YJ-3000t型紧装式六面顶大腔体高温高压实验装置样品室的压力标定

固体、流体及其混合体系的高温高压实验一直是人们了解各种物质及体系的成分、结构、性状和过程的重要手段.因此,开展各种物质及体系的高温高压实验研究具有重要的理论和实际意义[1].在高温高压实验研究中,样品室内的压力通常必须已知.然而,对于采用固体物质作为传压介质的多面顶大腔体高温高压设备,由于传压介质的内摩擦会使得砧面压力与样品室内压力不一致,因此有必要对样品室内的压力进行标定.     

橄榄石的等温状态方程

利用金刚石对顶砧(DAC)高压装置产生高压,使用16∶3∶1的甲醇、乙醇和水混合液体作为传压介质,在室温下,40 GPa的压力范围内,对橄榄石(olivine)进行了原位高压同步辐射能量色散X射线衍射(EDXRD)研究。实验结果表明,在所研究压力范围内,采自张家口大麻坪天然新鲜橄榄石的结构稳定,未见相变和压致非晶现象发生。用Birch-Murnaghan方程对测得的V-p数据进行了数值拟合,当K′T0=4时,橄榄石的零压体弹模量为KT0=141.3±3.2 GPa。     

辉长岩脆-塑性转化及其影响因素的高温高压实验研究

本文利用高温高压多功能三轴实验装置,以NaCl为固体围压传压介质,在围压为450MPa~800MPa,温度区间为600℃~1150℃和应变速率为1×10-4~3.125×10-6/s条件下,对攀枝花辉长岩进行了流变学实验研究。实验结果表明,辉长岩围压在450MPa~800MPa条件下,温度在600℃时为脆性变形,700℃~850℃时为半塑性流动,含微破裂,大于900℃时为塑性流动。辉长岩的脆-塑性转化温度为700℃~900℃,主要影响因素为温度、围压和应变速率,同时存在双相流变学问题。      

急缺矿种金刚石合成固体密封传压介质叶蜡石资源开发研究及其对策

金刚石合成固体密封传压介质叶蜡石是一个急缺矿种,由于该资源的缺乏将会严重地阻碍我国超硬材料产业的发展。针对我国固体密封传压介质叶蜡石矿产资源的特点,提出了开发利用这种叶蜡石的措施和建议。     

急缺矿种金刚石合成固体密封传压介质叶蜡石资源开发研究及其对策

金刚石合成固体密封传压介质叶蜡石是一个急缺矿种,由于该资源的缺乏将会严重地阻碍我国超硬材料产业的发展.针对我国固体密封传压介质叶蜡石矿产资源的特点,提出了开发利用这种叶蜡石的措施和建议.     

高温高压下长英质麻粒岩的实验变形研究

对采自中国内蒙古的一种长英质麻粒岩进行了高温高压变形实验。实验在氯化钠传压介质活塞圆筒式压缩装置上完成。实验条件为ｔ／℃：６７０～９００，ｐ／ＧＰａ：１．１，ε／ｓ：１０－４～１０－７。用光学显微镜及高压透射电镜对实验样品的显微构造进行了观察研究。应用实验结果对大陆下地壳的某些变形特点进行了讨论     

饱和颗粒正冻土一维刚性冰模型的数值模拟

基于刚性冰模型,应用有限差分法离散方程组,对于饱和颗粒土开放系统的冻结过程进行了一维数值模拟,给出了冻结缘内参数的分布.计算过程中修正了刚性冰模型中分凝冰产生条件,提出以冻结缘内冰压与载荷的关系作为分凝冰产生的判据,计算得到的冻胀量与实验室冻胀实验的测量数据较为吻合.将计算结果与现场实测资料进行了比较,温度场、含水量分布等结果在分布规律方面与现场实测资料相符.     

一种高温高压下防止试块爆炸的新技术

本文采用在传压介质（如叶蜡石等）棱边附近埋置加强筋的方法，有效地防止了样品从传压介质中被挤压冲出来，从而提高了实验的成功率。对此方法的防爆原理，及加入加强筋后高压腔中的温度、压力等进行了讨论，实验在立方体高温高压装置上完成，压力测至6．0GPa，温度测至1740℃     

硅藻土负载羟基氧化铁对铬（VI）吸附的固体浓度效应研究

利用硅藻土负载羟基氧化铁颗粒作吸附剂对六价铬进行吸附和解吸附实验,探讨了硅藻土负载羟基氧化铁对六价铬的吸附机制和固体浓度效应。实验结果表明：在实验条件下,当吸附剂的用量从0.05 g增加到0.2 g时,六价铬的吸附量从23940.124μg/g降低到8575.415μg/g,吸附剂对Cr6＋的吸附存在明显的固体浓度（Cs）效应。吸附滞后角随着Cs 的增加而减小,吸附反应的可逆性增大。将实验数据分别用Languir和Freundlich吸附模型进行拟合,发现Freundl-ich吸附模型对实验数据拟合效果较好,表明该吸附反应以单分子层吸附为主。     

