Value of engineering geology in water conservancy and hydropower engineering
First, the methods and characteristics of geological survey of water conservancy and hydropower engineering
1. 1 engineering geological mapping
Engineering geological surveying and mapping is a basic work in engineering geological survey of water conservancy and hydropower. Before engineering design, geologists should find out the spatial distribution law of engineering geological conditions in the proposed building area in detail, and truthfully reflect it on the topographic map according to a certain proportion, as the basis for engineering geological prediction, and provide it to the design department for use.
1.2 engineering geological exploration
The study of any engineering geological conditions and engineering geological problems of water conservancy and hydropower, from surface to underground, from qualitative to quantitative evaluation, is inseparable from exploration, which includes geophysical prospecting, drilling and pit exploration.
1.3 field test of engineering geology field test is an important survey method often used in engineering geological survey of water conservancy and hydropower, and it is the main means to obtain the parameters needed for quantitative evaluation of engineering geological problems and engineering design and construction. Field tests of water conservancy and hydropower projects include drilling water pressure test, grouting test, load test and permeability test. The development of field test level of water conservancy and hydropower engineering geology is mainly reflected in the development of test instruments and equipment.
Application of 1.43S technology
3S technology refers to the integration and floorboard of global positioning system (GPS), remote sensing (rs) and geographic information system (GIS). Remote sensing technology is the basis of 3S technology and provides the main remote sensing information source. GPS technology is used for the accurate positioning of remote sensing information, while GIS technology provides auxiliary information and expert thinking for the acquisition of remote sensing information, manages and analyzes the extracted information and has the function of mapping. In recent years, 3S technology has been applied in some super-large and large-scale water conservancy and hydropower projects in China, and many large-scale water conservancy and hydropower projects have adopted 3S technology and achieved fruitful results.
1.5 Geological characteristics of water conservancy and hydropower engineering
The characteristics of engineering geology of water resources and hydropower are: supernormality and complexity, practicality and experience, long-term and hidden engineering geological problems.
Second, the engineering geological problems and conditions existing in water conservancy and hydropower projects
2. 1 engineering geological problems in the construction of water conservancy and hydropower projects
In the construction of water conservancy and hydropower projects, due to the change of the original geological environment, various engineering geological problems have been formed, such as debris flow, slope sliding, slope collapse, cave surrounding rock collapse, geological defects and so on.
2.2 reservoir engineering geological problems
After the impoundment of the reservoir, the water level rises, the water depth increases, and the flow velocity slows down. The water near the dam is like a still water body, forming a huge artificial lake, which will have an impact on the geological environment and production of the reservoir area and its adjacent areas, causing engineering geological problems such as leakage, immersion, siltation, bank collapse and induced earthquakes.
2.3 Geological conditions of water conservancy and hydropower engineering
The engineering geological problems of water conservancy and hydropower projects are not isolated and accidental, but closely related to the natural conditions and environment in the construction area of water conservancy and hydropower projects. Their formation, development and changes are all the results of the influence of engineering activities on the natural geological conditions here. These geological conditions that directly or indirectly affect the planning, design, construction and normal use of engineering buildings are engineering geological conditions, which mainly refer to topography, stratum lithology, geological structure, hydrogeological characteristics and physical geological phenomena.
Three, the typical engineering geological problems and countermeasures under the conditions of water conservancy and hydropower engineering
3. 1 debris flow
The conditions for the formation of debris flow are as follows: there should be rich solid matter in the basin, which can supply debris flow continuously; There should be steep terrain and gully bed with large longitudinal slope; Provide abundant water resources to the middle and upper reaches of the river basin in the form of heavy rain or melting of heavy snow and ice and bursting of lakes. The principle of debris flow prevention and control is to put prevention first and set up engineering measures. The following preventive measures can be taken: prevention: do a good job in soil and water conservation, regulate surface runoff and strengthen dikes in the upstream catchment; Interception: a series of intercepting structures are set up in the middle reaches circulation area; Drainage: Set drainage facilities downstream of debris flow to smoothly remove debris flow.
3.2 Slope sliding
The condition of slope sliding is that the original slope structure is destroyed and the external load of slope exceeds its bearing capacity. Landslide prevention and control measures: drainage, slope elimination, anti-slide pile, anti-slide retaining wall, prestressed anchor cable anchoring measures, grouting method, sand drain sand pile reinforcement method, baking, etc.
