渗透释水规律在深层粘性土变形沉降预测中的作用

笔者对海口市地下水开采漏斗区深层饱和粘性土进行模拟抽水作用下固结渗透联合试验和高压固结试验等室内试验研究，认为深层正常固结和超固结的饱和粘性土，在地下水开采水位持续降低的情况下仍会释水变形；土的物理力学参数均为变量。初步探讨粘性土孔隙水渗透、释水规律，提出运用该规律预测地面沉降的方法。     

长江口及其邻近海域粘性泥沙的数量与输移

长江口的粘性泥沙有89.6%以上来源于长江补给区,一部分来源于废黄河与黄海补给区。长江补给区的粘性泥沙的汇入百分数及其输沙量两者均为已知,据此计算出长江口粘性泥沙沉积量为4.554×10~7t/a,从长江口输向杭州湾与东海补给区的粘性泥沙输沙量为2.247×10~7t/a,废黄河与黄海补给区输向长江口的输沙量为2.730×10~7t/a。长江口粘性泥沙的数量同1915年与1963年实测地形图比较量算的数量为4.469X10~7t/a基本相符。     

粘性泥石流稳定运动的力学分析

重点论讨的是，泥石流形成之后的流通段粘性泥石流稳定运动特征。以野外观察为基础，提出了沙石体整体滑动的运动模式和膨胀流体的运动模式，并对这两种稳定运动模式提出了各自的计算方法及其参数的选用意见。     

粘性泥石流应力应变特征的初步试验研究

采用自己最新研制的泥石流流变仪，测试自然界活泥石流体的样品，发现粘性泥石流体在低速率受剪时具有应力过冲和剪切稀化等特征。这些特征的讨论和认识，为进一步深化泥石流模型理论研究奠定了基础。     

粘性泥石流残留层与泥深的关系分析

粘性泥石流泥深的观测数据过去大部分不包含残留层厚度,认为当后继粘性泥石流通过残留层时,残留层是不动的,泥深从残留层表面起算。本文通过大量的泥石流原型观测和简易模型试验表明,当后继泥石流通过时,残留层除底部很薄的一层不动外,都是运动的,并有三种运动形式,泥深应包含残留层。残留层的厚度一般为20～60cm,这样对过去不包含残留层厚度的泥深观测数据应进行更正,粘性泥石流流量和输沙率也需相应增加。     

粘性泥石流复式沟床水力特性探讨

天然粘性泥石流沟床都是复式断面，不同滩槽宽度比在不同的泥位条件下其水力要素（过流面积、湿周、水力半径）有所不同。引用天然河流水力计算方法，对概化的复式沟床泥石流流量计算表明：滩槽宽度比对滩、槽过流能力及流量分配有较大的影响；同一滩槽比情况下，主槽过流与全断面过流量之比随泥深增大而逐渐减小，而滩面过流与全断面过流量之比却逐渐增大；泥石流复式沟床滩槽影响可用协同度表示，计算分析表明，滩槽比相同时，随泥深增加，滩、槽影响逐渐减小。     

成昆铁路北段粘性泥石流浆体流变参数的时间效应

对成昆铁路北段一些粘性泥石流浆体所作的剪切试验结果表明,流变参数[含:表观粘度η和屈服应力(极限静切力)τ]随时间推移而变化。粘性泥石流浆体的流变参数具有时间依赖效应,随剪切时间推移而递增。粘性泥石流浆体呈现出反触变性的流变行为,随时间推移而变稠,就此越发变得不易流动。     

粘性泥石流体的应力应变特征和应力本构关系的研究

通过粘性泥石流体阵性流的野外观测和最新研制的泥石流流变仪应用,含有砾石的粘性泥石流体具有明显的应力过冲、触变能量、剪切稀化和双屈服应力等流变特征被得到研究。粘性泥石流应力应变的自组织临界特性分析表明,泥石流的规模与频率间存在着幂定律关系。粘性泥石流体在低速率区启动初始段,其应力本构关系可用剪切稀化的幂定理方程来描述。粘性泥石流体在剪切速率区流动剪切段的应力本构关系,应包含滑动摩擦作用的零次项和反映惯性碰撞的平方项,具有屈服应力和剪切膨胀的流变特征。     

