1. What is engineering geological survey?
Geological survey is the work of researching and evaluating the geological conditions of a project at the construction site to determine the ground structure, physical and mechanical properties of the ground layers, underground water conditions and geological hazards serve the planning, design and foundation treatment work.
2. Why is geological survey necessary?
Construction geological surveys provide information to:
‒ Assess the suitability of the location and environment for the proposed construction projects.
‒ Design and select foundation solutions for the proposed project in a reasonable and economical manner.
‒ Propose the most effective construction methods, foresee and predict difficulties and obstacles that may arise during construction.
‒ Identify changes in the geological environment due to economic activities - human construction, as well as the effects of those changes on the project itself and neighboring structures.
‒ Evaluate the safety level of existing works, design renovation and upgrade existing works and study cases that have occurred causing damage to the works.
3. Steps to perform geological survey
The main types of work in engineering geological surveys include: drilling, excavation, static penetration, dynamic penetration, geophysics, static compression, horizontal compression, wing cutting... Such activities are carried out according to regulations. methodical geological survey.
Step 1: The designer or project owner provides information about the campus area, scale, structure, construction load, and expected foundation solution to the construction geological survey department. The survey department coordinates with the designer or project owner to determine the volume, location and depth of exploration.
Step 2: Geological survey staff conduct exploratory drilling using a specialized drilling machine, which can be XY-1 or HT-150E. The geological exploration drilling process also combines taking soil samples to the laboratory and standard penetration testing (SPT) at the site. For every 2 meters of drilling, 1 soil sample will be taken for physical and mechanical testing, then field SPT will be performed.
Step 3: Conduct sample analysis in the laboratory. The laboratory sample is tested for 9 physical and mechanical criteria of the soil sample.
In addition, large-scale projects must also combine a number of other experiments such as:
+ consolidation compression test,
+ Uniaxial compression test with side expansion,
+ UU unconsolidated undrained triaxial compression test,
+ CU undrained consolidation triaxial compression test,
+ Testing water samples for concrete corrosion,...
Step 4: Prepare a geotechnical survey report, propose a number of related issues. The geotechnical survey report is prepared according to TCVN 9363: 2012. Provides necessary data for designers to calculate and select foundation solutions suitable to the project's geological conditions to ensure construction stability. program and achieve economic efficiency.
