Strength Behavior of Shanghai Clayey Soil Reinforced with Wheat Straw Fibers

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.     

Application of 2D numerical model to unsteady performance evaluation of vertical-axis tidal current turbine

Tidal current energy is renewable and sustainable, which is a promising alternative energy resource for the future electricity supply. The straight-bladed vertical-axis turbine is regarded as a useful tool to capture the tidal current energy especially under low-speed conditions. A 2D unsteady numerical model based on Ansys-Fluent 12.0 is established to conduct the numerical simulation, which is validated by the corresponding experimental data. For the unsteady calculations, the SST model, 2×10~5 and 0.01 s are selected as the proper turbulence model, mesh number, and time step, respectively. Detailed contours of the velocity distributions around the rotor blade foils have been provided for a flow field analysis. The tip speed ratio(TSR) determines the azimuth angle of the appearance of the torque peak, which occurs once for a blade in a single revolution. It is also found that simply increasing the incident flow velocity could not improve the turbine performance accordingly. The peaks of the averaged power and torque coefficients appear at TSRs of 2.1 and 1.8, respectively. Furthermore, several shapes of the duct augmentation are proposed to improve the turbine performance by contracting the flow path gradually from the open mouth of the duct to the rotor. The duct augmentation can significantly enhance the power and torque output. Furthermore, the elliptic shape enables the best performance of the turbine. The numerical results prove the capability of the present 2D model for the unsteady hydrodynamics and an operating performance analysis of the vertical tidal stream turbine.     

基于FY 3D的MERSI全球晴空数据合成技术

FY-3D极轨气象卫星作为最新一代的极地轨道气象卫星,其图像数据包含了丰富的植被、河流、山区等地表信息,对陆地资源调查、地表类型变化监测等具有重要作用。但几乎每轨遥感图像大约有2/3区域都被云雾覆盖,无法直接获取云层下的地表信息用于产品应用。本文研究晴空数据合成技术,首次提出反射率最小合成法、植被指数最大合成法和西格玛合成法的3个标准联合运用的晴空合成技术,利用先进的多时次气象卫星遥感数据合成技术,自动生成FY-3D中分辨率光谱成像仪(MERSI-II)250m分辨率晴空遥感数据,较好地实现了云和云阴影的去除,生成的晴空效果良好,具备了后续应用的价值。     

学习《矿山环境保护与综合治理方案编制规范》之体会

山东作为一个矿业大省,矿产资源种类多、分布广,开发利用程度高,为国民经济发展做出了突出贡献。但与此同时,所引发的地质灾害及环境地质问题越发凸显。2007年5月21日,国土资源部发布了《矿山环境保护与综合治理方案编制规范》（DZT／223—2007）（以下简称“规范”）。山东省国土资源厅在总结前期矿山地质环境影响评价工作经验基础上,以“鲁国土资发[2008]70号”下发《关于开展矿山地质环境保护与综合治理方案编制工作的通知》及附件《山东省矿山地质环境保护与综合治理方案编制管理办法（试行）》,     

3S技术在堰塞湖应急治理中的应用研究

以四川堰塞湖为例,首先阐述了3S技术的特点、项目实施基本指标和项目作业技术系统;其次重点叙述了3S技术在项目实施中的技术流程,包括资料收集、地形图矢量化、矢量数据空间分析、TM遥感影像处理、野外调查建立解译标志、遥感解译、土壤侵蚀强度计算、解译成果野外校核、数据库集成等步骤.最后列举了如何利用3S技术解决危情作出的贡献.