新经济地理学视角下中国纺织业区际转移的粘性分析

如何破除产业区际转移粘性,实现区域经济协调发展已成为近年来国内研究的热点问题。基于新经济地理学视角,综合运用区位熵、产业集聚变动指数和面板数据的门限回归方法,对2000-2010年中国纺织业转移的时空特征及区际转移产生粘性的原因进行了研究。结果表明,尽管东部纺织业已出现明显的转移趋势,但就其跨区向中西部转移而言仍具有很强的粘性,其原因在于:1纺织业对本地市场具有较强的依赖性,因而在市场接近效应的作用下东部纺织业向中西部地区的转移存在一定的市场阻力;2纺织业集聚的外部规模效应仍在增强,特别是东部部分省份的纺织业未来仍有较强的集聚动力;3东部由于其特定区位优势和经济发展非均衡的特点为该地区纺织业在其内部省份间的调整提供了回旋余地。     

粘性泥石流沟口回淤实验研究

泥石流在堆积区进行堆积时,常在沟口形成回淤并造成灾害.为了探讨泥石流在沟口回淤的发展过程、影响因素及其预测,开展了4组107次泥石流连续堆积和4组共21次单次堆积实验.实验结果表明,粘性泥石流在沟口回淤的发展过程中,累积回淤长度与泥石流累积总量呈线性正相关,相对累积回淤坡度与泥石流累积总量呈对数负相关,根据相对累积回淤坡度的变化将粘性泥石流沟口回淤的发展过程分为三个阶段;在泥石流总量相同的情况下,回淤长度随泥石流重度增大而呈线性增大,随堆积区坡度增大而呈线性减小,随流通区坡度增大而成对数减小.相对回淤坡度随泥石流重度的增大呈线性减小,随堆积区坡度增大而呈线性增大,随流通区坡度增大而呈线性增大;在泥石流总量不同的情况下,随泥石流总量的增大,其沟口回淤长度随之呈线性增大,而相对回淤坡度随之呈线性减小;在粘性泥石流沟口回淤发展过程及其影响因素分析的基础上,采用多元线性回归的方法,建立了粘性泥石流在连续堆积及单次堆积情况下沟口回淤的经验预测公式.     

Viscous gravitational relaxation

Summary This paper is concerned with a detailed examination of the response of Maxwell models of the planet to surface mass loads. Particular attention is devoted to an examination of the factors which determine the isostatic response since the understanding of this response is crucial in a number of different geodynamic problems. One particular example which we discuss in detail is concerned with the prediction of free air gravity anomalies produced by large-scale deglaciation events. Using the methods developed here we are able to provide the first direct assessment of the importance of initial isostatic disequilibrium on the observed relative sea-level variations and free air gravity anomalies forced by the melting of the Laurentide ice sheet. We are therefore able to estimate the extent to which such initial disequilibrium might influence the inference of mantle viscosity from isostatic adjustment data. Our calculations establish that free air gravity data, although they are sensitive to the degree of initial disequilibrium, provide an extremely high quality constraint upon the viscosity of the lower mantle.     

Electromagnetic and Viscous Damping of Core Oscillations

Summary. A detailed investigation of the interaction of core oscillations with the main magnetic field is made. Selection rules and interaction coefficients are obtained. Although the strengths of the interactions vary over nearly three orders of magnitude, all are extremely weak. Ohmic and viscous dissipation are considered in parallel calculations. It is found that core oscillations are almost unaffected by either damping mechanism. Most of the Ohmic dissipation takes place within a few skin depths of the boundary. Viscous dissipation is estimated only for the body of the liquid core. Even though it is expected to be much larger near the boundaries, it would seem unlikely to be sufficiently large to be of any significance. Our conclusion is that core oscillations are virtually free of damping. In a subadiabatic core, gravitational oscillations might be persistent enough to sustain an oscillatory geodynamo.     

Stability of Planetary Interiors

Summary Many accept thermal convection within the mantle of the Earth as the driving mechanism for continental drift. It is also of considerable interest to determine whether thermal convection is occurring within Venus, Mars, and the Moon. In this paper a systematic treatment of the stability of planetary interiors is given. The thermal stability problem for a layer of fluid heated from below is solved when the viscosity of the fluid increases exponentially with depth. For a semi-infinite fluid with exponentially increasing viscosity the critical Rayleigh number based on the surface viscosity and the scale length of the viscosity increase is found to be 30 for a fixed surface boundary condition and 23 for a free surface boundary condition. This stability analysis is also extended to include volume heat release. The thermal stability of the interiors of the Earth, Venus, Mars and the Moon is examined. Using temperature-depth profiles in the literature and a theoretical expression for the viscosity of a crystalline solid based on diffusion creep, viscosity depth profiles for planetary interiors are obtained. Because of the strong pressure effect the viscosity within the Earth and Venus increases greatly from a near surface minimum. For Mars the increase is less pronounced and within the interior of the Moon the viscosity is nearly constant. For all the cases considered the planetary interiors are found to be thermally unstable. Because of the dependence of viscosity on depth the interiors of the Moon and Mars are found to be considerably less stable than Venus and the Earth. It is concluded that thermal convection is occurring within the planetary bodies considered.     

