Amid global rural decline, the main approach to rural revitalization (RR) is to transform rural ecological resources into development advantages by means of ecological product value realization (EPVR). The fragility of the karst ecological environment limits the development of the karst countryside, and agroforestry is an important way to achieve the ecological protection and economic development of the karst countryside. At present, research on EPVR and RR is rapidly developing. Although there is an increasing number of publications on EPVR and RR separately, the literature on their comprehensive analysis is lacking, and how the karst agroforestry ecosystem can be improved is unclear. The objective of this is to provide an overview of the current research status and challenges of EPVR and RR in order to optimize agroforestry ecosystems in karst desertification control (KDC). This paper systematically analyzed 263 relevant articles on EPVR and RR, and the results are as follows: (1) The number of studies increased exponentially after 2017. The research has primarily focused on the relationship between EPVR and RR, as well as the EPVR and the formation mechanisms of the eco-industry and value accounting of eco-products, which account for 95.53% of the total literature. China has published the most research in this area. At the intercontinental scale, this research is mainly concentrated in East Asia, Europe, and North America. (2) The main progress and landmark achievements in the research on EPVR and RR are summarized. Four key scientific questions that need to be addressed in the future are presented. (3) The above information highlights the three key areas for improving the agroforestry ecosystem in karst desertification control (KDC): the value accounting of eco-products, EPVR, and RR. This study found that EPVR and RR can improve the karst agroforestry ecosystem and further promote rural development, providing significant insights for the overall revitalization of rural areas worldwide and the scientific control of karst desertification.

Soil thickness is closely related to the development degree of rocky desertification, and soil is the basis of ecological restoration and agricultural production in karst rocky desertification areas. In order to examine the spatial distribution law of soil thickness in typical plateau rocky desertification areas, by combining field investigation of soil thickness with geostatistic methods, this paper analyzes the spatial distribution characteristics of soil thickness and its influencing factors in the karst plateau gorge area of the Zhenfeng-Guanling Huajiang small watershed in Guizhou. The results show that the average soil thickness in the study area is only 26 cm, and the average thickness of soil is: Slope farmland > wasteland > forest land. The spatial variability of soil thickness in the study area is mainly intensity. The spatial distribution continuity of soil thickness in wasteland is better than that of forest land and slope farmland. The spatial distribution of soil thickness in forest land has obvious mutation. The soil thickness in slope farmland is characterized by point distribution, and the soil thickness near crops is large. There are significant negative correlations between soil thickness and altitude, bedrock exposure rate and slope. Serious soil erosion under natural and man-made effect is the main reason for the uneven distribution of soil thickness in the study area, and the combination of engineering measures and biological measures can be used to control rocky desertification in the study area. The results are of guiding significance for the control of rocky desertification in the study area and control of soil erosion, ecological restoration and rational agricultural production in other similar areas.

The geoecological environments as the four dimensions for human living and developing consist of compound influences from geosphere, hydrosphere, atmorsphere and biosphere as well as the impacts from artificial actions. Based on the geoecological environmental conditions together with the different characters which are resulted by endogenetic and exogenetic processes, the geoecological environmental types in China will be separated into 12 types and 34 sub-types; meanwhile, on the basis of resource conditions and harmful factors as well as communication and related economic situations, their qualities will, by comprehensive environmental coefficient (Eq),be evaluated. According to the researches on evolutions of palaeo-geoecological environments since Late Tertiary, their evaluations of several important problems in 21st Century are discussed.