3.3 Slope collapse
Occurrence conditions and development factors of slope collapse: the slope is 55-75 degrees, and the surface is uneven; Rock properties and joint degree: composition of soft and hard rock interlayer; Geological structure: rock occurrence and tectonic action. Treatment measures of slope collapse: blasting or wedging, grouting, adjustment of surface water flow, paving and covering, slope spraying concrete, etc.
3.4 Reservoir earthquake
Reservoir earthquake refers to the earthquake induced after reservoir impoundment. The conditions of reservoir earthquake are: geological conditions and excitation conditions, in which excitation conditions include direct effects and indirect effects. Reservoir-induced earthquakes are mainly of magnitude 3. The largest reservoir-induced earthquake in China is the 6. 1 earthquake induced by the Xinfengjiang Reservoir in Leguang. The magnitude of mine earthquake is 3.4 ~ 3.8, which is generally small and shallow. Preventive measures for reservoir earthquakes: minimize the damage to geological conditions that can induce reservoir earthquakes, adopt effective methods to predict the frequency and level of reservoir earthquakes, and formulate emergency plans to prevent reservoir earthquakes. (This article is from Value Engineering magazine. For a brief introduction of Value Engineering magazine, please refer to. )
Four. conclusion
Water conservancy and hydropower projects are carried out in various geological environments, and there must be some connection and restriction between water conservancy and hydropower projects and geological environments. The restriction of geological environment on hydropower engineering buildings will affect the safety, stability and normal operation of engineering buildings to a certain extent, and will also increase the project cost due to some adverse geological conditions. However, the construction of water conservancy and hydropower projects can affect the geological environment in many ways, leading to changes in different degrees and ranges. Therefore, the construction of water conservancy and hydropower projects must foresee the basic forms and laws of mutual restriction according to the specific geological environment and the way, scale and type of project construction, so as to develop and utilize the geological environment reasonably and effectively and properly protect the geological environment.
Model essay 2 of engineering geology: practical teaching methods of engineering geology
The mountains in the western suburbs of Hangzhou surround the West Lake, with bright water and lush mountains, and a vast plain in the north and east. Hangzhou is rich in landscapes, lakes and mountains, with beautiful mountains, rocks, caves and Shelly, and various landforms. The West Lake syncline structure extends to the northeast, uplifts to the southwest, and gradually lowers the topography of Hangzhou from southwest to northeast. Generally speaking, the area can be divided into two geomorphic units: the western and southwestern parts of the West Lake are hilly areas, and the peripheral northern, eastern and southern parts are plain areas. Hilly areas can be further divided into two small areas: low hills and hills. The plain is divided into the alluvial plain of the West Lake and Tunxi River basins in the north and the alluvial plain of the Qianjiang River basin in the southeast.
Practical teaching of engineering geology
Engineering geology practice is a very important teaching link in the undergraduate teaching of engineering geology, and it is also an essential practice link in the four-year teaching of this major. Based on the theoretical knowledge of soil mechanics, rock mechanics, engineering geological foundation, engineering geological investigation and other courses, according to the technical requirements of engineering geological site selection survey and preliminary survey stage, students can obtain perceptual knowledge of engineering geological practice, consolidate and deepen theory, promote the combination of theory and practice, and lay a preliminary foundation for future engineering geological site selection survey or survey.
1. Practice content and requirements. Visual identification of rocks and soil, observation of stratigraphic section; Basic identification of folds and fault structures; Identification of rock mass structural plane types and structural forms, field identification and identification of different rock mass structural types, and mapping statistics of rock mass structural planes; Identification of soil structure types; Understand groundwater types and hydrogeological conditions; On-site identification, investigation and mapping of various environmental geological and adverse geological phenomena (landslides, caves, collapses, etc.). ), preliminary analysis and evaluation of their causes and their influence on site stability; Mainly to master the working methods of engineering geological surveying and mapping, visit and understand the means of engineering geological exploration such as static sounding, standard penetration, drilling logging and sampling; On the basis of understanding the regional stratum and structure of Hangzhou urban area, focusing on the area near Zhejiang University, through engineering geological mapping and data collection, the engineering geological profile, plan and site selection survey text report are compiled.
