刚臂式单点系泊系统在波浪作用下的链力分析

第一个刚臂式单点系泊储油装置(SBS)于1974年在突尼斯建成,以后在各地又建成了很多个这类装置,据报导其使用效果是令人满意的[1,2].为了发展我国海洋石油勘探、开发的科学技术,在海洋石油研究所的协助下,我们对这种系泊系统进行了波浪模型试验研究,本文在试验成果的基础上,主要研究单点浮筒多链系统的静力特性和波浪要素、水深等对链力的影响,还研究了减小中链力的措施.     

Application of homotopy parameter inversion method in Miyun Reservoir

The large-scale convergence of homotopy parametric inversion method on the water quality model parameters calculated was used, with application in parametric inversion calculation of total phosphorus of Beijing Miyun Reservoir. Through calculated and compared the error of sedimentation rate by homotopy parametric in- version method and genetic inversion calculation method, the results indicate that homotopy parametric inversion method has good stability, calculating speed, and even if the initial selection away from the objective function, the solution still has a good convergence.     

Study of elastic-plastic damage model of cement consolidated soil with high organic content

On the basis of elastic-plastic damage model of cement consolidated soil, the authors took organic contents into reasonable damage variable evolution equation in order to seek relation between the organic contents and parameters in the equation, and established the elastic-plastic damage model of cement consolidated soil considering organic contents. The results show that the parameters change correspondingly with difference of the organic contents. The higher the organic contents are, the less the valves of the parameters such as elastic modulus （E）, material parameters （K, n） and damage evolution parameter （ε） become, but the larger strain damage threshold value （εd） of the sample is. Meanwhile, the calculation results obtained from established model are compared with the test data in the condition of common indoors test, which is testified with reliability.     

Experimental study on ultrasonic propagation in water-based bentonite slurry

Drilling fluid is a common flushing medium used in pile foundation, geological drilling and petroleum drilling. Study on ultrasonic propagation properties in drilling fluid is of vital importance, not only for developing equipments to non-contact measuring concrete casting level for bored pile, but also for developing equip- ments considering drilling fluid as signal channel. The existence of clay particles makes the ultrasonic propagation and attenuation in drilling fluid much different from pure water. In order to know the relation among ultrasound frequency, slun-y density and depth, a series of laboratory experiments about ultrasound propagation in water-based bentonite slurry were finished. Wavelet method was adopted to process the gained original waves of ultrasonic propagation in slurry, so we knew the velocity and attenuation coefficient of ultrasound propagated in different drilling fluids with different density. The first group experiments shows that with density of drilling fluid increase, ultrasonic velocity will decrease but attenuation coefficient will increase if ultrasonic frequency keep constant. The second group experiments shows that the power of ultrasound will intensify in small bore hole, the attenuation coefficient is much smaller than theoretical value.     

Shaking table tests and numerical simulation of dynamic properties of underground structures

It is considered thai the damage of the underground structures caused by earthquakes is minor for a long time. However, the catastrophic damages induced by several recent earthquakes （e. g. Kobe earthquake in 1995 ） revealed that the study on the dynamic properties of the underground structures is indispensable. The dynamic behavior and damage mechanism of underground structure are analyzed by using shaking table tests （ both shallow-and deep-buried） and numerical simulation （3D FEM） including horizontal and vertical input motions, individually and simultaneously. From the results, the underground structure collapsed due to strong horizontal forces although vertical deformation is not negligible. The vertical excitation increases the response of structure, especially the stress and shear stress at the upper section; the soil influenced the property of soilstructure system. In the same excitation, the response in shallow-buried test is larger than deep case. Both overburden and vertical earthquake play important roles in the response of structure and those are two critical aspects in the design of the large-span underground structures, such as subway stations.     

