岩石坚硬程度对核电厂地基-基础地震响应特征的影响分析

考虑核电厂地基-基础的动力相互作用,应用显式动力有限差分法分析了地震作用下极软岩、较软岩、坚硬岩上核电厂建筑结构基础的地震响应特征,比较了岩石坚硬程度对基础加速度反应谱的影响。研究表明：随着岩石坚硬程度的提高,核电厂建筑物结构基础的地震响应有增加的趋势;在周期轴上,基础处的加速度反应谱曲线会随着岩石坚硬程度的提高逐渐向短周期（高频段）方向移动。在高频段,建造于较坚硬岩石上基础结构的加速度反应谱值偏大;在中等频段,建造于较软岩石上基础结构的加速度反应谱值偏大;在低频段,岩石坚硬程度对加速度反应谱的影响不显著。     

土压缩模量预测回归分析方法

在土压缩模量Es的分析计算中,常用的分析方法是根据土的e-p曲线试验资料建立公式求解,本文引入了数学上的回归分析方法来探讨Es与其它各项物理力学指标参数之间的相关关系,旨在找出对Es影响最显著的指标参数,并建立最优回归方程式,以此来预测Es。研究结果表明:该方法通用性强,应用范围广,亦可推广应用于其它相关领域。     

Strains of scattering of near-field of a point source

Three dimensional scattering of near-field is studied for dilatation and rotation in the time domain. The perturbation method is applied to solve the equation of motion for the first order scattering from a weak inhomogeneity in an otherwise homogeneous medium. The inhomogeneity is assumed close enough to the point source so that the near-field intermediate wave is dominating over the far-field sphericalP andS pulses. The integral expressions are derived to relate dilatation and rotation of scattering to the radial fluctuations of velocities and density in the inhomogeneity. These integrals are solved to calculate the strains of scattering from (a part of) an inhomogeneous spherical shell of arbitrary curvature. Variable curvature may allow the shape of inhomogeneity volume element to change uniformly from spherical to rectangular. Rotation of scattering from a spherical shell is independent ofP wave velocity inhomogeneity. Dilatation of scattering does not involveS wave velocity inhomogeneity but its gradient. The back scattering results are obtained as a special case. Strains are computed numerically, for hypothetical models to study the effects of various parameters viz., velocity inhomogeneity, distance of source from inhomogeneity and from receiver, and thickness of inhomogeneity. The curvature of the spherical shell is varied to study the effects of the shape of inhomogeneous volume element on scattering.     

Causes of salinization of the Gulf of Taganrog

Using the database of automatic hydrometeorological stations, installed in the Don RIver delta and Taganrog Bay seashore, the sources of the anomalois scale water negative surge and salinization of the Azov Sea under conditions of low river flow in 2015–2016 are studied. The new schemes of stratification and advection of salty sea waters in the Don River mouth under different weather conditions, water discharge and levels are given.     

土石坝心墙水力劈裂分析

简要分析了水力劈裂的发生条件、力学机理。基于水压楔劈机理,利用有限元方法建立了一种水力劈裂的发生判定方法。该方法假定心墙预先存在局部渗透弱面（裂缝）,通过将裂缝位置的单元材料改为裂缝软材料,考虑库水进入裂缝后对裂缝周围土体的作用,建立水力劈裂分析的平面有限元模型,确定裂缝端部垂直于裂缝面的正应力,进而依据该正应力判断水力劈裂发生的可能性,该方法同时可模拟水力劈裂的发展过程。     

土钉支护失稳分析

某基坑采用复合土钉墙支护,开挖至坑底后,基坑北侧发生失稳事故。本文就其事故发生原因作一探讨。     

下扬子区三叠纪古地理演化

下扬子区在三叠纪期间接受了早-中三叠世海相碳酸盐沉积、中-晚三叠世海陆交互相和陆相湖沼沉积.沉积相带的空间分布和古地理格局的变迁明显地受到区域构造的控制.区内盆地发育与演化是在华南板块与扬子板块、扬子板块与华北板块相互作用的背景下进行的.早-中三叠世末期的印支运动是下扬子区构造-古地理格局改变的决定性因素,使下扬子海盆闭合,沉积类型由海相沉积变为陆相沉积.下扬子区三叠纪古地理的演化特征也为板块碰撞提供了沉积证据.     