On the existence of a second scale of convection in the upper mantle

Summary. This paper is concerned with an examination of the possibility that there might exist a small scale of convective circulation beneath the oceanic lithosphere. Recent suggestions that this might be the case have been made in an effort to understand why the bathymetry of the sea-floor deviates from the prediction of boundary layer theory for ages in excess of about 100 Ma. The energy source which sustains the secondary motion is supposed to be found in the steep temperature gradient near the planetary surface which is itself presumably maintained by the large-scale convective circulation associated with plate creation and destruction. Here we investigate the extent to which the temperature dependence of viscosity may act so as to stabilize the upper boundary layer against disruption by such secondary instability. If the viscosity profile is monotonie and the asymptotic upper mantle viscosity is about 10²²poise, as suggested by post-glacial rebound data, then the existence of the second scale is extremely unlikely. On the other hand, if a sufficiently pronounced low viscosity zone does exist under old sea-floor then the development of such a second scale cannot be ruled out completely. Some recently obtained geophysical evidence is reviewed which suggests that this is unlikely to be the case.     

Planetary shape: internal constraints for small bodies

Summary. This paper describes the attainment of sphericity, or equivalent isopotential forms, for the surface of small Solar System objects (linear dimensions ∼ 300 km) as a consequence of viscous relaxation (creep).
The viscous relaxation time is shown to be directly proportional to the viscosity and proportional to the inverse square of the linear dimensions of the object. Since the effective viscosity varies very rapidly with temperature the detailed internal temperature distribution will in most cases significantly affect the rate of relaxation. If this temperature is sufficiently high during any phase of the object's history, virtually complete relaxation will have occurred.
Because the thermal relaxation time is usually less than the age of the objects considered, and because differentiation and convection are unlikely to occur, a simple model for the thermal regime within the object is easy to develop from which the viscosity is determined at various depths. It is shown that a body is more likely to relax if it is composed of a mixture of ice and silicate rock rather than either pure substance. The relaxed shape of Phoebe and the irregular shape of Hyperion may be accounted for by a lower radiogenic content in Hyperion, a hypothesis supported by albedo observations. The assumption that the object can be treated throughout as having a viscosity corresponding to the mean internal temperature is of course far from exact. It is shown that a plastic core may be formed which can eventually cause fracture of the outer harder shell and consequent sudden relaxation to an approximately spherical shape.     

A magnetic coupling occurring in partial self-reversal of magnetism and its association with increased magnetic viscosity in basalts

Summary. Samples of Rauher Kulm basalt containing titanomagnetite were heat treated to exhibit partial self-reversal caused by a CRM acquired by an exsolved or 'daughter' phase reversely coupled with the original or 'mother' phase. Alternation of thermal demagnetization with alternating field (AF) demagnetization from progressively higher values of peak AF showed that the two phases were mainly demagnetized together. The coercivity of the coupled. phases exceeded that of the natural sample.
Screening of the daughter phase by a shell of mother phase was demonstrated using large pieces of synthetic titanomagnetite with segregated magnetite and applying a field during the process of self-reversal. Saturation magnetization was measured to indicate the relative proportion of the phases.
Measurements of viscous magnetization of Rauher Kulm samples confirmed that heat treatment caused increased viscosity, but with anomalous anisotropy. After a certain time the viscosity coefficient changed sharply. Explained in terms of grains present such viscous growth initially involved growth of the two phases in opposition. Owing to its greater volume the mother phase growth, which involved low-energy domain wall barriers, was assumed to be the greater. When there were no more daughter phase nuclei of sub-critical volume available, the mother phase growth continued unopposed. Analysis of available growth curves showed that the magnetic viscosity coefficient of the daughter phase was related to the viscosity coefficient for this unopposed growth, which depended on the sum of the external field and the change of the back field produced by the daughter phase. Small granules within grains could be a factor in increasing viscosity due to domain wall movement.     

