THREE-DIMENSIONAL GEO-MORPHOLOGICAL MODELLING OF ESTUARINE WATERS

1 INTRODUCTION Estuaries and coastal zones have been used as means of navigation, disposal of waste material, fishing and many commercial and economic activities over the centuries. One of the most important phenomena in these regions is the suspended sediment transport, which may cause erosion and deposition, and hence changes in the estuarys morphology. In turn, such changes may lead to problems relating to navigation and estuarine management. When the bed boundary of an estuary change…     

地下钻杆透层天线

对于有耗分层媒质中的垂直透层天线，建立了Ｈａｌｌｅｎ积分方程分析法的一般理论以及求取地面电场和电压的计算方法．作为应用实例，给出了地下３层媒质中钻杆天线上的电流积分方程，并对典型的地质参数进行了数值计算．所得结果和结论，与已知的理论结果和实验规律吻合。     

TEMPERATURE ANOMALIES OVER UNDERGROUND CAVITIES*

Theoretical and practical aspects of a new method for underground cavity localization are presented. The method is based on shallow temperature measurements. It is shown that such measurements can complement the geophysical methods most commonly used for cavity location. The results from finite-difference numerical calculations indicate possible origins of temperature anomalies–the existence of which is confirmed experimentally, primarily by field measurements. Temperature anomalies up to 1°C have been recorded over underground cavities. A satisfactory agreement between measurements and theory is found.     

RECENT DEVELOPMENTS IN UNDERGROUND GRAVITY SURVEYS1

Underground gravity observations in deep coal mines using the conventional gravity meters Worden (type Master) and LaCoste-Romberg (model D), both of which have been adapted to the fire damp regulations, can be accurate to ± 10 and ± 3 μgal, respectively. For underground determination of the vertical gradient of gravity the LaCoste-Romberg meter is used together with a specially designed measuring tower. Using this euipment an accuracy in tower gradient observations of ± 30 E was obtained. To apply the equipment to precision gravity observations in underground situations an additional correction, i.e. a gallery correction, is needed. High accuracy in correction is achieved by a new method of three-dimensional modelling. The gravity effect is computed for bodies with a surface approximated by triangular elements, which are generated from corner points of the body. The combination of gallery correction with tower gradient data leads to a new method for in situ density determination. It offers the possibility of horizontal instead of vertical density profiling. To demonstrate the effectiveness of the developments in underground observations the localization of a pump room is presented. Microgravity and tower gradient observations were carried out to detect the cavity. The horizontal gradient was also calculated to give a more reliable location.     

腾冲热海地下流体观测研究

指出前人在研究腾冲地热时的工作模式及其工３作结果,大多数只能反映腾冲水热活动区的静态特征和横向特征。同时提出：在腾冲热海开展地下流体观测的目的,就是通过对与现代幔源岩浆活动相关的热海水热显示区内部分泉点进行长期的连续观测,发现热海地下流体动态变化规律,预测热海热田的发展趋势。通过观测研究得出：⑴热海地区的地热海支处于不断变化之中,这种变化可能和该区的地下帽源物质活动有关;⑵热海热田自１９９３年以来     

MEASUREMENTS OF TURBULENT DIFFUSION IN ESTUARINE AND INSHORE WATERS

Abstract

A new tracer technique for the direct observation of movement and dispersion of estuarine and inshore waters is described. The method utilizes the fluorescent organic pigment, rhodamine B, together with a very stable, compact filter fluorometer. The tracer is very satisfactory with regard to stability, cost, toxicity, and detectability. Its nearly unique fluorescent and absorption spectra minimize the effect of natural background so that concentrations as low as 2 × 10^?11 have been observed in the field, with expectations that this detection limit can be lowered to 4 × 10^?12. Advection and diffusion from approximate point sources discharged in Baltimore Harbor, in Conowingo Lake, and in Chesapeake Bay were measured. Theoretical models of horizontal diffusion are compared to the observed decrease in concentration with time.     

UNDERGROUND GRAVITY SURVEY IN ALPINE REGIONS*

An underground gravity study was carried out under extreme conditions of the Alpine regions. The lead–zinc mine Bleiberg, Carinthia, was selected as an example to show the possibilities and limitations of the subsurface gravity method. For in situ density determinations, gravity measurements were made in two vertical mine shafts passing through Triassic sedimentary rocks of the Bleiberg Unit. The main prblem in gravity data reduction in extremely rugged topography is the accurate calculation of the terrain effect on underground stations. A general discussion of the various corrections required for the gravity measurements in the mine is presented. The mean interval densities in the two shafts, in limestone, dolomite, and schists formations, were determined as 2.76 and 2.77 g/cm³, respectively, with an accuracy of better than 0.01 g/cm³ for a depth interval of 50 m. The interval densities provide valuable information about the lithological and structural changes in the shaft surroundings and also agree well with the representative hand sample densities. In the second part, the applications of subsurface horizontal gravity surveys in exploration are discussed. Since the influence of topography is less underground because of the greater distance to the surface, subsurface surveys have definite advantages over surface surveys and can be very helpful in locating anomalous density zones in the mines. An example of gravity survey with a station spacing of 10 m at a depth of about 540 m is presented.     

高密度电法探测地下空洞

简要介绍了高密度电法的基本原理及其特点,结合探查地下空洞实例,说明高密度电法寻找地下空洞的利弊。     

丹东地区地下水位微动态信息初探

丹东地区现有四口地下水位观测井,分别是东港汤池井、四道沟滨江井、同兴乡变电井、宽甸明安井。本文利用多年的观测资料对这四口井进行了对比分析,着重分析了气压、降雨对地下水位的影响,从前震效应、震后效应、同震响应方面对四口井加以分析,找出了四口观测井的微动态信息,并对丹东地区地下水井点的分布及所反应的微动态信息优劣进行了对比...     

地下结构工程抗震分析方法综述

我国地下结构工程发展很快,但其抗震分析的研究还存在着亟待解决的问题。本文简单说明了地下结构工程抗震发展历史和地震反应的特点,并详细介绍了地下结构抗震分析方法的三种分类,以及具体方法的原理,以此加深人们对地下结构工程抗震分析方法的认识,引起人们对地下结构工程抗震的重视。     

地下核爆近场局部地形效应

讨论了在＂８７０３＂工程中地形局部效应强震台阵的记录结果，认为地形差异引起的地面运动参数的放大和频谱特征的变化是使震害（感）加大的重要原因，并对产生的原因做了讨论。     

近海海面对大气运动响应的数值研究

本文采用数值方法模拟近海对海面风场、气压场变化的响应。试验和比较了不同天气形势下黄海、东海海域水位变化过程,并讨论了不同因子的作用和有关数值方法问题。为在我国现有计算条件下,开展风暴潮数值预报提供有益的参考。     

沈阳市地下管道震害预测工作

本文根据规范给出的地下管道分析模型,并采用随机动力可靠性分析方法,对地震波作用下的管道进行简化计算,对沈阳市地下管道进行分析预测,并给出在不同地震作用下的预测结果。     

近海海面对大气运动响应的数值研究

本文采用数值方法模拟近海对海面风场、气压场变化的响应。试验和比较了不同天气形势下黄海、东海海域水位变化过程,并讨论了不同因子的作用和有关数值方法问题。为在我国现有计算条件下,开展风暴潮数值预报提供有益的参考。