多年冻土融沉性分类研究

在冻土工程中,冻土的融沉性评价是工程地质勘察的主要内容之一,融沉性分类是冻土地基基础设计施工的重要依据．根据345个冻土原状样品融沉压缩试验数据,提出了细砾、砂土、粉土、黏性土、泥炭化黏性土和泥炭质土等6类土的融沉系数一含水量或融沉系数一超塑含水量线性回归方程式,得到与各融沉性分级相应的界限含水量或界限超塑含水量．最后...     

电信网络两类逻辑图自动生成算法

为解决电信手工绘制的逻辑图不易维护的问题,研究了电信带方向逻辑图和不带方向逻辑图的自动生成算法.算法是从数据库提取缆线的路由信息,用深度优先的方式遍历缆线经过的所有坐标,采取回溯的方式,计算缆线在每个点的偏移值,调整缆线顺序,自动绘制逻辑图.产生的逻辑图没有不必要的交叉,避免了传统的手工绘制.结果表明,对于常用的电信逻辑图,自动生成算法是可以满足要求的.      

Reaction of zoning of garnet

Compositional zoning of garnet in metamorphic or igneous rocks preserves evidence of the equilibration history of the sample and can be interpreted in terms of a growth-fractionation, diffusion-exchange, or diffusion-reaction model. Diffusion zoning is usually assumed to result from exchange reactions between garnet and other phases as the partitioning coefficient varies in response to changing environmental conditions, primarily temperature. However, in many natural environments where garnet grew originally in divariant equilibrium with other phases, changing conditions can promote continuous or “divariant” reactions and consequent compositional shifts of phases that can be much greater in some systems showing these reactions than those related to the small changes of partitioning. Diffusional zoning related to overstepping of these continuous reactions must be related to incongruent reaction and necessitates formulation of a kinetic diffusion-reaction model involving moving phase boundaries as well as solid-state diffusion. Three samples containing zoned garnets from the metamorphic aureole around the Ronda ultramafic intrusion in southern Spain are used to illustrate two possible models of diffusion-reaction processes. The examples are particularly informative because the reactions are demonstrably irreversible and evidence of the reaction system is preserved. Partitioning data indicates that compositions of product phases are not in equilibrium with the original garnet and do not vary with extent of reaction; therefore, exchange reactions with garnet were not possible and garnet changed composition only by incongruent reaction. After a small amount of reaction, Mg/Fe of the rim composition approaches a value apparently in equilibrium with product phases, but the garnets are zoned inward to the original garnet composition preserved in the interior. Grossularite content is approximately constant and spessartite content variable but small, thus, the rim composition of pyrope or almandine is assumed to be fixed by the external reaction process and is taken as a boundary condition in the following models. The zoning profile of pyrope or almandine component between the fixed rim and core compositions (assumed to extend to ∞) is described in semiinfinite, half-space models appropriate for large garnets with narrow rims. The first model corresponds to a reaction system in which all garnet compositions are metastable (case 1) and zoning depends on the independent variables of the diffusion constant, velocity of the interface between garnet and matrix, and time. The second model, corresponding to systems in which the initial garnet composition is metastable but an equilibrium composition is stable (case 2), depends on the independent variables diffusion constant, time, and a function of reaction compositions. In case 1 the consumption velocity is assumed constant and a steady state zoning profile is reached at large time, whereas, in case 2, the velocity decreases with the concentration gradient and steady state is not possible. The models were tested using a reaction time estimated from cooling models of the aureole, mass of garnet consumed, determined petrographically, and phase compositions. The two cases are somewhat independent in that different parameters are independent variables. The estimate of the diffusion constant of 10^?18±2 cm²/sec (assumed to be a mutual or binary coefficient for almandine and pyrope) is considered reasonable for the temperature range of reaction (probably 600–900° C), and the two models are consistent considering the probable error and possible real temperature differences. It is obvious that details of the metamorphic reaction system must be known to successfully apply diffusion models. Kinetic models, involving consumption or growth of the phase as well as diffusion are probably necessary when dealing with natural rocks. Several possible and interesting complications, such as cross coupling between components, can be investigated if more data were available. Experimental determination of diffusion constants allow natural reaction rates to be estimated by this method. Diffusion zoning is an important consideration that could increase the efficiency of experimentation with chemically recalcitrant phases.     

