Karst Hazard Assessment of Eastern Saudi Arabia

Karst phenomena exist in areas in the eastern part of Saudi Arabia, forming solution features such as sinkholes, collapsed dolines and solution caverns, as a result of the chemical leaching of the carbonate and evaporite formations by percolating water. The instability of these karst phenomena could produce land subsidence problems. This paper reviews the geology of documented karstic rock units in Saudi Arabia and proposes a simple engineering classification of the solution features characteristic of limestone. Two case histories in the Dhahran area, eastern Saudi Arabia, will be used as examples for the application of a modified engineering classification.     

不同岩溶动力系统的碳稳定同位素和地球化学特征及其意义——以我国几个典型岩溶地区为例

结合水化学的野外观测及室内计算,作者对桂林岩溶试验场、四川黄龙风景区和贵州乌江渡坝区3个岩溶动力系统的碳稳定同位素特征进行了分析,进而对系统的性质、系统中CO_2的来源、碳酸盐沉积过程中的碳同位素动力分馏、水化学和钙华的成因及热水钙华的~(14)C测年等地球化学问题作了探讨。结果表明,桂林岩溶试验场属于表层岩溶作用动力系统,其中的侵蚀动力主要来源于大气降水溶解土壤中的CO_2;四川黄龙风景区属于深部岩溶动力系统,侵蚀动力来自大气降水溶解幔源的CO_2;贵州乌江渡坝区岩溶系统,虽然属于表层岩溶动力系统,但其中一部分的同位素和水化学特征已受到人类活动的重大影响。     

物探方法在岩溶勘查中的应用综述

简要介绍了岩溶勘察中常用物探方法的基本原理和技术，并举例说明其在岩溶地区进行水利水电工程地质勘察、岩溶地下水寻找、环境保护和溶洞探测时的有效性。     

宁南深层岩溶地下水系统三维数值模拟

宁南“南北古脊梁”岩溶裂隙水系统的储水空间以岩溶裂隙为主,岩溶水的空间分布明显受南北向大型断裂构造控制。根据水动力场和水化学场特征,划分了3个相对独立的岩溶水子系统。通过三维数值模拟计算,确定了马渠—洪河岩溶水子系统天然资源量和可开采资源量,为本区的地下水合理开发利用提供了科学依据。     

大同煤田岩溶地下水的水文地质特征分析

根据大同煤田岩溶地下水化学特征资料、钻孔揭露岩溶发育的资料、以及矿井出水资料，结合岩溶地下水区域水文地质条件、岩溶地下水的水温与同位素特征，对大同煤田岩溶地下水的富水层位与找水方向作了进一步的探讨与分析。     

Dynamik der Schilfröhrichte am Bodensee unter dem Einfluss von Wasserstandsvariationen

On the basis of different sets of aerial photos the dynamics of the reed bed areas of Lake Constance were investigated in relation to the dynamics of the water levels. The objectives of the study were to quantify the changes of reed areas due to different flood events in the last decades and their recovery in the time periods between these events. The results should given information of the relevance of water level variations on reed bed dynamics and the regeneration times of reed beds after extreme disturbance events.Following the extreme flood at Lake Constance in 1999 the reed belts of Lake Constance lost approximately 30 ha (24%) of the lakeside reed beds. The loss is comparable to the situation in the late 1960s, when approximately 40 ha died back due to the extreme flood in 1965 and the high spring water levels in the subsequent years. In the time period between the extreme floods of 1965 and 1999, the reed areas expanded to nearly 85% of the area before 1965. The expansion rates increased with increasing distance to the flood event of 1965. Especially in periods with series of years of low spring water level the expansion rates were high.The damage degrees of the reed areas in the years 2000 and 2002 showed a clear relation to the elevation (i.e. average water level) of the stands. The damage degree increased with decreasing elevation. Furthermore the regeneration process of severely damaged stands was related to the elevation level of the stands. Whereas stands at high elevation regenerate fast, those at low elevation died off completely in the years after the extreme flood. This supports the hypothesis that the water level flutuations play a major role in the reed dynamics of Lake Constance.As a consequence of the climate change an increase in the frequency of high spring water levels is expected. Thus, it seems unlikely that reed stands will ever expand again to the same area as before 1965.     

植被变化对辽西夏季气候影响的数值试验

利用2001年6、7、8月份的资料及中尺度模式MM5V3．5对当年夏季辽西生态脆弱区进行了气候模拟性能试验，模拟出植被退化和恢复后辽西地区的温度变化。试验结果表明：在辽西部分地区植被退化后，当地夏季平均温度明显升高；在部分地区植被恢复后，当地夏季平均温度降低；在下垫面状况改变的周边地区，平均温度有一定程度的变化。同时，植被状况的改变对高空气压场和温度场也产生一定影响。     

电法在探测岩溶上的应用

通过对电法中几种常用方法的分析，说明其在岩溶探测中有效，并提出了七种确定岩溶的方法。     

洪山泉流量动态系统分析

为查明洪山泉域的开采程度,在前人研究基础上,建立了现阶段泉流量-降雨量的线性模拟模型。通过对模型的系统辨识,对系统的"慢时变"现象作出了合理解释,并发现系统在1994年以后发生了"快时变",说明开采量从1995年开始迅猛增加。同时,由多年来泉流量序列的自相关分析,发现其宏观周期到2000年基本保持不变,说明虽然第二输入(即人为开采量)对该系统的作用已不可忽略,但尚未达到足以改变其宏观频率的程度。     

疏降地下水引起地面塌陷浅析--以淮南煤矿区为例

以淮南西部矿区为例，介绍了该地区自20世纪60年代开采煤矿以来，由于疏降地下水，引起的地面塌陷。为了研究灰岩水动力场规律，先后在该区进行多时段、多水平放水试验。研究表明，覆盖粘土层、岩溶及人工疏降地下水，是该地区岩溶塌陷形成的基本条件。通过对粘土盖层性质、疏降地下水岩溶塌陷演化过程及塌陷机理与对应阶段过程综合分析，结合区域地质条件，掌握了塌陷点的分布规律。对目前西部地区塌陷“复活”、整治及未来城市规划，提出了建设性建议。