喀斯特岩机制砂石混凝土研究

喀斯特地貌区大面积分布被地下水溶蚀形成的岩溶石灰岩(喀斯特岩),这些岩石在以往工程中不于适用,资源极大浪费。结合某西部水利水电工程,用喀斯特岩机制砂石代替石灰岩砂石制备混凝土,并开展一系列对比试验研究。试验结果表明,喀斯特岩机制砂石混凝土的各项性能指标满足设计要求,并在实际工程中得到成功应用。该研究对于喀斯特岩机制砂石在水工混凝土中的推广应用具有重要指导意义。

喀斯特白云岩坡地土壤异质性特征与土壤保育模式研究

在"石漠化"相对较低的白云岩典型坡地上,对石质地块、石土质地块、土石地块和土质地块的土石结构、土壤厚度、土壤颗粒结构等土壤空间异质性特征进行测量分析。随着坡长与坡位的变化,样方内出现受侵蚀后搬移堆积的土壤数量增加,同时土壤厚度的变异系数由1.7降低到0.63,但是>2mm的土壤颗粒比例从13.66%增加到23.48%,土壤侵蚀致使土壤颗粒结构出现"粗粒化"趋势。结合与侵蚀环境因素的相关分析,提出不同土壤异质性特征坡地地段的土壤保育模式。

岩溶区库坝面板混凝土骨料影响因素评价体系研究

针对岩溶区抽水蓄能电站上水库库盆与主坝面板混凝土施工中存在的喀斯特岩机制砂石,应用XRD、SEM和MIP等微观分析方法研究了骨料微观特征,对骨料影响正交因素试验数据进行分析,验证了喀斯特岩机制砂石在堆石坝面板混凝土中的可用性,建立了因素评价体系,对于骨料性能与胶砂抗压强度、净浆需水量、净浆抗压强度、凝结时间和3d水化热的影响度和敏感度进行定量评价,在混凝土配合比优化设计中发挥指导作用。

西南岩溶地区地下水资源承载力空间演变及差异研究——以贵州为例

该文基于水资源生态承载力模型方法计算贵州九市、州2000-2018年地下水资源承载力和分析空间演变特征,并且用泰尔指数进行差异测度。结果表明,从行政区来看,各市、州无论地下水资源生态承载力总量或者地下水资源承载力模数变化均具有一定的波动性,并具有明显三个档次,处于第一档次的是黔东南、遵义市、毕节市和黔南州;处于第二档次的是铜仁市、黔西南;处于第三档次的是六盘水市、安顺市和贵阳市。从流域来看,贵州"两江"流域的地下水资源承载力总量和承载力模数变化也存在一定的波动性,贵州长江流域的地下水资源承载力总量的多年平均值是贵州珠江流域的2.3倍,而地下水资源承载力模数比贵州珠江流域多2.9×10^(5)hm^(2)/a。通过泰尔指数的测度表明地下水资源承载力模数整体水平差距比较小,贵州各市、州以及"两江"流域地下水资源生态承载力的年际变化都比较小,其形成机制主要是自然因素和人为因素差异的影响。

Dynamic Change and Simulation and Prediction of the Karst Rocky Desertification Sensitivity in Guizhou Province

Sensitivity evaluation of rocky desertification is to recognize the areas prone to be rock-deserted,so as to assess the sensitivity degree of rocky desertification to human activities.To perform the sensitivity evaluation of rocky desertification,we should be on the basis of the mechanism of rocky desertification formation for analyzing its regional distribution difference in the sensitivity and further for finding out the rocky desertification-susceptive areas and their possible degrees.Employing remote sensing and geological information system techniques,we regarded the 1∶ 50 000 topographic map and the TM image in 2000 of Guizhou Province,together with the hydrologic map,soil map,geologic map,rock formation map,administrative map and other geological information as data sources to generate the degree data of rocky desertification sensitivity of Guizhou Province in 1962 and 2000,based on which we determined the corresponding degree transfer matrix and adopted Markov model to simulate the dynamic change process of rocky desertification sensitivity and its future evolution trend.In various sensitivity types of rocky desertification in Guizhou Province,only the insensitive type showed a declined acreage,from the proportion of total land acreage of 61.35% in 1962 to 55.55% in 2000.Various sensitivity types inter-conversed,resultantly the acreage of mildly sensitive type increased most.The prediction results showed that the acreage of insensitive type of rocky desertification in Guizhou Province will assume a remarkable decline trend,of mildly sensitive type will present a remarkably increasing trend and of slightly sensitive type basically will maintain a stable level in the future tens of years.Acreages of both highly sensitive and extremely sensitive type of rocky desertification expanded to some extent,suggesting that the rocky desertification risk in Guizhou Province is in an aggravating process.

