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61.
62.
XiaoHui Chen 《International Journal of Solids and Structures》2013,50(20-21):3266-3273
This paper has extended modified mixture theory with consideration of hydration swelling in unsaturated rock. By using non-equilibrium thermodynamics and Biot elasticity, a fully coupled formulation including hydration swelling term is derived. Standard arguments of non-equilibrium thermodynamics are used to derive the Darcy’s law for unsaturated flow. Helmholtz free energy has been used to give the relationship between the stress and pore pressure. The chemical potential of water in pore space and clay platelets has been included in the analysis of water sensitive materials such as shale. Finally, a simple numerical example has been presented for illustrative purpose, the results show that the swelling parameter has a strong influence on stress and strain. 相似文献
63.
Laboratory-scale virus transport experiments were conducted in columns packed with sand under saturated and unsaturated conditions.
The viruses employed were the male-specific RNA coliphage, MS2, and the Salmonella typhimurium phage, PRD1. The mathematical model developed by Sim and Chrysikopoulos (Water Resour Res 36:173–179, 2000) that accounts
for processes responsible for removal of viruses during vertical transport in one-dimensional, unsaturated porous media was
used to fit the data collected from the laboratory experiments. The liquid to liquid–solid and liquid to air–liquid interface
mass transfer rate coefficients were shown to increase for both bacteriophage as saturation levels were reduced. The experimental
results indicate that even for unfavorable attachment conditions within a sand column (e.g., phosphate-buffered saline solution;
pH = 7.5; ionic strength = 2 mM), saturation levels can affect virus transport through porous media. 相似文献
64.
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66.
非饱和土渗流和变形强度特性的温度效应 总被引:1,自引:0,他引:1
高放核废料地下处置、高压电缆埋设和地热开发等工程的发展,使得温度对非饱和土基本力学性质影响的研究逐渐成为当前岩土工程的热点.从渗流特性和变形强度特性两方面出发,分析了温度对非饱和土基本力学性质的影响. 对于渗流特性,研究了温度对液相水和水蒸气运动的影响,并进一步综述了水热迁移模型的发展. 对于变形强度特性受温度的影响,从试验研究和理论模型入手,研究了非饱和土的变形和强度等随温度的变化规律,并在此基础上对温度的影响进行了总结.文中还指出了现阶段研究中存在的问题及今后的研究方向. 相似文献
67.
垂直与水平渗透作用下潜水非稳定渗流运动规律 总被引:6,自引:1,他引:5
对河渠边界控制的半无限含水层,建立垂向入渗与河渠水平渗透共同作用下的潜水非稳定渗流模型;利用Boussinesq第一线性化方法,通过Laplace变换,给出模型的解析解. 证明相关经典公式与模型特定解之间的转换关系,分析经典公式适用范围.根据模型解,逐一定量研究下述变量,如垂向入渗强度、河渠水位变动幅度、含水层结构参数如给水度和导压系数、计算点与边界之间的距离,对渗流过程的影响.这些变量的变化,对潜水位获最大上升速度的时间产生延迟效应;论证一些变量间产生等效延迟效应的条件.根据解的数学特征,讨论其对应的物理意义和潜水位变动规律. 相似文献
68.
XIAN Mo YAN Ji chang CHENG Tie xin KANG Yi jian LI Wen xing BI Ying li ZHEN Kai ji ** . College of Chemistry Jilin University Changchun P. R. China . College of Chemistry Northeast Normal University C 《高等学校化学研究》2002,18(3):303-306
IntroductionThe biosynthesis of unsaturated fatty acidshasattracted more attention in recent years. Forexample,linoleic and linolenic acids are importantmaterials for pharmaceutical and food industries.Besides,they can be used to synthesize paint,printing ink and surfactant,etc. A number ofmicroorganisms have been studied as potentialcommercial sources to produce unsaturated fattyacids[1] .Agricultural and industrial products,by-products,etc. have been employed in thecultivation of those orga… 相似文献
69.
随着倍半锗氧类化合物的合成及应用研究的日益广泛,含Ge_O键的烃基锗衍生物的合成及应用也逐渐引起了人们的关注.1984年,Lukevics等[1]合成了具有抗癌活性的介吗川类化合物,1990年Kakimoto等[2]报道了具有杀菌活性的环状烃基羧酸的合成与应用. 相似文献
70.
Dissolution and Seepage Coupling Effect on Transport and Mechanical Properties of Glauberite Salt Rock 总被引:1,自引:0,他引:1
Weiguo Liang Yangsheng Zhao Suguo Xu Maurice B. Dusseault 《Transport in Porous Media》2008,74(2):185-199
Potential high rates of aqueous dissolution are characteristic of salt rocks, and solute and mass flux through a soluble porous
medium are functions of solute concentration gradients and pressure gradients. Due to different dissolution properties for
different mineral components in glauberite salt rock, an interaction between mineral dissolution and solvent seepage arises,
driven by the hydraulic pressure gradient in the rock. The originally almost impermeable glauberite rock becomes an increasingly
permeable porous medium with dissolution, changing the transport and mechanical properties because of the progressive removal
of solid sodium sulfate (Na2SO4), one of the constitutive components of glauberite salt rock. Glauberite is often found in bedded salt rock deposits, and
the mineral glauberite has economic value and has been mined for many years in China. More economic and safe technologies,
such as controlled solution mining, are inherently attractive. Thus, investigations into relevant physical and mechanical
properties of glauberite in the context of solution mining have value, and to clarify glauberite behaviour, a series of experiments
were performed. It is observed through experiments that the permeability of the rock mass during dissolution of glauberite
is a function of the dissolution duration and the hydraulic pressure gradient applied to the system. For example, in laboratory
tests, after 49, 53 and 70 h of dissolution, the relationships between permeability (k—cm2) and pressure gradient (Δp—MPa across the specimen of length 100 mm) of the glauberite specimens were observed to be k = 0.24 for a Δp of 0.10, k = 0.30 for a Δp of 0.12, and k = 0.41 for a Δp of 0.18, with the empirical functional relationship becoming gradually steeper with pressure. Also, the triaxial compression
(mechanical) characteristics of glauberite salt rock change substantially after a period of dissolution: the compressive strength
under a confining stress of σ3 = 2.0 MPa changes initially from 46 to 11 MPa after 70 h of dissolution and seepage. Along with strength degradation, the
Young’s modulus (stiffness) changed from 4.6 to 0.5 GPa. Evidently, coupled dissolution and seepage rate greatly impact both
transport and mechanical properties of the rock as fabric evolves in a time-dependent manner. 相似文献