文昌B凹陷陡坡带珠海组二段海侵扇三角洲储层特征及油气成藏特征

利用构造、层序地层、沉积古地貌、沉积微相分析、成藏综合分析等方法,对珠江口盆地文昌B凹陷陡坡带特殊构造背景下的珠海组储层沉积相及其油气成藏模式进行研究,认为该区珠海组二段与珠海组一段构成了一套优质区域性储盖组合,珠海组二段沉积期,在陡坡带古丘地貌上发育潮控海侵退积型扇三角洲相,其水下分流河道骨架砂岩较好的孔渗性使珠海组二段成为油气优势运聚成藏层系,是主要勘探目的层之一。结合烃源岩、沟源断裂及圈闭等成藏主控因素分析,提出该区珠海组二段垂向运移、优势聚集、有效断块的油气成藏模式,钻探发现文昌B凹陷陡坡带X构造整装规模储量的商业性油田和一批含油构造。     

AMS ^14C测年揭示的渤海湾沿海低地第Ⅱ海相层年龄

在渤海湾沿海低地地区获得4个机械钻孔,结合AMS 14C测年方法,对Ⅱ海的年龄进行了研究。结果显示,在Ⅱ海所在层位获得的14C样品年龄均大于43.5ka BP,说明渤海湾沿海低地地区Ⅱ海形成于MIS 3早期或MIS 5,而不是前人认为的23-39ka。建议在前人地层结构研究成果的基础上,系统开展Ⅱ海年龄研究。     

短小芽孢杆菌-蒙脱石相互作用实验研究

主要探讨短小芽孢杆菌与钙基蒙脱石相互作用过程中的现象及机理。SEM结果显示,大量土壤菌黏附、包裹于蒙脱石表面。加入蒙脱石后,短小芽孢杆菌-钙基蒙脱体系中有机酸含量明显降低。XRD结果表明,短小芽孢杆菌作用后蒙脱石层间距增大,001面衍射峰钝化。FTIR显示作用后蒙脱石出现了来自于土壤菌的新峰,其他基团峰出现蓝移或红移现象。经二阶导数红外光谱分析验证,蒙脱石中确实出现了来自于土壤菌的其他基团振动,揭示土壤菌代谢产物进入蒙脱石层间域内的初步可能性,这将为矿物-微生物相互作用间的机理研究提供新依据。     

浅谈基于InSAR的南票煤矿开采沉陷区沉降量外业检核

经过时间序列InSAR技术处理后,得到监测时间段内南票区的地面形变平均速率、累计形变量、时间序列形变量,确定沉降区域。本文通过南票煤矿开采沉陷区基岩点、基本水准点、监测点布设以及这些点测量工作,提出山区采用水准测量和GPS测量联合方法,实现沉陷区沉降量核查。     

地理国情普查数据与国土二调数据的对比分析

第一次地理国情普查在全国范围内如火如荼地进行着,其数据的科学性、准确性和实用性一直受到相关行业的关注。本文对某市的地理国情普查成果数据与国土二调成果数据进行了对比分析,验证了地理国情普查数据的科学性和有效性,为下一步地理国情普查中数据时点核准提供了参考意见。     

东营凹陷王46井孔二段暗色泥岩沉积环境

利用薄片、X衍射、微量元素、孢粉及有机地球化学等分析手段对王46井岩心进行了岩性、古生物及地球化学等相标志研究,认为该段暗色泥岩为湖盆近边缘相产物,沉积期气候暖热湿润,水质微咸淡水。     

延安城市供水二期工程水源地选区方略

通过对延安市城区及临近地区水资源与水文地质条件分析,排除了就近在这些地区再新建水源地的可能性,接着从延安市所辖县区范围内的水文地质条件出发,在原有1∶20万水文地质普查资料的基础上,确定了未来供水含水层选用白垩系洛河组潜水、承压水及第四系潜水。在分析比较区内的白垩系、第四系富水地段之后,概略计算了这些地段的地下水补给量,并从中选出3个富水地段,拟在此3个富水地段开展水文地质详查工作,作为寻找地下水源的重点工作区。     

Diffuse instabilities with transition to localization in loose granular materials

This paper is concerned with diffuse and other ensuing failure modes in geomaterials when tested under homogeneous states of shearing in various loading programs and drainage conditions. Material instability is indeed the basic property that accounts for the instability of an initially homogeneous deformation field leading to diffuse failure and strain localization in geomaterials. The former is normally characterized by a runaway type of failure accompanied with a sudden and violent collapse of the material in the absence of any localization phenomena. Against this backdrop, we present a brief overview of material instability in elastoplastic solids where one finds a rich source of theoretical concepts including bifurcation, strain localization, diffuse failure and second‐order work, as well as a considerable body of experiments. Some compelling laboratory experimental studies of material instability with focus to diffuse failure are then presented and interpreted based on the second‐order work. Finally, various material instability analyses using an elastoplastic constitutive and a general finite element analysis of the above‐mentioned laboratory experimental tests are presented as a boundary value problem. It is shown that instability can be captured from otherwise uniform stress, density and hydraulic states, whereas uniform deviatoric loads are being applied on the external boundaries of a specimen. Although the numerical simulations reproduce well the laboratory experimental results, they also highlight the hierarchy of failure modes where localization phenomena emerge in the post‐bifurcation regime as a result of a degradation of homogeneity starting from a diffuse mode signalled by a zero second‐order work. Copyright © 2012 John Wiley & Sons, Ltd.     

Bifurcation modeling in geomaterials: From the second‐order work criterion to spectral analyses

The present paper investigates bifurcation analysis based on the second‐order work criterion, in the framework of rate‐independent constitutive models and rate‐independent boundary‐value problems. The approach applies mainly to nonassociated materials such as soils, rocks, and concretes. The bifurcation analysis usually performed at the material point level is extended to quasi‐static boundary‐value problems, by considering the stiffness matrix arising from finite element discretization. Lyapunov's definition of stability (Annales de la faculté des sciences de Toulouse 1907; 9 :203–274), as well as definitions of bifurcation criteria (Rice's localization criterion (Theoretical and Applied Mechanics. Fourteenth IUTAM Congress, Amsterdam, 1976; 207–220) and the plasticity limit criterion are revived in order to clarify the application field of the second‐order work criterion and to contrast these criteria. The first part of this paper analyses the second‐order work criterion at the material point level. The bifurcation domain is presented in the 3D stress space as well as 3D cones of unstable loading directions for an incrementally nonlinear constitutive model. The relevance of this criterion, when the nonlinear constitutive model is expressed in the classical form (dσ = Mdε) or in the dual form (dε = Ndσ), is discussed. In the second part, the analysis is extended to the boundary‐value problems in quasi‐static conditions. Nonlinear finite element computations are performed and the global tangent stiffness matrix is analyzed. For several examples, the eigenvector associated with the first vanishing eigenvalue of the symmetrical part of the stiffness matrix gives an accurate estimation of the failure mode in the homogeneous and nonhomogeneous boundary‐value problem. Copyright © 2008 John Wiley & Sons, Ltd.     

CISK,EVAPORATION-WIND FEEDBACK MECHANISM AND 30—60 DAY OSCILLATIONS IN THE TROPICAL ATMOSPHERE

A baroclinic semi-geostrophic model with evaporation-wind feedback mechanism(EWFM)and CISK is established,two non-dimensional parameters a and η are introduced to representEWFM and CISK,respectively.Analytic solutions of the model system are obtained,dynamicsanalyses and the model atmosphere calculations further confirm that EWFM and CISK are veryimportant physical processes in leading to the low-frequency oscillations in the tropics.