长江三角洲环境地质调查评价GIS管理系统建设初探

长江三角洲是一个人口稠密、经济高度发达的地区 ,该区地质结构复杂、环境地质条件十分脆弱 ,长期以来因过量开采地下水 ,形成大面积区域性水位降落漏斗 ,诱发了相当严重的地面沉降、地裂缝等地质灾害 ,给当地经济可持续发展带来严重威胁。本文从开展长江三角洲环境地质调查评价的现实意义出发 ,探讨了长江三角洲环境地质调查评价GIS管理系统的系统目标、开发模式以及实现步骤 ,概括介绍了系统所应具有的功能 ,为长江三角洲项目信息系统建设提出了一条可行性思路。     

准噶尔盆地西北缘侏罗系储层

准噶尔盆地西北缘侏罗系陆相碎屑岩储层的岩性差异较大，岩性对物性的控制作用明显。储层的孔隙类型多样，不同类型的孔隙在发育规模、丰度及有效性方面都存在显差异，次生溶蚀孔隙、原生粒间孔隙和残余粒间孔隙是最重要的有效孔隙类型。储层渗透率与孔隙度之间存在较好的半对数相关关系。通过设置一定的孔隙度和渗透率参数界线，对储层储集性能进行评价，将侏罗系储层的孔渗性能划分为5个级别，可与当前流行的砂岩储层孔渗性能分级相对应。通过对大量压汞参数样本的聚类分析，将储层的孔隙结构划分为4个类型。通过各类参数统计及曲线形态对比，对孔隙结构类型进行了定量结合定性的优劣评价。最后，结合孔渗性能级别、储集空间类型、孔隙结构类型、岩性等特征，对准噶尔盆地西北缘侏罗系储层进行了综合分类评价。     

Numerical evaluation of the damping‐solvent extraction method in the frequency domain

The damping‐solvent extraction method for the analysis of unbounded visco‐elastic media is evaluated numerically in the frequency domain in order to investigate the influence of the computational parameters—domain size, amount of artificial damping, and mesh density—on the accuracy of results. An analytical estimate of this influence is presented, and specific questions regarding the influence of the parameters on the results are answered using the analytical estimate and numerical results for two classical problems: the rigid strip and rigid disc footings on a visco‐elastic half‐space with constant hysteretic material damping. As the domain size is increased, the results become more accurate only at lower frequencies, but are essentially unaffected at higher frequencies. Choosing the domain size to ensure that the static stiffness is computed accurately leads to an unnecessarily large domain for analysis at higher frequencies. The results improve by increasing artificial damping but at a slower rate as the total (material plus artificial) damping ratio ζ_t gets closer to 0.866. However, the results do not deteriorate significantly for the larger amounts of artificial damping, suggesting that ζ_t≈0.6 is appropriate; a larger value is not likely to influence the accuracy of results. Presented results do not support the earlier suggestion that similar accuracy can be achieved by a large bounded domain with small damping or by a small domain with larger damping. Copyright © 2002 John Wiley & Sons, Ltd.     

初论古文化类型演替与传承模式的区域分异——以西拉沐沦河流域和汶泗流域为例

西拉沐沦河流域地处中国地貌大势三大台阶之中台阶与低台阶的过渡区。该区的中度抬升和下切,造成了西拉沐沦河流域考古文化遗址在空间上的垂向迁移;频繁的迁移也导致了考古遗址在堆积形态上主要表现为单一型,体现了不同考古文化之间“间断”的,不稳定的传承方式。位于中国地貌大势之低台阶上的汶泗流域,属自下古生代以来就十分稳定的剥蚀区,这些自然条件造成了汶泗流域遗址在堆积形态上主要表现为叠置型,考古文化在时空上,很少随着时间做空间上的改变,基本上在同一水平空间稳定不动,体现了不同考古文化之间“连续”、稳定的传承方式。两个流域的对比研究说明,不同地域、不同的自然条件,可以造成考古文化演替与传承模式的区域分异     

