Geophysical exploration prospect

Study and find out the geological and geographical environment characteristics of the project construction site and its comprehensive applied science related to the project construction. Engineering investigation is for the planning, design, construction, operation and comprehensive management of urban construction, industrial and civil buildings, railways, roads, offshore ports, power transmission and transformation and pipeline projects, water conservancy and hydraulic structures, mines and underground projects, and provides the basic information needed for feasibility evaluation and construction through the survey, exploration, testing and comprehensive evaluation of topography, geology and hydrology. It is the primary link of capital construction. Doing a good job in engineering investigation, especially in the early stage, can demonstrate the construction site in detail, ensure the reasonable progress of the project, and promote the project to achieve the best economic, social and environmental benefits.

China's engineering survey professional system was gradually formed and developed after the founding of the People's Republic of China, mainly including the following majors.

Engineering geological investigation studies various geotechnical engineering geological problems that have a direct impact on the economic rationality of engineering construction, such as rock-soil slip, active fracture, earthquake liquefaction, ground erosion, karst collapse and various complex foundation soils, as well as environmental geological problems caused by human activities (such as underground goaf collapse, slope excavation and filling instability, land subsidence, etc.). ), put forward the engineering construction scheme and geological technical parameters required for design and construction, and evaluate the relevant technical and economic indicators (see engineering geological survey). As early as 1940s, K Karl Terzaghi, a famous engineering geologist and soil mechanic, proposed the integration of engineering geology and soil mechanics. Since 1970s, due to the higher requirements for the coordination of exploration, design and construction in engineering construction, a geotechnical engineering science and technology system based on engineering geology, soil mechanics and rock mechanics has been formed internationally, which has significantly improved the depth and breadth of traditional engineering geology technology. Some domestic exploration units have begun to implement this technical system. Engineering geology itself has developed some new disciplines with different research objects, such as earthquake engineering geology, marine engineering geology and environmental engineering geology.

Engineering survey studies the topographic features of engineering construction sites and the monitoring technology for construction and safe use, and provides necessary basic maps, surveying data and surveying support for all stages of planning, design, construction and operation management. Engineering survey includes urban construction survey (see urban topographic survey and municipal engineering survey), construction survey, railway and road survey, tunnel and underground engineering survey, precision engineering survey, etc. Although the technical content and emphasis are different, many of its basic principles and methods are the same. At present, engineering control survey in various countries is developing in the direction of optimization design, optical, mechanical and electrical integration and data processing, and photogrammetry is developing in the direction of digitalization and automation. Non-terrain photography has been developed and applied in the fields of surveying and mapping of ancient cultural relics, model test, deformation observation and microscopic measurement. , expanding the application scope of engineering survey technology.

Groundwater hydrogeological investigation is an important part of water resources and one of the indispensable natural resources for economic construction. For example, fresh groundwater is an important water supply source for production and life. Underground brine (salt) water is an important chemical raw material; Groundwater with high temperature and special chemical composition is a kind of resource for tourism and medical application (see groundwater resource evaluation). When the groundwater level is too shallow or the salt content is too high, it is easy to cause some environmental hazards, such as swamping, salinization and bank slope instability. In some large-scale construction projects and urban construction, we often encounter some engineering problems related to groundwater, such as preventing reservoir leakage, maintaining slope stability, preventing groundwater pollution, and preventing ground subsidence and ground collapse caused by unreasonable exploitation of groundwater (see rational exploitation of groundwater and artificial recharge of groundwater). Therefore, the improvement and development of hydrogeological theory research and hydrogeological investigation have become an important part of engineering construction.

Hydrogeological exploration in China mostly adopts the method of "combination of exploration and production", from hydrogeological exploration and testing to well drilling, which is connected into a complete set of procedures (see hydrogeological drilling). Therefore, drilling engineering plays an important role in hydrogeology. The development of modern drilling technology is not only reflected in the important innovation of drilling engineering machinery, but also in the introduction of new technologies such as oil drilling and completion.

Engineering hydrology studies the change and distribution of hydrological elements in rivers or other water bodies, predicts future runoff, and provides hydrological basis for engineering planning, design and construction management. Engineering hydrology is particularly important for the construction of water conservancy, railways, highways, tunnels, bridges, drainage and other projects, as well as the research on the law of recharge and discharge of groundwater resources and its management, and it is an important part of engineering investigation. With the development of automatic test equipment, remote sensing aerial survey technology and computer technology, engineering hydrology has made great progress from observation technology to theoretical analysis and calculation method, which is of great significance to improve the accuracy of hydrological analysis and calculation, hydrological forecast, hydrological test and hydrological investigation, and ensure the rationality of engineering design and the safety of operation.

Engineering geophysical exploration uses modern geophysical exploration technology to serve engineering geology and hydrogeology exploration, which can speed up the investigation, reduce investment, enrich the physical parameters needed for engineering geology and hydrogeology investigation, and make the investigation effect more perfect. It is an important means of investigation and has a broad prospect. For example, this advanced method can be used to detect the spatial distribution of hidden geological structures, strata and aquifers, and obtain in-situ test data of geotechnical physical, mechanical and dynamic parameters. In recent years, in addition to the commonly used resistivity method, shallow seismic refraction exploration and electrical logging, shallow seismic reflection, shear wave earthquake, engineering seismic survey, acoustic wave, underwater acoustic, radioactivity, electromagnetic wave exploration, comprehensive logging and space remote sensing technologies have also been developed.