In order to study the influences of bedrock exposure rate and soil thickness on water and soil loss in karst areas, the simulation experiments are carried out to study the hydrological process and its driving water and soil movement process by the self-made test equipment. Considering the phenomenon of soil surface loss/underground leakage under karst hydrogeological structure, the results show that the characteristics of surface and underground soil loss rate are that the runoff rate rises rapidly to the peak value and then gradually decreases. There is a significant positive correlation between the soil underground leakage rate and the soil thickness, and a significant negative correlation between the soil surface loss rate and the bedrock exposure rate. With the increase of the bedrock exposure rate, the fluctuation of soil surface loss rate with time is more obvious. The correlations between the sediment yield and the bedrock exposure rate/soil thickness are fine, and the linear correlation coefficients R2 are all above 0.9. The surface sediment yield decreases with the increase of the bedrock exposure rate and soil thickness, and the underground sediment yield decreases with the increase of the bedrock exposure rate but increases with the increase of the soil thickness.

为揭示地下水位变化对土体变形的影响,本文采用上海第④层淤泥质粘土,通过单向压缩试验研究了不同地下水位变化模式下淤泥质粘土的变形特性,并结合电镜扫描与压汞试验进行了微观结构分析.研究结果表明,上海第④层淤泥质粘土的变形与地下水位变化密切相关,当地下水位变化引起的荷载小于前期固结应力时以弹性变形为主,大于时以粘塑性为主,等于时则以粘弹塑性为主,同时各级荷载作用下试样孔隙比与加卸荷循环次数满足幂指数函数关系.微观结构分析显示,上海第④层淤泥质粘土试验前后均以大孔结构为主,受荷后其高孔隙架空结构逐步向离散型结构演化,颗粒定向分布趋于水平方向.相关结论可为地下水位变化诱发地面沉降的治理与控制提供理论依据与技术指导.

双排钢板桩结构是由两排钢板桩、桩间土和拉杆组成的挡土、止水复合结构,由于其较土石围堤占地面积小、施工速度快,较钢板桩整体性好,抗地震和波浪等动力稳定性好,在水利、水运、海岸工程中广泛应用.但由于钢板桩受地质条件影响较大,其使用效果和投入成本不尽相同.本文重点搜集和调查了国内外海岸带工程中使用双排钢板桩的工程案例,分别针对岩溶发育的岩性地基,高渗透性的砂性地基和深厚淤泥质软土地基对双排钢板桩的性能影响和设计约束进行分析.结合原有地质条件和设计资料,采用有限元软件补充计算分析,分析研究在各种不同类型的工程地质条件和水文条件下双排钢板桩的应用效果,总结双排钢板桩在海岸带不同工程地质条件下的适用性.发现在岩溶发育地层施工双排钢板桩需要防止打桩造成垂直度差和岩溶连通性带来的渗漏问题;在砂土地层需要防止钢板桩倾斜变形造成锁扣止水性能劣化,进而导致渗漏水甚至出现流砂;在淤泥地层施工时打入桩施工和桩身止水性能都能得到保证,但可能发生较大桩身整体变形,同时应考虑内侧坑底加固以避免踢脚稳定性破坏.本文的研究对发展海岸带生态工程地质和沿海韧性水工建筑物具有工程指导价值.

By using the samples of fine sand in Shanghai’s seventh layer, creep tests were performed to investigate the deformation characteristics of fine sand under different groundwater table change. It was revealed that the creep of fine sand is closely related to groundwater table change: when the effective force caused by groundwater table change is smaller than pre-consolidation force, the deformation is mainly elastic. When effective force caused by groundwater table change is bigger than pre-consolidation force, the compression deformation is large and the rebound is small; and the deformation is mainly viscoelastic plastic when equal to pre-consolidation stress. Through the scanning electron microscope (SEM) analysis it was found that creep of fine sand is dominated by the slip of particles, not by the breaking of particles. And the fine sand particles are squeezed under the load induced by the groundwater table change, and the particles slide along the indirect contact surface of the particles, resulting in the continuous adjustment of position and relative displacement. Mercury injection test shows that the pore size distribution of fine sand has little change before and after the test.