中国区域成矿研究的若干问题及其与陆-陆碰撞的关系

在中国区域成矿作用研究中 ,遇到诸多重大问题 ,如 :(1)中国东部属于环太平洋地区之一 ,但为什么热液矿床大规模成矿时代不同于环太平洋的新生代 ,而爆发于中生代的燕山期 ?(2 )中国陆区经历了 >3.0Ga的演化 ,为什么大规模成矿作用在东部地区爆发于燕山期 ,西南特提斯成矿域爆发于新生代 ,而西北中亚成矿域爆发于海西期晚期 ?(3)国外不少著名成矿省位于太古宙克拉通内部 ,为什么中国的有色贵金属等热液矿床却集中分布于显生宙造山带内部或其边缘 ?(4)按照绿岩带金矿成矿理论 ,绿岩带型金矿化伴随或尾随于克拉通化 ,形成在太古宙 ,为什么中国绿岩带型金矿却形成在克拉通化后的 2 0多亿年以后的中生代 ?(5 )世界范围内 ,海相油田的重要性远大于陆相 ,为什么中国情况恰相反 ,陆相油田远比海相油藏重要 ?……。笔者认为这些问题彼此相关 ,代表了中国区域成矿的特色 ,其根本原因在于中国陆区不同构造单元经历了晚古生代以来的强烈碰撞事件 ,因此加强研究碰撞造山体制的成岩、成矿、成藏和流体作用是解决这些问题的关键途径。     

区域水资源开发模式研究

正确的不资源开发模式对于指导合理开发利用区域水资源并最大限度降低环境生态负效应具有重要的意义。以松嫩盆地为例，根据研究区内的水文、水文地质条件，应用模糊集理论与方法确定出松嫩盆地各县市的水资源开发模式，并对各种开发模式做了简要论述。     

Evaluation of the Reduction in Uncertainty Obtained by Conditioning a 3D Stochastic Channel to Multiwell Pressure Data

A stochastic channel embedded in a background facies is conditioned to data observed at wells. The background facies is a fixed rectangular box. The model parameters consist of geometric parameters that describe the shape, size, and location of the channel, and permeability and porosity in the channel and nonchannel facies. We extend methodology previously developed to condition a stochastic channel to well-test pressure data, and well observations of the channel thickness and the depth of the top of the channel. The main objective of this work is to characterize the reduction in uncertainty in channel model parameters and predicted reservoir performance that can be achieved by conditioning to well-test pressure data at one or more wells. Multiple conditional realizations of the geometric parameters and rock properties are generated to evaluate the uncertainty in model parameters. The ensemble of predictions of reservoir performance generated from the suite of realizations provides a Monte Carlo estimate of the uncertainty in future performance predictions. In addition, we provide some insight on how prior variances, data measurement errors, and sensitivity coefficients interact to determine the reduction in model parameters obtained by conditioning to pressure data and examine the value of active and observation well data in resolving model parameters.     

基于GIS的区域地质调查数字制图--以1∶5万<里庄幅>为例

本文以 1∶5万里庄幅为例 ,阐述了运用GIS系统对区调过程中各种资料的处理与编辑方法 ,并介绍了数字制图方法及工艺流程 ,提出了GIS系统在 1∶5万区调工作中的应用前景     

MODIFIED MASS FLUX CUMULUS CONVECTIVE PARAMETERIZATION SCHEME AND ITS SIMULATION EXPERIMENT—PART Ⅰ:MASS FLUX SCHEME AND ITS SIMULATION OF THE 1991 FLOOD EVENT*

Based on the existing cumulus convective parameterization schemes,a mass flux scheme (MFS) for cumulus convective parameterization has been successfully developed by reference to the work of Chen et al. (1996).The MFS is a comprehensive scheme.In MFS,not only the importance of the large-scale moisture convergence is taken into account,but also it includes the cumulus updrafts and downdrafts,cumulus-induced subsidence in the environmental air.entrainment,detrainment and evaporation.The interaction between the cumulus and the environment is described by using a one-dimensional bulk model.At the same time the scheme includes the penetrative and shallow convections.The MFS has been successfully incorporated into the regional climate model RegCM2 developed by NCAR.The new model has been applied to simulate summer monsoon characteristics and their variations of heavy rainfall process in the Changjiang-Huaihe River Basins for three months from May to July 1991.The results show that the new model can successfully simulate this rainfall prolonged process.By comparising the model outputs of RegCM2.using the Kuo scheme and the MFS.it is found that the MFS is better in simulating the surface temperature,rainfall position and amount,and rainfall duration.     

Seismic evaluation of existing nuclear facility using ambient vibration test to characterize dynamic behavior of the structure and microtremor measurements to characterize the soil: a case study

The methods used for a building seismic hazard evaluation are presented with the associated results. The goals of the study are (1) to check the soil nature and the existence or not of a possible site effect around the installation and (2) to characterize the dynamic behavior of the building using ambient vibration records.

The results of the soil study with the Nakamura method are very difficult to interpret because they are not stable in space and time. The spectral ratios method has been used with regional earthquake records. The results of the application of this method allowed us to conclude that the installation was free of site effect.

The ambient vibration measurements on the building brought the conclusion to determine the first and second modes of the structure. These results have been used to calibrate numerical model. The modal shapes in plan (high roof) and in elevation (main column) have been evaluated. The damping of the building has been computed using ambient vibration records.