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Derivation of the work expression and discussion on the effective principle and the phase separation theorem in unsaturated soil

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Science china(Technological Sciences) 2008年第9期51卷 1530-1541页

作者： ZHAO ChengGang ZHANG XueDong school of civil engineering and architecture Beijing Jiaotong UniversityBeijing 100044China

Based on the balance equations for mass, linear momentum, energy in porous media theory and some hypotheses in unsaturated soil mechanics, an expression of the total deformation work W is derived, and with the help of the specific ex-pression of the work, the effective stress conjugated with the displacement of the soil skeleton is suggested by the authors, which has the similar form as the expressions proposed by Wheeler (2003) and some other researchers according to their experience and intuition, but the effective stress presented in this paper is derived on the basis of porous media theory and its assumptions, whose premise and hypothesis are clear. It is also pointed out that due to the complexity of the physical mechanism and various influencing factors, it is impossible in unsatu-rated soil mechanics to determine the deformation of solid skeleton by the effective stress only, like in the saturated soil mechanics. Besides, by using the expression of the deformation work and the free energy Aα for each phase, the applicability of the Phase Separation Principle proposed by Passman (1984) in unsaturated soil is discussed, and it is considered that the principle should not strictly apply to un-saturated soil mechanics.

关键词： total deformation work effective stress unsaturated soil Phase Separation Principle porous media theory

Performance Analysis of GPS at Three Ephemerides on Medium and Long Baselines

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Performance Analysis of GPS at Three Ephemerides on Medium a...

Constitutive modeling for unsaturated soils considering gas hardening effect

第十三届中国卫星导航年会

作者： Xiongwei Peng Xiaoxing He Xiaping Ma Dejun Wang Hui Jin College of Geomatics Xi'an University of Science and Technology school of civil and Surveying engineering Jiangxi University of Science and Technology school of civil architecture East China Jiaotong University school of civil and Transportation engineering Hebei University of Technology

With the continuous improvement and updating of GPS technologies, medium and long baselines are widely used in GPS data processing. Currently, the International GPS Geodynamic Service Center（IGS） provides the final precise ephemeris（IGSF）, rapid precise ephemeris（IGR） and ultrarapid precise ephemeris（IGU）. These three different precise ephemerides are different in terms of accuracy and update frequency, and have different effects on the accuracy of the baseline solution in practical applications. Therefore, in order to analyze the influence of the published accuracy of these three ephemerides on the results of the baseline solution. Based on 7-day observation files and their corresponding ephemeris files, this study uses Trimble Business Center（TBC） 5.2 software to perform the baseline solution with three different ephemeris files. We take the baseline result of the IGSF solution as the true value, and compare the baseline results of the other two ephemeris solutions. There are specific discussions about baseline length within 200 km, 500 km-1300 km and 1300 km-2600 km. Results show that when the baseline length is 1300 km-2600 km, the 7-day average of the difference of ΔX, ΔY and ΔZ of IGR-IGSF are all less than 1.19 mm, while IGU-IGSF are all less than 8.64 mm. In terms of root mean square, the 7-day average accuracy in the X, Y, and Z directions of the TBC equipped with IGSF is less than 11.76 mm, while the equipped IGU is less than 12. 94 mm. Therefore, in the solution of medium and long baselines, the final precise ephemeris and the rapid precise ephemeris have higher accuracy, and the ultrarapid precise ephemeris is less accurate. When the final precise ephemeris is not acquired in time, the fast precise ephemeris can be used for the baseline solution.

关键词： IGSF IGR IGU Medium and long baseline Root mean square

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Chinese Science Bulletin 2011年第16期56卷 1739-1745页

作者： LIU Yan ZHAO ChengGang CAI GuoQing HUANG Lu school of civil engineering Beijing Jiaotong University Beijing 100044 China school of civil engineering and architecture Southwest Petroleum University Chengdu 610500 China

The influence of gases on unsaturated soils is discussed in the paper.First,the selection of stress state variables is discussed.It is shown that gas pressure as well as generalized effective stress and modified suction are required to construct a constitutive model of an unsaturated soil.The deformation mechanisms of solid,liquid and gas phases in soils are then investigated.It is realized that the deformation of gas phase interacts with the deformations of the other two phases in soils.Gas laws are used to describe the gas behavior.Similar to the other two phases in soil,the change of gas volume can be divided into an elastic part and a plastic part, and the latter part is then introduced to the soil hardening equation to reflect the impact of the gas on the soil.Then,a simple elasto-plastic model considering the gas effect for isotropic states is developed.Finally,the model predictions are given and compared with existing experimental data.A good agreement between them is found.Comparisons of the predictions between our model and Wheeler’s model are also performed.