The basic hydrogeological conditions of karst areas of North and South China are discussed Two major river development schemes and their potential hydrogeologicsl and environmental impacts are considered: the Shanxi-Shaanxi Gorge (Wanjiazhai Water Project) of Yellow River in North China, and the Three Gorges Project of Yangtze River in South China. The water development constructions may have major hydrogeological within the geoecological environmental impacts. The detrimental factors include: karst leakage, earthquake, reservoir margin stability failure, dezertization and pollution etc. The benefits are electrical power generation, flood control and irrigation.

The energy reserves of hot dry rock resources are huge, thus a model to predict engineering production for efficient and stable development and utilization is sought. Based on the geological characteristics of dry rock resources in Guide Basin, Qinghai Province, China, the fully coupled wellbore–reservoir simulator—T2Well—is used to model a production system using water as a heat transfer medium and simulate the system’s operation to analyze the influence of different injection rates on heat extraction. In later production stages, output temperature and reservoir pressure decrease by 10–30°C and 0.5–30 MPa, depending on injection rate; this occurs earlier and to a greater extent at higher injection rates; thermal breakthrough also occurs earlier (7–10 years). The heat extraction rate is 1–20 MW and the cumulative heat extracted is 2.1–24.2 × 10 5 J. Lower injection rates result in relatively low heat extraction rates. For maximum economic benefit, an injection rate of 50–75 kg/s is ideal.

The karst rocky desertification is one of the major bottlenecks for the eco-environmental safety and economical sustainable development in karst areas of China. The formation of rocky desertification is influenced by many factors, and the lithology of carbonate rocks has the most profound influence on it as internal factors. The lithological difference of carbonate rocks determines its weathering process and the way of the accumulation and loss of surface soil, which makes the origin, temporal and spatial evolution rule and governance difficulty of rocky desertification different. In this paper, the limestone and dolomite in the moderate and severe rocky desertification region in the Guizhou plateau are selected as the research objects. Stress-dissolution experiments of carbonate rocks are carried out by the simulating open system of the water environment of epikarst zone. The differences in deformation and dissolution characteristics of limestone and dolomite under different stress conditions are analyzed. In addition, the characteristics of surface and internal pore structure of the rocks are analyzed from the microscopic view. The results further explain why the degree of rocky desertification in the dolomite area is lighter than the limestone area, but it is more difficult to control than the limestone area. These results provide a theoretical reference for the controlling of rocky desertification.

The impact of consolidation pressure, anisotropy and structures are studied on the permeability of silty clay respectively by using the sixth layer soil in Shanghai. Then the microstructure and permeation mechanism are discussed by using scanning electron microscopy. It is revealed that permeability coefficient decreases with the increase of consolidation pressure; and the horizontal permeability is greater than the vertical permeability; the permeability of remolded soil will decrease when compared with the undisturbed soil. Moreover, the microscopic analysis indicates that consolidation pressure makes the soil more compact;there are many granular polymers in the vertical direction while flaky or planar polymers dominate the horizontal direction.The soil is disturbed and the small particles are filled with large pores.The changes of pore types and contact modes between the granular clay particles are the essential reasons for the macro permeability difference of silty clay.

The phenomenon of rocky desertification is obvious in karst plateau of Guizhou, China, and the distribution area of slight–medium–severe rocky desertification is very large in Zhenfeng–Guanling–Huajiang, Guizhou. To explore the cause of formation and development of rocky desertification in the region, the karst development mechanism and characteristics were studied by the method of indoor dissolution test and microscopic analysis. The results show that the dissolution and karst features of carbonate rocks are closely related to geological structure, hydrogeological conditions, and lithology. The dissolution rate is the most affected by the chemical composition and mineral composition, followed by the pore structure and the particle feature. The dissolution rate of carbonate is in positive proportion with the calcite content, while it decreases with increasing content of dolomite. In the same chemical composition, the rock with the finer grains has a faster surface dissolution rate. In addition, the erosion amount will change with the pore aperture and connectivity. Karst morphology is mainly affected by the microstructure and mineral assemblage characteristics of carbonate rocks. In this rocky desertification area, bare rock over a large area will be further eroded, which will form the stone bud, stone forest. At the same time, the hydrodynamic effect of groundwater will erode the rock deeply, and the depression, karst funnel, or deep valley will appear gradually.