初论压溶的发育

压溶是一种应力作用下的化学平衡现象,早在上一世纪J.Thooso(1849),J.H.Poyting(1881)就作了系统研究,E.Rieke(1884)则进行了较全面的总结,称为利克原理。系指“受应力作用部分的固体比起自由表面的固体显示更高的溶解性”。通常都是以矿物晶体作为研究的对象。本世纪初,P.W.Bridgman(1916)通过实验提出一个旨在说明压溶现象的数学公式;     

Single crystal structure investigations under high-pressure of the mineral cordierite with an improved high-pressure cell

An improved single-crystal high-pressure anvil cell with beryllium-gaskets was used for the investigations of structure and lattice parameters of cordierite which had been heated in an Ar stream at about 1,000° C to remove natural water from its structural channels. The influences of pressure transmitting media were studied by using water as a pressure medium at pressures of 0.3, 0.9, 1.2, and 2.3 GPa and fluorcarbon, a liquid consisting of large molecules, at 2.2 GPa. Water, but not fluorcarbon, is able to enter the channels in the cordierite structure. Large variations in the lattice constants resulted from changing the pressure medium used. A previously supposed discontinuity of the b lattice constant at nearly 0.3 GPa could not be established by the measurements taken so that there is no evidence for a phase transition at this pressure. Possibly the observed tilting of two tetrahedra against each other in this structure could have led to this misinterpretion. When water, but not fluorcarbon, is used as a pressure medium at 2.3 GPa, an additional electron density peak, presumably a water oxygen atom, appears in the channels. The water prevents the channels from shrinking and fixes their width at a value comparable to that of a naturally hydrated cordierite. In one of the silicate-tetrahedra the Si-O bond lengths are compressed almost 1 percent (2.3 GPa). This process may initiate a phase transition at higher pressures.     

Surface waves in a cylindrical borehole through partially-saturated porous solid

Propagation of surface waves is discussed in a cylindrical borehole through a liquid-saturated porous solid of infinite extent. The porous medium is assumed to be a continuum consisting of a solid skeletal with connected void space occupied by a mixture of two immiscible inviscid fluids. This model also represents the partial saturation when liquid fills only a part of the pore space and gas bubbles span the remaining void space. In this isotropic medium, potential functions identify the existence of three dilatational waves coupled with a shear wave. For propagation of plane harmonic waves along the axially-symmetric borehole, these potentials decay into the porous medium. Boundary conditions are chosen to disallow the discharge of liquid into the borehole through its impervious porous walls. A dispersion equation is derived for the propagation of surface waves along the curved walls of no-liquid (all gas) borehole. A numerical example is studied to explore the existence of cylindrical waves in a particular model of the porous sandstone. True surface waves do not propagate along the walls of borehole when the supporting medium is partially saturated. Such waves propagate only beyond a certain frequency when the medium is fully-saturated porous or an elastic one. Dispersion in the velocity of pseudo surface waves is analysed through the changes in consolidation, saturation degree, capillary pressure or porosity.     

固液两相流体中的空泡振荡计算

本文导出了固液两相流体中球空泡的振荡方程,并用数值方法讨论了固体颗粒对它泡运动及泡壁压强的影响,得到了固相浓度、颗粒尺寸等因素与空泡运动之间的定性关系。在分析过程中,考虑了液体与颗粒之间力的双向耦合作用。     

Coupling of solid deformation and pore pressure for undrained deformation—a discrete element method approach

This paper presents a numerical scheme for fluid‐particle coupling that uses the discrete element method by taking into consideration solid deformation and pore pressure generation. A new water particle element is introduced to calculate pore water pressure due to porosity changes. The water particle element has the same size and shape as the solid element and experiences the same amount of deformation. On the basis of the effective stress principle at the element contact, the total force is equal to the sum of the force transmitted through the solid element contact and the water particle force due to pore water pressure. Analytical solutions of traditional soil mechanics problems, such as isotropic compression and consolidated triaxial undrained test, are used to quantitatively validate the proposed model. The numerical results show good agreement between the model and the analytical solutions. The model therefore provides an effective method to calculate pore pressure in a porous medium in discrete modeling.     

Poroelastic behaviour of fine compacted soils in the unsaturated to saturated transition zone

The behaviour of quasi-saturated materials is important to consider when designing cuttings and embankments in which earthwork materials are compacted to the optimum proctor density. Under this condition, the in-pore gaseous phase takes the form of air pockets and bubbles embedded within the liquid phase, which significantly affects the overall behaviour of the soil. The assessment of highly saturated soils thus requires a precise understanding of hydro-chemo-mechanical couplings between the entrapped air, the in-pore liquid and the solid skeleton. This paper presents a fully coupled poromechanical model that separates the kinematics and the mechanical behaviours of the phases in their interactions with each other (e.g., liquid water, dissolved air, gaseous air and solid matrix). The assumptions about the entrapped air behaviour are defined from a bibliographic study, and linear elastic behaviour is used for both the liquid phase and the solid skeleton. The model is implemented in the FEM code COMSOL and is subsequently used to simulate oedometric tests under different loading paths: undrained compression or imposed liquid pressure variation at constant stress. The behaviour, which shows a continuous transition from unsaturated to saturated, is logical and consistent with available experimental data.     

