谱特征异常,这为航空高光谱技术用于探测烃类微渗漏信息成为可能,成为油气选区调查和寻找油气的有效技术方法。在准东2500 km2范围内开展航空高光谱油气探测技术研究,获取了研究区CASI/SASI/TASI航空高光谱遥感数据,提取了与油气及与油气相关的粘土、碳酸盐、二价铁等信息,通过与已发现的油气藏(田)高光谱油气异常信息的对比研究,在准东地区落实了柳树河子和三台镇2个油气有利区。     

紫外分光光度法测定秋水仙碱中毒血清的临床应用

目的：探讨紫外分光光度法测定秋水仙碱中毒血清,为临床秋水仙碱中毒提供诊疗依据。方法取0．5 mL 血清加提取液（三氯甲烷∶甲醇＝95∶5）4．0 mL。充分震荡萃取,高速离心,取有机层于另一试管中氮气吹干,取0．2 mL 甲醇溶解残渣,混匀,取50 mL 做紫外扫描。结果血清中秋水仙碱最大吸收峰（351±1）nm,浓度在5．0～40μg／mL 范围内呈线性,回归方程Y ＝0．0502X ＋0．0013,其相关系数为0．9995,回收率为83．8％～102．8％,相对标准差为3．3％～4．8％。日内、日间相对标准差分别为3．22％～4．74％和3．45％～4．66％,最低检出浓度为1．0μg／mL。结论该方法操作简便,分析快速,结果准确,为临床诊断秋水仙碱中毒提供了一个简便准确的检测方法。     

The Confirmation of the Neoproterozoic Langshan Group in Inner Mongolia and Its Significance

<正>There is a large Mesoproterozoic rift at the northern margin of North China Craton(NCC),and one of China’s most important metallogenic belts,the Langshan-Zhaertai Shan-Bayan Obo mesoproterozoic metallogenic belt is just located in this rift.This metallogenic belt contains some large or ultra-large ore deposits,such as the Bayan Obo iron deposits and ultra-large rare earth deposits,and the large Dongshengmiao Cu-Pb-Zn sulphide deposits.The Zhaertai Group is composed of a set of metamorphic rocks,interbedded with thin ferruginous     

Evidence for the role of KIF17 in fish spermatid reshaping: expression pattern of KIF17 in Larimichthys polyactis spermiogenesis

Journal of Oceanology and Limnology - The homodimeric kinesin-2 protein KIF17 functions in intracellular transport and spermiogenesis in mammals. However, its role in fish spermiogenesis has not...     

Genomic analysis of a pure culture of magnetotactic bacterium Terasakiella sp. SH-1

Journal of Oceanology and Limnology - Magnetotactic bacteria(MTB) display magnetotaxis ability because of biomineralization of intracellular nanometer-sized, membrane-bound organelles termed...     

基于改进RANSAC算法的复杂建筑物屋顶点云分割

屋顶模型重建影响到建筑物完整模型重建质量,屋顶面点云分割质量对屋顶模型重建具有重要意义。针对传统RANSAC算法在屋顶点云面片分割时易产生错分割、过分割等问题,本文顾及点云位置信息,提出一种对点云重新分配的改进RANSAC点云分割算法。算法暂时剔除非平面内点,选取平面内点集中3个点作为初始样本,平面拟合判定邻域是否有效,从有效邻域中选取标准差值最小的3个点为初始模型。利用RANSAC算法对屋顶点云进行分割。利用K近邻算法统计误分类点与面片的距离降低误分类,优化过分割面片并进行连通性分析,利用距离及法向量一致性检验的方法重分配非平面内点。为验证本文算法有效性,选取芬兰Helsinki地区的3栋相互独立的复杂建筑物屋顶以及上海某小区的6栋建筑物群屋顶作为实验数据。在2组数据中,本文提出的改进RANSAC算法分割屋顶面片的平均准确率分别为92.17%、87.82%,78%的建筑物屋顶不存在过分割。在第2组数据中,所有分割面片上的点与其对应的最佳拟合平面的距离的标准差的平均值为0.030 m。实验结果表明,本文算法分割建筑物屋顶面片的准确率较高,较好的抑制了过分割现象,且抗噪能力强。