关键词：气体压力本构模型非饱和土硬化效应应力状态变量变形机制模型预测弹塑性模型

Two-sided Long Baseline Radargrammetry from Ascending Descending Orbits with Application to Mapping Post-seismic Topography in the West Sichuan Foreland Basin

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Journal of Mountain Science 2014年第5期11卷 1298-1307页

作者： CHENG Hai-qin CHEN Qiang LIU Guo-xiang YANG Ying-hui LIU Li-yao Department of Remote Sensing and Geoinformation engineering Southwest Jiaotong University school of civil engineering and architecture East China Jiaotong University

合成的孔雷达(SAR ) stereo-radargrammetry 的片面上升或下降限制了由于短空间基线(100 km ) 和小交叉角度的地志的印射的精确性。以便改进从卫星转菠的 SAR radargrammetry 产生数字举起模型(DEM ) 的表演和可靠性，从与长空间的基线(... 详细信息

合成的孔雷达(SAR ) stereo-radargrammetry 的片面上升或下降限制了由于短空间基线(100 km ) 和小交叉角度的地志的印射的精确性。以便改进从卫星转菠的 SAR radargrammetry 产生数字举起模型(DEM ) 的表演和可靠性，从与长空间的基线(1000 km ) 的几何配置登上并且下降轨道的联合的两方面的 stereo-radargrammetry 的探索在这研究被进行。在到放方程的地球表面和 Doppler 的 SAR 传感器之间的观点范围几何学被采用建立实体镜的交叉模型。两方面的 radargrammetric 举起的测量无常根据在输入 SAR 图象之间的同类的点的雷达视差被估计。ALOS/PALSAR (先进土地观察卫星 / 阶段数组类型 L 乐队合成的孔雷达) 的二立体声对有轨道的分离的获得在有在西南的中国卷地形学的西方四川低岬盆上的几乎 1080 km 在学习被采用在撞击了这个区域的 2008 Wenchuan 地震以后获得新地面数据。对两方面的 radargrammetric DEM 的量的精确性评价与参考被执行回答 GPS 观察。试验性的结果证明没有使用的地面控制点(GCP ) ，举起精确性到达 5.5 m，并且精确性是进一步的改善了到 1.5 m，一仅仅 GPS GCP 用作最少的限制。理论分析和严峻的结果证明从上升并且下降的轨道的两方面的长基线 SAR radargrammetry 能是为大区域、高的精确性的一种很有希望的技术选择地志的印射。

关键词：雷达摄影测量川西前陆盆地地形测绘长基线轨道双面合成孔径雷达数字高程模型

A SECOND-ORDER MOMENT TURBULENCE MODEL FOR POWER LAW FLUID WITH PARTICLES

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Journal of Hydrodynamics 2007年第5期19卷 607-612页

作者： ZENG Zhuo-xiong PAN Yang ZHONG Chun QIU Guo-bin Aeronautic and Mechanical engineering College Nanchang Hangkong University Nanchang 330063 China school of civil engineering and architecture East China Jiaotong University Nanchang 330013 China

The USM-θ model of power law fluid for dense two-phase turbulent flow was developed, which combines the unified second-order moment model for two-phase turbulence with the particle kinetic theory for the inter-particle collision. This model was used to simulate the turbulent flow of power law fluid single-phase in pipe. It is shown that the USM- θ model has better prediction result than the κf -κf - κ- εp -θ model. The USM-O model was then used to simulate the dense two-phase turbulent up flow of power law fluid with particles. With the increase of the flow exponent, the velocities of power law fluid and particles increase near the pipe centre. Comparison between the two-phase flow of power law fluid-particle and of liquid-particle indicates that the axial fluctuation velocity of fluid phase and particle phase in liquid-particle two-phase flow is smaller than that in the power law fluid two-phase flow, but the two-phase velocities of power law fluid-particle and liquid-particle are close to each other.

