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1.
It is generally recognized that the low strength and high compressibility are the characteristics of soft soil. In addition to other techniques, reinforcement can also be used in increasing the strength and decreasing the deformation of this kind of soil. The results of an investigation into the effects of a natural fiber on the consolidation and shear strength behavior of Shanghai clayey soil reinforced with wheat straw fibers are presented in this paper. A series of one dimensional consolidation and triaxial tests were conducted on samples of unreinforced and reinforced Shanghai clayey soil with different percentages of randomly distributed wheat straw fibers. The results show that the preconsolidation pressure decreases and the coefficient of swelling and compression generally increase with increasing the fiber content until a optimum content value. Furthermore, the addition of wheat straw fiber leads to a significant increase in shear strength and friction angle of the natural soil and there is an optimum wheat fiber content that makes this increase maximal. 相似文献
2.
从岩体产出的地质背景、岩石学、岩石化学、稀土元素特征、岩石熔化实验,Sr~(87)/Sr~(86)初始比值等资料的初步研究,表明岩体成因属壳型(相当徐克勤的陆壳改造型)花岗岩。但由於岩浆近地同化混染白云质灰岩,致使造岩矿物黑云母富含镁质,又具有过渡型(相当徐克勤的同熔型)花岗岩的某些特点。而钨、铅、锌(银)多金属矿床与该岩体有着成因上的联系。 相似文献
3.
YAO Jili XU Yufei XIAO Wei 《地球空间信息科学学报》2007,10(3):173-176
Three transformation models (Bursa-Wolf, Molodensky, and WTUSM) are generally used between two data systems transformation. The linear models are used when the rotation angles are small; however, when the rotation angles get bigger, model errors will be produced. In this paper, we present a method with three main terms: ① the traditional rotation angles θ , φ ,ψ are substituted with a , b, c which are three re-spective values in the anti-symmetrical or Lodrigues matrix; ② directly and accurately calculating the formula of seven parameters in any value of rotation angles; and ③ a corresponding adjustment model is established. This method does not use the triangle function. Instead it uses addition, subtraction, multiplication and division, and the complexity of the equation is reduced, making the calculation easy and quick. 相似文献
4.
热带气旋是影响我国沿海的主要灾害性天气系统之一, 它产生的狂风、暴雨、巨浪和风暴潮, 给沿岸地区人民生命和国家财产安全带来严重威胁。而严重的台风灾害, 往往是台风登陆引起的。为进一步研究登陆热带气旋的活动规律, 总结了2005年登陆我国热带气旋的特点, 结果表明:2005年登陆我国热带气旋具有登陆季节短、登陆地点分布异常、台风比例异常偏高、灾害损失极为严重的特点。同时, 还讨论了2005年登陆我国热带气旋异常的气候原因, 并指出未来几年登陆热带气旋和台风的年频数处在上升趋势中。 相似文献
5.
西湖凹陷平北地区平湖组基于地震多属性的储层预测 总被引：1，自引：0，他引：1
始新统平湖组是东海西湖凹陷平北地区最重要的油气储层,但受资料条件的限制,应用常规方法无法进行精细的储层预测,制约了研究区的油气勘探部署和进程。应用地震多属性分析技术,结合测井曲线、岩心、岩性及区域地质资料,对平北地区平湖组的岩相进行了精细解释,并对有利目标区进行了初步预测,结果表明,平北地区平湖组发育潮汐控制的三角洲相和潮坪相两种类型的沉积相,并以三角洲相内的储层发育,砂体连片性好,工区西南部三角洲前缘相发育区为油气勘探的有利目标区。 相似文献
6.
中国区域发展和产业布局正迈向“以内循环为主体、内外循环相互促进”的新发展格局,而城市群肩负着内循环增长极、辐射源和双循环战略支点的双重使命。现有研究对核心城市群高科技产业带动内循环的空间格局及其政策启示的关注尚显薄弱。论文以改革开放以来深度融入外循环的粤港澳大湾区为例,刻画并对比其战略性支柱产业(电子信息、汽车、家电)和战略性新兴产业(生物科技、智能机器人、新材料)在区域内部和外部(带动粤东西北、泛珠三角、全国)的多尺度空间联系,总结推进以内循环为主体构建新发展格局的政策启示。研究发现：① 粤港澳大湾区高科技产业多尺度空间联系以经济发达地区之间为主,区域内形成以广深港科技创新走廊为主轴向周边辐射,国内形成以粤港澳大湾区、长三角、京津冀和成渝4大国家级城市群为菱形结构顶点、中西部省会城市为重要节点的空间格局;② 战略性支柱产业相比战略性新兴产业形成了更加稳固的菱形结构顶点支撑和城市区域化溢出及区域间联动进程,辐射带动的地理范围更广,在粤港澳大湾区内外的产业功能分工也更加完善;③ 建议以菱形结构作为内循环的基础空间架构,构建城市、区域、国家多尺度空间相互联动、经济发达地区和欠发达地区优势互补的多尺度嵌套和梯度循环并存的内循环空间格局。 相似文献
7.
