Engineering geology. Engineering and geological survey

Geology is the science of the earth. It represents a whole complex of scientific disciplines and industrial branches connected with the study of the earth's crust and its more profound spheres. The tasks of geology are aimed primarily at understanding the patterns of formation and placement of MPI (mineral deposits). Most of the specific issues solved in modern geology, refers to the depths of the order of 10-15 km, due to the geological depth of the cut in the areas of ancient folding and the current level of technical capabilities for mining and exploration of minerals.

General concepts

Engineering geology is a scientific and technical branch of geology, which studies the features and regularities of interaction between the geological environment and engineering structures. The object of engineering geology is the upper layers and horizons of the earth's crust, the geological conditions for their formation and occurrence, morphological, strength and dynamic characteristics in connection with the engineering and economic activity of man.

Along with highly specialized problems, engineering geology provides for the study of geological composition, soil properties and composition, hydrogeological conditions, destructive geological processes, and a number of other issues. Therefore, the foundations of engineering geology include the need for certain broad knowledge in a number of related geological disciplines, including general geology, mineralogy, geomorphology, hydrogeology, petrography, tectonics, geophysics, etc.

Goals and objectives

Engineering geological surveys aim to perform a comprehensive and comprehensive assessment of the geological factors caused by human activities in the construction and economic sphere, in conjunction with natural geological processes.

The main tasks of engineering geology, including the study of geological-tectonic, geomorphological, seismic and technogenic factors, concentrate on the development of an engineering and geological justification, which necessarily precedes the construction of facilities with the status of engineering structures. These are civil and industrial buildings and structures, roads and railways, dams, bridges, airfields, subways, underground workings, underground communications and many other objects.

Thus, engineering geology is designed to provide designers, builders and maintenance services of economic facilities with all the data necessary for design and construction, as well as to carry out activities related to their operation.

Based on the results of engineering and geological work, a conclusion is made on the principal possibility of constructing structures and buildings or determine the most favorable areas for their placement. The conclusion should contain recommendations on the preferred method of production, proposals for structures in terms of their maximum reliability and preventive measures to combat possible negative geological processes that could threaten the safety of the building or structure.

The main sections of engineering geology

Being a part of geology as a science, engineering geology, in turn, includes a number of independent disciplines, of which the main are engineering geodynamics, soil science and regional engineering geology.

Groundwater, as the name suggests, is the scientific branch of engineering geology, which is responsible for the structure, composition and properties of soils, the laws of their formation and accumulation, and also the features of spatial-temporal variability due to engineering, construction and economic activities of people.

The object of engineering geodynamics is a wide range of today's geological processes that have a significant impact on the conditions of construction and operation of economic facilities of any scale. Such processes include earthquakes, landslides of various origins, dips, subsidence, cracks, etc. Along with research and forecast, they all call for the development of protective and protective measures, which also applies to the problems of engineering geodynamics.

Regional engineering geology, like other Engineering and geological surveys, studies the features and patterns of the development of the uppermost layers of the earth's crust that form the so-called lithosphere, in connection with the current and planned engineering and human engineering and construction activities. But the subject of regional engineering geology is, by definition, geological factors of a regional scale.

Physical and mechanical properties of rocks and soils

For the performance of design and construction works, the study of physical and mechanical parameters of rocks and soils is of paramount importance, since a number of fundamental decisions related to the choice of the structure design, its size, type, and also the determination of the volumes depend on the calculated strength, reliability and durability of the base of the construction object Construction and related works. In this regard, the physical and mechanical properties of rocks and soils are compulsorily analyzed at all stages of engineering and geological surveys.

The physicomechanical parameters of rocks and soils include the following parameters: granulometric composition, plasticity, particle density, moisture, density, shear resistance, uniaxial compression strength, angle of repose, petrographic composition, subsidence, swelling and shrinkage, modulus of elasticity, coefficient Ground rejection, deformation modulus, suffusion leaching, Poisson's ratio, salt content, filtration coefficient, water absorption, water saturation and a number of additional parameters.

Assessment of engineering and geological properties of rocks and soils is invariably accompanied by an investigation of the material and chemical composition, as well as structural and texture features.

Composition and stages of engineering-geological research

Engineering and geological surveys consistently include reconnaissance work, engineering geological survey, engineering and geological exploration, detailed work during construction, and final surveys upon completion.

The reconnaissance consists in a comprehensive assessment of geological and geophysical studies to determine the feasibility of further, more detailed work. If the geology of the area is sufficiently well studied where geological engineering surveys are planned, the work can begin immediately with an engineering geological survey.

The survey is carried out to study geomorphological and hydrogeological features, engineering and geological properties of rocks and soils, manifestations of active geological processes and an overall assessment of engineering and geological conditions in the area of the proposed construction work.

Based on the results of exploration work, a design and estimate and working documentation is prepared.

Contents of production engineering-geological studies

Typical complex of engineering and geological surveys, as a rule, includes the following types of work :

• Preliminary cameral processing of collected materials;
• Study of aerial photography materials;
• Route research;
• Geophysical works;
• Mining operations, including drilling wells;
• Testing of rocks and soils in the field;
• Hydrogeological observations;
• Stationary research;
• laboratory works;
• Diagnostics of the condition of buildings and structures under construction;
• Complete cameral processing of collected materials;
• Writing of the final report with presentation of graphic materials, recommendations and conclusion.

The final results of engineering and geological surveys

Summarizing the presented material, it may be expedient to list specific and understandable results of engineering and geological research.

So, for the aggregate of engineering and geological work data, the following parameters are calculated and submitted:

• The stability of the rocks of the foundation of the structure to deformation, which leads to "protrusion" from under the basement;
• Degree and timing of compression of rocks and soils in the basement of buildings and structures;
• Stability of rocks and soils in the slopes of quarries, construction pits, road ditches, embankments, ditches, canals and other artificial depressions;
• Stability of hydraulic structures (for example, dams) to shear deformations under the pressure of water reservoirs;
• Predict the behavior of the coast after the construction of reservoirs;
• Stability of the foundations of buildings and structures during the rise of groundwater;
• Stability of engineering and economic structures erected on permafrost, in seismic hazardous areas, in the areas of development of karst cavities, landslides, landslides and other natural disasters.

Regulations

Engineering and geological production work is carried out in accordance with the technical requirements set out in the list (code) of the rules for the production of surveys to justify the project preparatory measures before the construction starts, as well as for ongoing surveys performed in the process of construction and operation of the facilities up to their elimination.

The noted list of regulatory indications for the production of engineering and geological survey work includes a number of building codes and regulations (SNiP), regulating the performance of work in accordance with the procedure established by state regulatory and legislative acts.