二维饱和土体动态孔隙率及相关动力响应特性研究

饱和多孔介质的动力响应研究在众多工程领域具有重要意义。充分考虑孔隙率的变化规律与影响因素,有利于合理揭示饱和多孔介质的相关力学行为。为此,将动态孔隙率模型与用于表征饱和多孔介质动力特性的u-U-p型方程结合,构建相应的非线性力学模型,利用Comsol Multiphysis PDE求取相应的数值解,以此研究不同透水条件下,受谐波载荷激励的二维饱和土体的孔隙率、变形量及孔隙水压力的变化规律。结果表明：孔隙率的变化与土骨架的体应变及孔隙水压力直接相关,土体压缩过程中,孔隙率相应减小,土骨架与孔隙流体的相互作用增强,土体运动时所受阻力增大,其无量纲竖向位移小于孔隙率被视为常数时的情况,在此条件下,由于土体的变形量减小,其孔隙水压力也相对减小。故充分考虑动态孔隙率,有利于更加精确地研究等饱土体和多孔介质的相关力学行为。此外,土体上表面透水条件下,孔隙流体可以从土体表面自由排出,土骨架承受的载荷更大,与不透水条件相比,土体孔隙率、竖向位移、孔隙水压力等变化更为显著。     

Leaching process and kinetics of manganese in low-grade manganese ore

Manganese was extracted from leaching low-grade manganese ore in sulfuric acid medium. The effects of granule diameter, leaching time, liquid/solid ratio (V/W) and the concentration of sulfuric acid were investigated through orthogonal and single factor experiments. The experimental results showed that the optimal leaching conditions are, size of 0.054mm, 120 minutes of reaction time, 3(V/W) of liquid/solid ratio and 30% of the concentration of sulfuric acid (g/g). Under those conditions, the leaching efficiency is 96.73%. The kinetics of the leaching process is in accordance with the characteristics of fractal reaction.     

近临界特性的地层水及其对烃源岩生排烃过程的影响

研究利用特制的地层孔隙热压模拟实验装置, 开展了模拟地层孔隙空间高压液态水热体系烃源岩生排烃模拟实验.模拟实验施加的流体压力为38±2 MPa, 温度为290~390 ℃.模拟实验结果显示了有关高压液态水及其与之相联系的流体压力和孔隙空间等因素对烃源岩生排烃影响作用的一些重要现象, 实验发现高压液态水介质条件有利于液态油的生成和保存, 不利于液态油向气态烃的转化, 而且干酪根的生烃潜力和排油效率有一定的提高.这些新的实验现象可能主要与近临界特性的高压液态地层水的作用有关, 进一步推断近临界特性的高压液态水参与干酪根向油气的转化反应, 增加了水对油气的溶解能力.在地下实际烃源岩生排烃的温压(100~200 ℃, 30~120 MPa)条件下, 岩石孔隙中的地层水是一种相对低温高压压缩液态水, 这种地层水可能具有近临界特性, 对烃源岩生排烃过程有重要影响.但目前对这种现象的机理和石油地质意义还知之较少.因此, 加强高压地层水近临界条件下烃源岩生排烃热压模拟实验研究, 对进一步深入理解地层条件下的近临界水介质、流体压力、孔隙空间因素对生排烃过程的影响, 深化烃源岩生排烃机理的探讨, 建立地质尺度上的烃源岩生排烃动力学模型, 都具有重要的理论和实际意义.      

储层流固耦合的数学模型和非线性有限元方程

根据饱和多孔介质固体骨架的平衡方程和多孔介质中流体的连续性方程,建立了储层流固耦合数学模型。模型中引入了Jaumann应力速率公式描述多孔介质固体骨架的大变形效应,并考虑了地应力、初始孔隙压力、初始流体密度和初始孔隙度对耦合模型的影响。基于与微分方程等价的加权余量公式,在空间域采用有限元离散,对时间域进行隐式差分格式离散,导出了以单元节点位移和单元节点孔隙压力为未知量的储层流固耦合的非线性有限元增量方程。该模型在石油工程中有广泛的应用,为储层流固耦合的数值模拟奠定了理论基础。     

饱和土地下源u-P形式解答动力响应计算

一直以来,由Biot孔隙弹性动力方程得到的饱和土地下源Green函数都是u-w形式（u为固相介质位移,w为流相相对于固相的平均位移）。应用两相介质纵波解耦理论,得到了饱和土半空间地下点源荷载的u-P形式（P为孔压）Green函数频域解答;克服了u-w形式Green函数在边界元（BEM）积分时的增根影响。再由Hankel反演,结合Somigliana表象积分,完成BEM计算。并以计算结果分析了地下集中力作用时,饱和土位移、孔压、排水量等动力特性,这对地铁等交通工程、地震工程、土-结构动力相互作用（SSI）的响应计算都具有较重要应用价值。