关键词： power law fluid two-phase flow second-ordermoment turbulence model

A natural manganese ore as a heterogeneous catalyst to effectively activate peroxymonosulfate to oxidize organic pollutants

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Chinese Chemical Letters 2022年第11期33卷 4792-4797页

作者： Jinchuan Gu Ping Yin Yi Chen Honglin Zhu Rui Wang school of Food and Bioengineering Civil Engineering and Architecture and EnvironmentEmergency ScienceXihua UniversityChengdu 610039China Sichuan Rongxinkai engineering Design Co. Ltd.Chengdu 610039China Faculty of Geosciences and Environmental engineering Southwest Jiaotong UniversityChengdu 611756China

Heterogeneous transition metal catalysts are indispensable in improving environmental pollution.However,their fabrication is often costly and cumbersome,and they can easily pollute the environment.This study proposed using a natural Gabonese ore(GBO)containing Mn_(x)O_(y) and FexOy as catalysts to degrade orange Ⅱ(OII)via peroxymonosulfate(PMS)activation.The GBO+PMS system exhibited extraordinarily high stability and catalytic activity towards OII elimination(92.2%,0.0453 min^(−1)).The reactive oxygen species(ROS)generated in the system were identified using radical scavenging tests and electron spin-resonance(ESR)analysis.Singlet oxygen(^(1)O_(2))represented the dominant reactive species for OII degradation,while the system presented a lower reaction energy barrier and was effective in a broad pH range(2-10).This work also proposed the activation mechanism for the GBO+PMS system and OII degradation pathways.This study revealed a new approach for exploring inexpensive,eco-friendly,efficient,and stable heterogeneous transition metal catalysts.

关键词： Transition metal Heterogeneous catalyst Natural ore OrangeⅡ Peroxymonosulfate

Effect of Coal Gangue with Different Kaolin Contents on Compressive Strength and Pore Size of Blended Cement Paste

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Journal of Wuhan university of Technology(Materials Science) 2008年第1期23卷 12-15页

作者：陈益民 ZHOU Shuagxi ZHANG Wensheng china Building Materials Academy Beijing 100024 China school of civil engineering and architecture East China Jiaotong University Nanchang 330013 China

The effects of activated coal gangue on compressive strength, porosity and pore size distribution of hardened cement pastes were investigated. Activated coal gangue with two different kaolin contents, one higher and one lower, were used to partially replace Portland cement at 0%, 10%, and 30% by weight. The water to binder ratio（w/b） of 0.5 was used for all the blended cement paste mixes. Experimental results indicate that the blended cement of activated coal gangue mortar with higher kaolin mineral content has a higher compressive strength than that with lower kaolin mineral content. The porosity and pore size of blended cement mortar were significantly affected by the replacement of activated coal gangue.

关键词： activated coal gangue compressive strength porosity blended cement paste

Application of Non-Detective Techniques in Traditional Masonry Structures

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Journal of Shanghai jiaotong university(Science) 2013年第3期18卷 306-310页

作者：程成车爱兰曹永康 school of Naval architecture Ocean and Civil Engineering Shanghai Jiaotong University

Study on the non-destructive detection techniques and damage identification method is of great importance in protecting and rehabilitating the ancient architectural structure. In order to identify the location and the grade of structural damages, a multi-point microtremor measurement is performed on carved brick screen walls at Songjiang area in Shanghai, and the observed dynamic parameters (natural frequencies and natural modal) are obtained. On the other hand, the dynamic parameters of the original structure are calculated by finite-element-method (FEM). Normalizing the observed and calculated parameters on unified physical quantity, the damages are located by the variation on vibration modal, and the grade of structural damages is quantitatively evaluated by stiffness losses based on the variation on vibration modal.

关键词： damage identification microtremor natural modal stiffness loss

Pore Structure of Cement Pastes Blended with Volcanic Rock

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Journal of the Chinese Ceramic Society 2016年第1期3卷 17-25页

作者： YU Lehua ZHOU Shuangxi LI Liling school of civil engineering East China Jiaotong University

The pore parameters of cement pastes blended with volcanic rock at the curing age of 1, 28 and 90 d were determined by a mercury intrusion porosimetry. The pore structure of the pastes was characterized through the analysis of porosity, average pore diameter, the most probable pore aperture, pore size distribution, as well as total pore volume. For the improvement of mechanical property and durability of cement-based material, the correlation of the formed pore structure with hydration time and replacement level of volcanic rock for cement was revealed. The results indicate that volcanic rock can diminish porosity and reduce pore size in cement paste when curing time prolongs, which is particularly prominent with replacement level of less than 20% in late period. The more harmful pores(i.e., capillary pore) are gradually transformed into harmless pore(i.e., gel pores or micropore), even fully filled and disappeared when hydration products increase. The pore structure of the cement paste is thus refined. The beneficial effect of volcanic rock on the pore structure of cement paste could enhance the mechanical property and durability of cement-based material.

关键词： cement volcanic rock paste pore diameter size