In order to analyze the mechanical and corrosion characteristics of carbonate rock and their effects on the evolution of rocky desertification,the study on the corrosion-creep performance of carbonate rock under mechanics-chemistry coupling was carried out.The results showed that 1) Under the condition of mechanics-chemistry coupling,the creep of carbonate rock is obvious.And the initial deformation of dolomite are higher than that of limestone.It shows that under the action of external force,dolomite is more prone to deformation and failure.Besides,the creep deformation of dolomite increases with the loading time.But creep deformation of limestone happens mainly in the early stage of loading,then it tends to be stable.2) Under the coequal concentration of acid solution,the dissolution of carbonate rock is greater than that of unstressed condition in the same period of time.The dissolution rate of dolomite and calcite dolomite is proportional to the stress level.The dissolution rate increases with the increase of creep stress.With the increase of stress,the dissolution rate of limestone decreases at first and then increases.3) The dissolution occurs not only on the surface but also in the pores.The result of corrosion shows the increase of pore diameter and porosity of the rock.4) The mechanical characteristics and chemical properties of carbonate rocks in different lithology cause different forms of weathering and soil erosion,which is an important influence on the formation and evolution of rocky desertification.

The Zhenfeng-Guanling-Huajiang rock desertification demonstration area is a typical karst canyon in Guizhou,where the water and soil losses are serious and many places have suffered from intense rocky desertification.In order to study the intensity and diversity of rocky desertification in the area,11rock and soil samples from the 11 quadrats in the demonstration were collected and their chemical compositions were analysed.The results show that,(1) When the ratio of CaO/MgO in rock is larger and ratio of Rb/Sr is lower,the level of rocky desertification is higher.It means the strength of rocky desertification increases with the ratio of CaO/MgO increasing,and reduces with the ratio of Rb/Sr increases.(2) In the process of carbonate rock dissolution and weathering into the soil,Ca and Mg ions in rocks are taken away.As a result,their contentsin the rock are accordingly reduces,while the content of Mg ion in soil increases in intense rocky desertification areas.(3) The degree of chemical element loss and concentration has slightly differences in different rocky desertification areas.Generally the content instrong and potential rocky desertification area are higher than the mild and moderate rocky desertification area.(4) The ratio of Rb/Sr in the soil is higher,the degree of rocky desertification is more intense,that is the ratio of Rb/Sr increases with the intensity of growing rocky desertification.According to the different chemical elements in different rock desertification areas,this work studies the mechanism of water and soil loss in this area,which provides theoretical and practical basis for research of the water and soil loss and rocky desertification control in the demonstration area.

This paper explores the 12 aspects of geo-environment and construction engineering, including the earth evolution, the structure of geological bodies, the comprehensive utilization of resources, the geo-environmental effect, the engineering construction, the sustainable development and, etc. This paper presents that the good environment could only be created through the conservation and efficient utilization of resources, the joint efforts of disaster prevention and mitigation, as well as the avoidance of adverse environmental effect caused by human activities. This paper concludes that, to build a scientific and ecological earth, the development laws of geo-science must be learnt.

The Guang-Qing freeway reconstruction and extension project is located in Guangdong province, China, extending from Guangzhou city to Qingyuan city. The total project length is 57.6 km, 33 km of which is in a karst area where sinkhole collapses are common. Therefore, there were concerns about the safety and security of the roadbed, bridge piles, and other structures associated with the original roadway. The study addresses karst development, covering layer (overburden), and external factors that contribute to catastrophic sinkhole collapse along the project. The study found that the formation of sinkhole collapses is affected significantly by the degree of karst development and soil characteristics, including thickness. Collapses may be triggered directly by external factors that disturb the natural equilibrium. Such factors include heavy rainfall that impacts soil and groundwater conditions, as well as vibration and groundwater flow disruptions that are caused by pile construction and other engineering activities. Prevention measures were adapted to local conditions and optimized based upon safety, reliability and cost-effectiveness.