含水层渗透性空间分布的指示克立格估值

详细介绍了指示克立格估值计算的理论和方法。以指示变异函数为基本工具分析了华北某地区第四系含水层渗透性空间分布的结构特征,结果表明该地区含水层渗透性存在明显的各向异性特征。水平方向上,X轴方向的相关性较Y轴方向的好,Z轴的相关性最差。用指示克立格法对未采样点处进行估值,估值结果显示含水层渗透性由山前向滨海逐渐变低,在垂直方向上,渗透性变化不明显,浅部比深部略好;同时给出了估计精度,并认为对估计精度不高的区域可通过增加适当的工程加以控制。最后用交叉验证法对估值结果进行了检验,证明建立的指示变异函数模型合理且估值效果较好。这一实际应用表明指示克立格法可以很好地描述第四系含水层渗透性的空间分布规律。     

Outline of metallogeny of copper deposits of Cuba

Copper deposits of Cuba belong to the Jurassic lead-zinc-copper, Cretaceous copper and Paleogene copper complexes, which differ substantially in their formation conditions. The island is differentiated into a number of metallogenic zones formed at the initial and early stages of the Cuba folded province. Pinar del Rio, Pinos, Trinidad and Oriente zones, of an intrageanticlinal nature, are prospective with respect to copper vein deposits of the lead-Zinc-copper complex. The Sasa and Cauto zones - intrageosynclinal - are prospective with regard to copper-pyrite and copper vein deposits of the Cretaceous complex. A metallogenic study of the island is indicated in planning the exploration of its copper prospects. -- AGI Staff.     

Kinetics of dehydration of Ca-montmorillonite

Isothermal thermogravimetric experiments have been carried out to determine the reaction kinetics of the dehydration processes in fuller's earth, a natural Ca-montmorillonite. Dehydration in swelling clays is a complex reaction, and analysis of the thermogravimetric data using empirical rate equations and time-transformation analysis reveals that the nature of the rate controlling mechanism is dependent upon both the temperature regime of the sample as well as the extent of reaction. For fuller's earth, we find that the dehydration kinetics are dominated by a nucleation and growth mechanism at low temperatures and fractions transformed (stage I), but above 90 °C the last stages of the reaction are diffusion controlled (stage II). The activation energy for dehydration during stage I is around 35 kJ · mol⁻¹, whereas the removal of water during stage II requires an activation energy of around 50 kJ · mol⁻¹. These two stages of dehydration are associated with primary collapse of the interlayer (stage I) and movement of water that is hydrated to cations within the interlayer (stage II). Received: 28 August 1998 / Revised, accepted: 27 January 1999     

Role of assimilation of mantle material in petrogenesis of basalts

Upon consideration of published data and on the assumption that an alkalic-doleritic magma of the given composition may assimilate, for example, 10% of the ultrabasic substance of the mantle in one case and the same percentage of acidic substance of the crust in another, the calculated product should be either a basalt of the continental olivine-basaltic formation or a traprock of a young platform. -- V.P. Sokoloff     

边坡滚石运动轨迹分段循环算法

边坡滚石是在基本建设中常遇到的一种工程灾害。其防护结构的设计依据主要是边坡滚石的运动轨迹,因而要对这种灾害进行防治,首先要确定滚石的运动轨迹。根据落石运动全过程的三个阶段,即滚动(滑动)运动阶段、抛物运动阶段和与坡面碰撞阶段,利用分段循环算法分别得到了三个运动阶段的运动速度计算公式。以某岩质边坡构建相似模型,将该理论公式应用于落石运动轨迹预测,验证了公式的可行性和有效性。与现有方法相比,分段循环算法具有计算原理简单明确、易于使用等优点。该方法可用于斜坡区滚石运动特征的预测,并可作为斜坡区滚石灾害防治的依据。     