Assimilating Best Track Minimum Sea Level Pressure Data Together with Doppler Radar Data Using an Ensemble Kalman Filter for Hurricane Ike (2008) at a Cloud-Resolving Resolution 
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下载免费PDF全文 Extending an earlier study, the best track minimum sea level pressure (MSLP) data are assimilated for landfalling Hurricane Ike (2008) using an ensemble Kalman filter (EnKF), in addition to data from two coastal ground-based Doppler radars, at a 4-km grid spacing. Treated as a sea level pressure observation, the MSLP assimilation by the EnKF enhances the hurricane warm core structure and results in a stronger and deeper analyzed vortex than that in the GFS (Global Forecast System) analysis; it also improves the subsequent 18-h hurricane intensity and track forecasts. With a 2-h total assimilation window length, the assimilation of MSLP data interpolated to 10-min intervals results in more balanced analyses with smaller subsequent forecast error growth and better intensity and track forecasts than when the data are assimilated every 60 minutes. Radar data are always assimilated at 10-min intervals. For both intensity and track forecasts, assimilating MSLP only outperforms assimilating radar reflectivity (Z) only. For intensity forecast, assimilating MSLP at 10-min intervals outperforms radar radial wind (Vr) data (assimilated at 10-min intervals), but assimilating MSLP at 60-min intervals fails to beat Vr data. For track forecast, MSLP assimilation has a slightly (noticeably) larger positive impact than Vr(Z) data. When Vr or Z is combined with MSLP, both intensity and track forecasts are improved more than the assimilation of individual observation type. When the total assimilation window length is reduced to 1h or less, the assimilation of MSLP alone even at 10-min intervals produces poorer 18-h intensity forecasts than assimilating Vr only, indicating that many assimilation cycles are needed to establish balanced analyses when MSLP data alone are assimilated; this is due to the very limited pieces of information that MSLP data provide. 相似文献
8.
不同国家或地区在不同的历史时期采用的是不同的坐标系,因此存在着国家坐标和地方坐标之间的坐标转换。为了综合利用测绘成果,工程坐标与国家坐标进行相互转换是必要的。基于高斯平面的工程坐标与国家坐标转换模型,广泛采用相似变换。通过选择不同的相似变换参数,提出无需列误差方程和法方程即能得到转换参数最小二乘解的重心化模型,并推导出... 相似文献
9.
气油比是已投入开发凝析气藏的一项重要开发指标。气油比的变化可反应气井、气藏生产状态,凝析气藏压力变化以及带水气藏边底水的推进程度。油藏工程研究人员还可据气油比变化对气井、气藏将来的生产形势做初步分析。因此,分析带水凝析气藏气油比变化规律以及对其影响因素进行深入剖析,对于凝析气藏生产具有重要的指导意义。 相似文献
10.
球形标靶的固定式扫描大点云自动定向方法 总被引：1，自引：0，他引：1
根据目前地面激光扫描数据获取速度快、数据量大、测量距离远、专用特殊材料制作的标靶识别距离近、点云定向数据处理相对滞后、自动化程度低、不能适应远距离地形测量的现状,提出了从大点云中(每站1亿点以上)自动探测远距离标靶的点云定向方法。该方法首先根据标靶控制点的工程测量坐标信息,搜索到标靶所在点云环,然后对各点云环进行扇形分区,快速探测标靶,获取标靶中心扫描坐标,最后平差计算扫描仪位置参数和姿态参数,实现点云坐标到工程测量坐标的转换。该方法在普通配置的计算机上得到实现,并成功用于远距离山区地形测量,其中定向标靶半径0.162m,标靶到扫描站距离在180~700m之间。 相似文献