Prediction of Fracture-Cavity System in Carbonate Reservoir： A Case Study in the Tahe Oilfield

The carbonate rocks in Tahe oilfield, which suffered from multi-period polycycle karstification and structure deformation, are heterogeneous reservoirs that are rich in pores, cavities,and fractures. The reservoirs are diversified in scale, space configuration, and complex in filling. For this kind of reservoir, a suite of seismic prestack or poststack prediction techniques has been developed based on the separation of seismic wave fields. Through cross-verification of the estimated results,a detailed description of palaeogeomorphology and structural features such as pores, cavities, and fractures in unaka has been achieved, the understanding of the spatial distribution of reservoir improved.

Karst Cave Tourism System in Zhejiang Province Based on Resource Regional Analysis

Karst cave tourism plays an important role in the overall tourism of Zhejiang Province, China. In analyzing the current status of karst cave tourism resources, it is crucial to develop a scientific system for optimizing resource exploitation and tourism development in the future. This study conducted an analysis of resource characteristics and regional structure in Zhejiang Province. Nearest neighbor index （NNI） method and accessibility index method were used for a comprehensive understanding of the effects of scale, strength, combination, and accessibility of karst cave tourism resources. Results indicated that karst cave tourism resources in Zhejiang Province have a significant regional influence, and that resource quality and exploitation are diverse in different regions. Among the regions, Jinhua had the highest exploitation proportion of over 60% and the lowest NNI value of 0.098. Furthermore, regional analysis inferred that different karst caves demonstrate diversity in accessibility to tourism markets, among which the Lingshan Cave, Fengshui Cave, and Xianqiao Cave reveal the highest accessibility index of 2.41. Finally, we put forward a karst cave tourism system in Zhejiang Province based on the Growth Pole Theory and set up an overall scheme for karst cave tourism development. From a regional perspective analysis, the study refined the methods for regional resource re- search and provided a strategic proposal for karst cave tourism in Zheiiang Province.

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.

Minimum safe thickness of rock plug in karst tunnel according to upper bound theorem

High pressure and water-bearing caverns ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technical problem to be solved for karst tunnel construction. Based on the Hoek-Brown nonlinear failure criterion, the minimum safe thickness of rock plug was investigated in the light of the limit analysis theory. On the basis of the proposed failure mode, the expression of the minimum thickness for rock plug was obtained by means of upper bound theorem in combination with variational principle. The calculation results show the influence of each parameter on safe thickness and reveal the damage range of rock plug. The proposed method is verified by comparing the results with those of the drain cavern of Maluqing Tunnel. The research shows that with the increase of compressive strength and tensile strength as well as constant A of Hoek-Brown criterion, the safe thickness decreases, whereas with the increase of cavern pressure, tunnel diameter, and constant B from Hoek-Brown criterion, the safe thickness increases. Besides, the tensile strength, or constants A and B affect the shear failure angle of rock plug structure, but other parameters do not. In conclusion, the proposed method can predict the minimum safe thickness of rock plug, and is useful for water burst study and prevention measures of tunnels constructed in high-risk karst regions.

DEVELOPMENT AND DESIGN OF A DISASTER INFORMATION SYSTEM ON REGIONAL KARST ROCKY DESERTIFICATION

Based on a systematic analysis about the design principles, systematic objectives, clients’ demands and functional modules of the regional karst desertification disaster information system, a systematic application plan was proposed in this paper that the mainstream technologies like COMGIS, etc. can be used for secondary development, and Du’an Yao Autonomous County of Guangxi was taken as an example to illustrate the application of geographical information system in development of karst desertification disaster information system, and to provide a feasible plan for realization of accessory decision information aiming for sustainable development of karst desertification area.

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