With dolomite in Shibing of Guizhou Province as the study object, the authors analyzed its dissolution characteristics and pore characteristics macroscopically and microscopically. Some conclusions have been reached: (1) In many factors that influence the development of Shibing karst, the most fundamental factor is mineral composition, the most critical factor is water, and pore characteristics play a supporting role; (2) The dissolution amount on per unit surface area of superfine grain Shibing dolomite is generally greater than the amount of fine-grained dolomite rock sam-ple. Under the same circumstances of grain dissolution principle, the dissolution amount of dolomite is in positive proportion with CaO and MgO content and the influence of MgO content is larger than that of CaO content. (3) The dissolution rate of Shibing dolomite is not only controlled by particle size of the mineral particles, but also by the internal pore structure characteristics of the rock. The larger the particle size, the higher the porosity, the better the connectivity, the more the beneficial solution seeps into pore, and the greater the amount of dissolution; (4) Dissolution of dolomite is the result of many factors, and all factors must be separated one by one to make a detailed analysis from the macroscopic and microscopic view. On such a basis, more information about the regularity of the karst development can be obtained through a comprehensive study.

The dolomite in the Yuntai Mountain, Shibing, Guizhou, China constitutes the gentle stratum, affected by several weathering processes. It is coupled with a vertical joint development, which makes it easy to form the collapse and stone peaks corroded by running water. The aim of this paper is to study the effects of weathering processes of dolomite outcropping in the Yuntai Mountain (Shibing, Guizhou, China). This work shows the dolomite’s physical and mechanical characteristics, microscopic characteristics of rock and pore structure based on chemical and minero-petrographic analyses. The findings indicate that the dolomite in this region is gray, pure quality and hard-packed superfine grain to fine grain. Mass surface voids suggest that the dolomite’s pass is small and has more pore throat. Its grain cementation is relatively poor. The degree of rock weathering is relatively high. The mechanical strength is lower than that of the surrounding limestone. This work shows how the macro–micro characteristics of the dolomite affect the formation of collapse and stone peaks. This work further focuses on the study of the cone-shaped peak cluster basement and the upper tower-shaped stone peaks, which are the most important features of this region.

The report on the 18th National Congress of Communist Party of China put forward the idea that construction of ecological civilization should be integrated into economic, political, cultural and social construction so as to achieve the aim of “five-in-one”. This development strategy will have an important guidance for the future development of science. For the purpose of building an ecological civilization as the basic starting point and according to the natural conditions of its development effects, this paper summarizes different types of urbanization development and points out the necessity of acting according to circumstances at this stage of the urban population. And then a discussion is made on the geological environment problems in the process of development, with special emphasis placed on the prevalent security issues of water and soil resources, natural disasters of extreme hazards, adverse large-scale integrated environmental effects of the construction and development, and environmental pollution hazards. This paper points out the safety feasibility and importance of the development of new urbanization in accordance with environmental safety and sustainable development. Based on the above analysis and discussion, the authors have divided urban construction into five levels, and discussed the functions of different levels of towns. Importance is attached to the integration and coordinated development of urban and rural areas.

According to analysis of the phenomenon of internal erosion of soils, the phenomenon of internal erosion of soils is that some soil particles departing from soil skeletons become fluidized ones sharing the same velocity with fluid phase. A physical model for the internal erosion of soils is established, and the correspoding constitutive equation is given. The land subsidence caused by the internal erosion of soils owing to pumping confined groundwater is discussed during the construction of third-class deep foundation pits. The numerical model depends on a practical deep foundation pit consisting of 8 layers of soils of Shanghai area. Based on the mathematical-physical model, four governing equations and the finite element numerical method, the calculated results demonstrate that the internal erosion will cause additional land subsidence and deformation.