One-dimensional consolidation of soil under multistage load based on continuous drainage boundary     

Yi--> Tian  Wenbing Wu  Guosheng Jiang  M. Hesham El Naggar  Guoxiong Mei  Meijuan Xu  Rongzhu Liang 《国际地质力学数值与分析法杂志》2020,44(8):1170-1183

In engineering practice, a rapid loading rate can result in ground failure when the strength of soft soils is relatively low, and a multistage loading scheme is always utilized to deal with this situation. Firstly, under a multistage load and the continuous drainage boundary, an analytical solution of excess pore-water pressure and consolidation degree is obtained by virtue of the superposition formula of excess pore-water pressure, and a more general continuous drainage boundary under arbitrary time-dependent load is developed. Then, a comparison with existing analytical solutions is conducted to verify the present solution. A preliminary attempt on applying the continuous drainage boundary into the finite element model is made, and the feasibility of the numerical model for the one-dimensional consolidation under the continuous drainage boundary is verified by comparing the results calculated by FEM with that from present analytical solution. Finally, the consolidation behavior of soil is investigated in detail for different int erface parameters or loading scheme. The results show that, in land reclamation projects, a horizontal drain should be placed close to the boundary with a smaller interface parameter to improve the consolidation efficiency. The degree of consolidation is also related to the applied time-dependent load and interface parameters.  相似文献   

Short-term variability in the dates of the Indian monsoon onset and retreat on the southern and northern slopes of the central Himalayas as determined by precipitation stable isotopes     

Wusheng Yu  Tandong Yao  Lide Tian  Yaoming Ma  Rong Wen  Lochan P. Devkota  Weicai Wang  Dongmei Qu  Tek B. Chhetri 《Climate Dynamics》2016,46(1-2):159-176

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Shallowness of tropical low clouds as a predictor of climate models’ response to warming     

Florent Brient  Tapio Schneider  Zhihong Tan  Sandrine Bony  Xin Qu  Alex Hall 《Climate Dynamics》2016,47(1-2):433-449

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低空航测的系统工程问题分析     

田慧  林宗坚  文曲 《北京测绘》2016,(1)

当前低空航测工程实践中的许多技术问题,仅靠个别研究是不够的,必须运用系统工程学的方法进行研究。低空航测系统由飞行平台、成像传感器和航测处理等技术部分构成,各部分间存在相互关联、相互制约的关系,必须进行系统分析和系统优化的研究。同时,系统还受外部环境的制约,必须研究如何在不可改变的外部制约条件下,优化系统,达到系统目标的方法。  相似文献   

结合多尺度纹理特征的遥感影像面向对象分类     

林雪  彭道黎  黄国胜  王雪军 《测绘工程》2016,25(7):22-27

地物具有多尺度的特点,单一尺度难以准确描述遥感影像包含的地物纹理信息。利用我国自行研发的高分一号遥感影像数据,采用灰度共生矩阵对第一主成分进行纹理特征提取,利用Jeffries-Matusit距离选择多尺度组合,并通过单一纹理结合多光谱数据的分类精度,以及纹理特征间的相关性,最终选择多尺度纹理特征组合进行面向对象分类。研究结果表明:结合多尺度纹理特征组合的面向对象GF-1影像分类能有效提取地物信息,总体分类精度达到81.75%,Kappa系数0.78。  相似文献   

Strength Behavior of Shanghai Clayey Soil Reinforced with Wheat Straw Fibers     

Jili Qu  Zhongming Sun 《Geotechnical and Geological Engineering》2016,34(2):515-527

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   

Tin partition behavior and implications for the Furong tin ore formation associated with peralkaline intrusive granite in Hunan Province,China     

Xiaoyan Hu  Xianwu Bi  Ruizhong Hu  Guosheng Cai  Youwei Chen 《中国地球化学学报》2016,35(2):138-147

Tin deposits are often closely associated with granitic intrusions. In this study, we analyzed tin partition coefficients between different fluids and melts (\({\text{D}}_{Sn}^{aq.fl./melt}\)) as well as various crystals and melts \({\text{D}}_{Sn}^{aq.fl./melt}\)(\({\text{D}}_{Sn}^{crystal/melt}\)) from the Furong tin deposit associated with the Qitianling A-type granite. Our experimental results indicate that tin partition behavior is affected by the chemical compositions of fluids, melts, and minerals. Tin is prone to partitioning into the residual magma in fractional crystallization or other differential magmatic processes if the magma originated from crustal sources with high alkali content, high volatile content, and low oxygen fugacity. Highly evolved residual peralkaline granitic magma enriched in tin can lead to tin mineralization in a later stage. Furthermore, the volatiles F and Cl in the magma play important roles in tin partitioning behavior. Low F contents in the melt phase and high Cl content in the aqueous fluid phase are favorable factors for tin partitioning in the aqueous fluid phase. High Cl content in the aqueous fluid catalyzes water–rock interaction and leads to the extraction of tin from tin-bearing minerals. All these findings support a hydrothermal origin for the tin deposits. In light of the geotectonic setting, petrochemical characteristics, and mineralizing physicochemical conditions of the Furong tin deposit, it is inferred that the ore-forming fluid of the Furong tin ore deposit could have derived from the Qitianling peralkaline intrusion.  相似文献   

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

Zhen Liu  Hengliang Qu  Hongda Shi  Gexing Hu  Beom-Soo Hyun 《中国海洋大学学报(英文版)》2016,15(6):977-986

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.  相似文献   

Impacts of agricultural water saving practice on regional groundwater and water consumption in an arid region with shallow groundwater   总被引：1，自引：0，他引：1  

Hang Chen  Zhongyi Liu  Zailin Huo  Zhongyi Qu  Yuhong Xia  Alexander Fernald 《Environmental Earth Sciences》2016,75(16):1204

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内蒙古白乃庙逆冲推覆构造特征及其地质意义   总被引：1，自引：0，他引：1  

周志广  张达  谷永昌  王果胜  李红英  於炀森  柳长峰  刘文灿 《大地构造与成矿学》2018,(1):1-17

白乃庙逆冲推覆构造自四子王旗北东的十二台向东经白乃庙、博日和延至化德地区,大致沿北纬42°线东西向延伸超过190 km。它发育于华北克拉通与其北侧的奥陶纪白乃庙岛弧带之间,成为华北克拉通与北缘增生带的构造界线,是一套较为典型的陆缘褶冲带。它表现为华北克拉通北缘的中-新元古界白云鄂博群向北逆冲于白乃庙群及其弧后盆地的上志留统徐尼乌苏组和顶志留统西别河组之上。根据构造变形解析并结合音频大地电磁测深资料(CSAMT),得出白乃庙逆冲推覆构造由一系列分支逆断层组成,并向深部于120~800 m处交汇成主底板断层,构成一套叠瓦式逆冲推覆构造,并发育规模不同的构造窗和飞来峰。根据构造窗与飞来峰之间的距离,提出逆冲位移量大于14 km。通过线理及褶皱枢纽统计,指出白乃庙逆冲推覆构造的逆冲方向为自南向北。依据逆冲岩席中发育的断夹块的叠置关系及构造岩的特征,认为其经历了两个期次的活动。对断裂带内同构造形成的包裹石英透镜体的白云母分别进行了Rb-Sr和Ar-Ar同位素测年,认为白乃庙逆冲推覆构造早期活动于450~410 Ma,是白乃庙岛弧带与华北板块碰撞的构造反映。白乃庙逆冲断层晚期活动于晚二叠世至早三叠世,是古亚洲洋最终闭合的构造表现,亦印证研究区经历了印支期构造运动。  相似文献