群锚静载试桩研究

应用全长粘结式锚杆群代替反力桩进行桩基静载试验,不但工艺简单、施工方便,而且工期短、成本低。通过对锚杆的力学分析和现场量测,获得了锚杆的受力和位移特征,为这类锚杆的设计与计算提供理论依据。     

Results of Marine Radioecological Study of Fjords of Western Spitsbergen

The patterns of the distribution of technogenic radionuclides ¹³⁷Cs and ⁹⁰Sr in the water mass and bottom deposits of three fjords of Western Spitsbergen (Isfjorden and its arms Grønfjorden and Billefjorden) were studied. The hydrological processes affecting migration of radionuclides in these water bodies were described. It was shown that the ice sheet of the archipelago that accumulates atmospheric precipitation is a source of radioactive contamination of the marine environment of the coast. Technogenic isotopes were accumulated during nuclear weapon testing in the second half of the twentieth century. The current climatic changes strengthen the role of glaciers in the contamination of arctic seas. It was noted that extrema of the ¹³⁷Cs and ⁹⁰Sr specific activity is mainly concentrated in the areas of glacier runoff discharge.

     

Numerical subarea of sensitive zone of monitoring variable of landslides to fluctuation of water level of Three Gorges Reservoir — a case of Xietan Landslide

In the period of impounding and running of the Three Gorges Reservoir, the sensitive degrees of change of groundwater table and displacement to the fluctuation of water level are different in different parts of landslides induced by the fluctuation of water level (as the case of Xietan Landslide). According to the relationship between different sensitive degrees of monitoring variables (underground water level and displacement) and quantity of monitoring information, the sensitive zones of groundwater table and displacement to the fluctuation of reservoir water level are divided into different degrees by the approach of fuzzy pattern recognition. The result of numerical subarea of sensitive zone of groundwater table and displacement indicates that the middle and front part of the landslide are the main places with groundwater table affected by the fluctuation of water level of reservoir; the variation of horizontal displacement of surficial part of the middle and front part of the landslide is more sensitive to water impounding and sudden fall of water level; and with the increase of elevation and depth of the landslide, the horizontal displacement changes less and less; the change of vertical displacement of surficial parts of the landslide is most sensitive to the fluctuation of water level of Three Gorges Reservoir; and with the increase of depth, the change of vertical displacement become smaller and smaller. By the means of the numerical subarea regulation of Xietan Landslide, the suggestions to the point layout for monitoring the groundwater table and displacement in the landside of Three Gorges Reservoir are put forward.     

珊瑚砂岩土力学特性分析

结合工程勘察实践及现场载荷试验成果,提出将珊瑚砂分为海洋类珊瑚砂和濒海类珊瑚砂两大类,并在此基础上对珊瑚砂进行了规范定名,通过现场载荷试验对各类珊瑚砂的岩土力学特性进行了研究分析,阐明了各类珊瑚砂的岩土力学特性,对今后进一步研究珊瑚砂的岩土力学特性及工程实践具有一定指导意义.     

A review of theories of mechanisms of induced seismicity

Theories of the physical processes leading to the stimulation of seismic activity by underground explosions, fluid injection, and reservoir impoundment are summarized. In all cases, the materials must be pre-stressed to a substantial fraction of their breaking strength in order for seismicity to be induced. Stress concentrations due to the presence of old faults or to inhomogeneities in the material properties play an important role in localizing induced seismicity.

For the few cases for which data are available, the stimulation of earthquakes by fluid injection in bore holes is adequately explained by a Coulomb-Mohr failure criterion and the concept of effective pressure in a water-filled porous mechanism. Reservoir-related earthquakes are most likely due to the same mechanism, but, in view of the low injection pressures, additional physical or chemical effects of the water on the materials may play an important role. There may be a weakening of the materials in old fault zones by the introduction of water or static fatigue in silicate rocks due to stress corrosion.