2. Practice teaching. Practice is divided into four routes. The first route is the bridge stratum profile route, Pagoda of Six Harmonies? Qiantang River Bridge North Railway Line? Baguatian? Yuhuangshan; Route 2: Qiantang River? Investigation route of adverse geological phenomena in Nanfeng; Route 3 is Zhejiang University? Wu Qingzhi? Feng Ling? Yuhuangshan? Yuquan; Route 4 is Zhejiang University? Huanglongdong? The practice of Bat Cave is to systematically identify the stratigraphic lithology and its boundary marker layers in Hangzhou. Describe lithology, observe and describe the color, composition, structure, structure, fossils and weathering degree of exposed rocks, master observation methods and description points, and collect rock samples; On-site identification methods of rock mass structure types: landslide identification, morphological mapping, etc. ; Cave survey and mapping; Investigation of sinkholes and karst collapse; Statistics of joints and cracks in rock mass; Identify geomorphic units and determine zoning boundaries.
Discussion on practical teaching methods of engineering geology
Engineering geology is a very practical science. Without some practice, many engineering geological phenomena can't achieve good teaching results only through the concepts and theories in books. As the saying goes? Practice makes true knowledge? This fully shows the importance of experimental practice teaching. Through practice, verify, consolidate and learn the theoretical knowledge related to experiments, deepen the understanding of subject knowledge, cultivate students' scientific thinking and rigorous work style in line with dialectical materialism and seek truth from facts, and stimulate and cultivate students' creative ability.
1. Stimulate students' interest in engineering geology. As an internship base, Hangzhou itself is very attractive to students. In practice, students' love for engineering geology is induced. Heuristic teaching has many functions. Through heuristic teaching, students' interest and exploration spirit can be stimulated, students' initiative and enthusiasm can be mobilized, students can effectively master knowledge and skills, and the formation and development of students' intellectual factors, non-intellectual factors and ideological morality can be promoted. Each internship route should be assigned tasks before the internship; Every time you climb a mountain, every student should have the courage to conquer it, climb it, study it and understand engineering geological phenomena. The team that takes the lead in completing the task should be rewarded. The performance enlivened the atmosphere when having a picnic on the mountain. Stimulate students' internship enthusiasm. In practice, teachers should know about local customs, history and geography, and link geological phenomena with humanistic knowledge, customs and habits, and economic development. For example, what role did some special landforms play in ancient military wars? What is the relationship between the class in a region and the famous products in that region? What are the local folk customs of some lakes and mountains formed by geological processes and what role do they play in tourism? All these will enhance students' interest in nature, thus enhancing their interest in engineering geology.
2. Cultivate students' independent observation ability. Scientific research begins with observation, especially engineering geology. Some people turn a blind eye to rich geological phenomena, while others are good at observing and discovering something. The difference between them is that they don't pay enough attention to observation and have different observation abilities. Field practice is the most concrete and effective way to cultivate students' observation ability. Be diligent and observant. Diligent observation means that students can actively and independently observe. In the field practice, teachers usually preview the phenomena that students want to observe, knowing fairly well. The practical and effective method is to let the students observe and discover by themselves, and the teacher can observe the content by prompting and dialing. Good observation refers to comparing different phenomena and finding out their essential reasons. In practice, teachers can demonstrate to students, grasp two or three phenomena and analyze them deeply, so that students can draw inferences from others and master ideas and methods. In this process, teachers should pay special attention to encouraging students to put forward their own opinions and explanations, even if they are wrong.
3. Cultivate students' team spirit. Any project is a systematic project, which requires unity and cooperation and a clear division of labor. Many times, it is difficult to handle all kinds of complex problems completely and take effective actions by individual ability alone, so it is also very important to cultivate teamwork spirit. Students' team spirit can be cultivated through the measured stratum profile and independent drawing stage. Before work, they should divide their work according to the tasks of drawing, recording, fixing points, measuring occurrence and collecting samples, and the final results should be sorted out and analyzed through discussion. All members of each group should express their opinions and brainstorm, and finally complete the mapping to avoid fighting each other.
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