On the penetration of a hot diapir through a strongly temperature-dependent viscosity medium

Summary. The ascent of a hot spherical body through a fluid with a strongly temperature-dependent viscosity has been studied using an axisymmetric finite element method. Numerical solutions range over Peclet numbers of 10⁻¹– 10³ from constant viscosity up to viscosity variations of 10⁵. Both rigid and stress-free boundary conditions were applied at the surface of the sphere. The dependence of drag on viscosity variation was shown to have no dependence on the stress boundary condition except for a Stokes flow scaling factor. A Nusselt number parameterization based on the stress-free constant viscosity functional dependence on the Peclet number scaled by a parameter depending on the viscosity structure fits both stress-free and rigid boundary condition data above viscosity variations of 100. The temperature scale height was determined as a function of sphere radius. For the simple physical model studied in this paper pre-heating is required to reduce the ambient viscosity of the country rock to less than 10²² cm² s⁻¹ in order for a 10 km diapir to penetrate a distance of several radii.     

Radial resolving power of far-field differential sea-level highstands in the inference of mantle viscosity

For two decades leading to the late 1980s, the prevailing view from studies of glacial isostatic adjustment (GIA) data was that the viscosity of the Earth's mantle increased moderately, if at all, from the base of the lithosphere to the core–mantle boundary. This view was first questioned by Nakada & Lambeck , who argued that differential sea-level (DSL) highstands between pairs of sites in the Australian region preferred an increase of approximately two orders of magnitude from the mean viscosity of the upper to the lower mantle, in accord with independent inferences from observables related to mantle convection. We use non-linear Bayesian inference to provide the first formal resolving power analysis of the Australian DSL data set. We identify three radial regions, two within the upper mantle (110–270 km and 320–570 km depth) and one in the lower mantle (1225–2265 km depth), over which the average of viscosity is well constrained by the data. We conclude that: (1) the DSL data provide a resolution in the inference of upper mantle viscosity that is better than implied by forward analyses based on isoviscous regions above and below the 670 km depth discontinuity and (2) the data do not strongly constrain viscosity at either the base or top of the lower mantle. Finally, our inversions also quantify the significant bias that may be introduced in inversions of the DSL highstands that do not simultaneously estimate the thickness of the elastic lithosphere.     

稀性泥石流容重计算的改进方法

稀性泥石流的沉积样的粒度不能反映稀性泥石流的实际粒度,过渡(亚粘性)泥石流的沉积样的粒度也不能完全反映亚粘性泥石流的实际粒度.通过分析稀性泥石流和亚粘性泥石流沉积样中的粗颗粒和细颗粒组成的百分比与稀性泥石流和亚粘性泥石流的实际粒度分布关系,得出稀性泥石流以细颗粒为主,>5 mm的粗颗粒的百分比较小,大多数稀性泥石流的沉积样中这部分粗颗粒百分含量被夸大.去掉稀性泥石流沉积样中>5 mm的粗颗粒可以修正被夸大的粗颗粒比例,由此粒度分布和修正公式计算的稀性泥石流容重与实际容重吻合较好.去掉亚粘性泥石流沉积样中>20 mm的粗颗粒,可以修正亚粘性泥石流的粒度分布,由此粒度分布计算的亚粘性泥石流容重与实际容重吻合更好.     

交错齿槛槽排导粘性泥石流的试验

排导槽是一种结构简单、效果明显、用途广泛的泥石流防治措施,在总结东川槽、V型槽等现有排导槽槽型优缺点的基础上,结合一种新槽型——交错齿槛型泥石流排导槽展开试验研究。提出排导槽排导指数概念,即直接反应排导槽排泄能力的参数。利用室内水槽模型试验,通过改变交错槽纵比降、齿槛间距、夹角等参数,得出排导指数与上述参数的关系,试验结果表明:1.与东川槽相比,交错齿槛槽的排导能力有大幅度的提升,最大增幅达74%,表明交错齿槛有较强的挑流排泄能力,能有效解决东川槽等存在的淤积难题;2.不同比降下,交错槽主要设计参数组合存在差异,其中10%与15%比降下,60°齿槛间距为30 cm时,交错槽的排导指数最大,排导能力最强;而12%比降下,60°齿槛间距为40 cm为最优组合;3.小角度齿槛(60°)齿槛挑流排导能力较大角度(80°)更强,更适合坡降较小的排导槽;齿槛角度越大,齿槛的挑流能力有限,阻流作用越明显,对需控制流速及洪峰流量的泥石流,可考虑采用大角度齿槛。