Permeability Heterogeneity in a Fractured Sandstone–Mudstone Rock Mass in Xiaolangdi Dam Site, Central China

Abstract: Heterogeneity of permeability in fractured media is a hot research topic in hydrogeology. Numerous approaches have been proposed to characterize heterogeneity in the last several decades. However, little attention has been paid to correlate permeability heterogeneity with geological information. In the present study, several causes of permeability heterogeneity, that is, lithology, tectonism, and depth, are identified. The unit absorption values (denoted as ω), which are results obtained from the packer test, are employed to represent permeability. The variability of permeability in sandstone–mudstone is so significant that the value of unit absorptions span 3–4 orders of magnitude at any depth with several test sections. By declustering, it has been found that under a similar tectonic history, the means of permeability differ greatly at different formations as a result of different mudrock contents. It has also been found that in the same formation, permeability can be significantly increased as a result of faulting. The well-known phenomenon, the decrease in permeability with depth, is found to be caused by the fractures in the rock mass, and the relationship between permeability and depth can be established in the form of logω–logd. After subtracting the trend of ω with absolute depth, the mean of the residual value at each relative depth can be well correlated with the distribution of mudstone. The methods proposed in this paper can be utilized to research in similar study areas.     

Aerodynamic Characteristics of the Crest with Membrane Attachment on Cretaceous Pterodactyloid Nyctosaurus

The Nyctosaurus specimen KJ1 was reconstructed under the hypothesis that there is a membrane attached to the crest;the so-called headsail crest.The aerodynamic forces and moment acting on the headsail crest were analyzed.It was shown that KJ1 might adjust the angle of the headsail crest relative to the air current as one way to generate thrust (one of the aerodynamic forces,used to overcome body drag in forward flight) and that the magnitude of the thrust and moment could vary with the gesture angle and ...     

从滇黔桂“金三角”区域地层地球化学演化特征探讨卡林型金矿的物质来源

选用滇黔桂地区东经103°～110°,北纬22°～26°,面积约20万km2,34幅1∶20万水系沉积物统计结果资料,全面系统地探讨本区及其邻近区域地层地球化学特征及其与成矿的关系。结果表明:(1)与华南地区相比,本区存在Sb、As、Au、Hg等低温元素矿集区的地球化学块体,金具有深源性,而砷、锑、汞则是区域性的高背景,本区金与砷、锑、汞的相伴,既有必然性,又有偶然性;(2)与基性岩浆活动有关的亲基性场元素、氧化物、矿化剂高背景的形成,是本区右江裂谷带、富宁—关岭南北向断裂带、文山—富宁逆冲推覆构造带,特别是峨眉地幔柱所产生的基性岩浆喷溢及火山碎屑浊流沉积的客观地球化学反映;(3)黔西南地区二叠纪峨眉山玄武岩喷发导致二叠系和三叠系金及大量亲基性场元素的突变,右江裂谷活动至少始于寒武纪,随着时间的推移,由桂西往黔西南逐渐裂开;(4)滇黔桂"金三角"地区卡林型金矿的物源与裂谷、特提斯和区域性深大断裂和峨眉地幔柱长期活动相伴的基性火成岩及火山碎屑浊流沉积有关。     

华南东段加里东期花岗岩类形成构造背景探讨

根据近年对区域地质调查取得的认识和前人的研究成果,研究了华南东段加里东期花岗岩类的地质产状、分布规律、形成时代以及Nd、Sr同位素特征;结合研究区超镁铁质-镁铁质岩及火山岩的形成时代、震旦纪—奥陶纪的沉积环境、加里东期构造事件的构造变形特征,对加里东期花岗岩类的形成背景进行了探讨。结果表明,加里东期花岗岩类形成于410～460Ma,大部分岩体属于S型花岗岩,岩浆来源于地壳物质的部分熔融;极少数为I型花岗岩,有幔源物质参与。研究区在早古生代不存在与俯冲有关的弧火山岩,也不存在大面积的早古生代I型花岗岩,震旦纪—奥陶纪地层主要形成于浅海环境。研究提出,加里东期花岗岩类主体形成于板内构造环境。     

利用数字强震仪记录实时仿真地动位移

随着现代强震仪及通讯技术的发展, 强震动观测资料的应用范围愈来愈广, 强震观测可以拓展到地震观测领域, 强震数据的实时仿真是这一拓展的基础. 为适应这一发展趋势, 在笔者曾经提出的单自由度系统地震反应递归公式的基础上, 本文提出了一套基于地震仪原理, 及长周期单自由度系统地震动力反应原理的由宽频带强震动记录仿真位移记录的新方法. 研究表明此方法是有效的, 可广泛应用于地震监测.