跨孔地震CT在类岩溶地层中的应用效果分析

类岩溶地层的溶蚀结构十分复杂,对岩体的稳定性、强度等均有不良影响,探明类岩溶的溶蚀结构对工程建筑安全十分必要。以我国西南某拦河闸的右岸交通桥勘察为例,对比分析跨孔地震CT与传统钻探勘察方法在钙质砾岩中应用效果的差异性。研究表明跨孔地震CT虽在精细岩溶探测方面还存在一定不足,但能够较清晰的显示类岩溶地层岩壁、基覆界线等边界轮廓,在总体地质条件探测、优化勘探工作量、节省投资、加快工期等方面具有一定优势。研究成果可对跨孔地震CT在类岩溶的应用效果及应用价值提供依据和参考。

水库坝址区类岩溶发育特征及溶蚀试验研究

坝址区在水库蓄水期间出现渗漏后,会导致水电站的收益降低,严重时还可能诱发安全事故。鉴于坝址区岩溶环境十分复杂,尤其是钙质砂岩,其在酸性环境作用下,钙质胶结物发生化学溶解,出现类岩溶现象。钙质砂岩发生溶解后,岩石的强度和渗透性发生改变,影响坝址区的安全。基于国内外研究现状,首先分析了坝址区的类岩溶类型和钙质砂岩、钙质砾岩的溶蚀特征,随后对坝址区钙质砂岩、钙质砾岩进行溶蚀试验研究,得出了不同岩质的钙离子、电导率、溶蚀率变化。最后基于试验结果,对溶蚀机理进行讨论。

四川盆地含膏盐红层特征及坝基工程地质问题(Ⅰ)

以四川盆地含膏盐(石膏、芒硝、钙芒硝)红层为例,论述了含膏盐红层的沉积环境及其分布范围,膏盐矿物在红层岩体中的分布及其矿物学特征,讨论了由于膏盐矿物溶蚀形成的有别于常规碳酸盐岩岩溶作用的红层类岩溶作用。依据水电工程实例,描述了红层坝基类岩溶形态,分析了类岩溶和溶蚀下限机理,同时给出了四川盆地几各水电工程类岩溶红层坝基的溶蚀下限深度,为确定坝基岩体防渗深度提出了相关地质依据。

四川盆地含膏盐红层特征及坝基工程地质问题(Ⅱ)

本文探讨了四川盆地含膏盐红层类岩溶作用引起的坝基工程地质问题,首先是地下水化学成分的改变及其对水工结构混凝土的腐蚀作用及坝基渗漏问题,然后确定了表征类岩溶作用强度的类岩溶强度因子(k)。最后,通过类岩溶岩体Vp与主要岩体工程力学指标,诸如:允许承载力fak、抗剪(断)摩擦系数f(f′)、变形模量(E0)的回归关系,探讨了类岩溶作用对坝基岩体弱化的作用。

基于未确知测度理论的煤层底板突水危险性评价

运用未确知测度理论,建立煤矿奥灰岩岩溶水类底板突水评价模型。选取煤层底板的地质构造(断裂构造密度、褶皱、断层导水性、岩体的裂隙发育情况)、水文地质条件(水压、含水性、岩溶含水层发育情况、强水源补给情况)、底板隔水层条件(隔水层厚度、岩石力学强度以及隔水岩层的完整性)、开采条件(采厚和采深)4个一级指标、13项二级指标作为未确知测度模型的判别指标;根据指标值的类型采用定量或定性的方法对其进行分级和赋值,建立评判集,进而构建单指标测度函数。将13个突水评价指标值代入单指标测度函数计算得到单指标测度评价矩阵。利用信息熵理论获得各判别指标的权重,依照置信度识别准则进行等级判定,最后得出煤层底板突水危险性评价结果。利用该方法对肥城矿区14个地质块段的煤层底板突水危险性进行评价,结果表明,该评价结果与矿山实际情况相符。

陕西千家坪钒矿ZK5201水文地质钻孔抽水试验

千家坪钒矿在水文地质单元属于丹江支流耀岭河流域,耀岭河自西向东从矿区北部流过,矿体位于其南侧山坡上。区内地下水类型,按赋存条件可以划分为第四系松散岩类孔隙潜水、裂隙水和碳酸岩类裂隙岩溶水三种类型。碳酸盐岩裂隙溶水广泛分布于工作区,是未来矿山主要充水水源及通道,特别是矿体上盘的白云岩,岩溶水受非可溶岩的阻隔,被储存富集起来,可形成富水地段。为了查明该层水文地质条件及参数设计施工了ZK5201钻孔,该孔终孔静水位高出地表21 m,自流涌水量达20.25 m3/h,在我国北方矿山罕见。本文详细说明了该孔设计、施工、抽水试验过程及综合成果。

Human Driving Forces:Analysis of Rocky Desertification in Karst Region in Guanling County,Guizhou Province

Karst rocky desertification is one of the major ecological and environmental problems that threaten the sustainable development of southwestern China. It is caused by irrational and intensive land-use patterns in karst geo-ecological environment. Therefore, it is vital to identify how human forces work on this degraded environment. Based on the soil erosion information in 2000 and remote sensing images of Guanling County collected in 2000 and 2007, four grades of karst rocky desertification data in 14 villages of Guanling County were extracted. Impacts of population, affluence, and other human forces on karst rocky desertification were analyzed using STIRPAT model. The results show that:1) Factors of population and affluence had strong influence on karst rocky desertification. In the STIRPAT model analysis, the population and affluence coefficients were positive, indicating that the increase in population and affluence would lead to more serious desertification. 2) Factors of farmer correlated with karst rocky desertification negatively, especially the way of viewing the relationship between people and nature, and the level of knowledge about rocky desertification. Government behavior was not a significant factor in this analysis. 3) The findings provide evidence that STIRPAT model can be used to analyze the relationship between human driving forces and rocky desertification.

Mine rocky desertification： Another type of rocky desertification coexisting with Karst rocky desertification in Karst region

Mine rocky desertification is another type of rocky desertification which coexists with Karst rocky desertification, suggested firstly by professor SONG Jian-bo, Guizhou University. Mine rocky desertification is a process and result that the earth＇s surface is similar to desert landscapes after rock is exposed gradually, owing to mine wastes discharged at will which consist of waste residue, waste liquid and waste gas. On the basis of introducing Karst rocky desertification simply, we clarify the concept of Mine rocky desertification systemically, analyze its danger and compare the differences between Mine rocky desertification and Karst rocky desertification. Finally, we make preliminary discussion on the study significance of comprehensive treatment of Mine rocky desertification