Ground Survey includes the locations of the underground layers, their condition, what kind of geological structures they consist of, the depth and thickness of the layers, the density of the rocks, their resistivity to electricity, the seismic velocities of the layers and the accelerations between the environments, the depth of the groundwater and the dynamic parameters of the layers during the earthquake. The analysis performed to determine the postures is called ground study.
The aim of the Ground Survey is to make the necessary analysis of the land / area concerned before the construction. These analyzes are important due to factors such as the rock structure of that region, the stance of these rocks in the face of the earthquake, whether this region is in the fault line or determining the distance to the fault. With the soundings carried out in that region, rock types are determined by taking samples from various depths, the hardness of the soil, the reactions they give when interacting with water, whether the ground water is found or not are also learned. In the light of these data, it is determined whether the area is suitable for construction.
Soil survey has been carried out in order to determine the general morphological characteristics of the study area, topo graphic status, drainage properties against surface and flood waters, slope status of the land and the condition of the soil in this context.
Depending on the characteristics of the construction to be built on the location of a construction site, the underground layers, the status, which types of geological structures, thickness, thickness, depth, density, seismic velocities, groundwater, if there is an earthquake to determine the behavior of the earth and the behavior of the general self. ground survey is named as.
In case of soil survey studies, methods are applied differently according to the type of land and the characteristics of the structure. For example, seismic, electrical, magnetic, electromagnetic, gravity or radioactivity methods are among them.
In soil survey studies, increasing the durability of the structure against the earthquake is one of the target subjects. Liquefaction potential of the soil, soil settling and earthquake intensity increase coefficient are among the physical properties that increase the earthquake intensity. The structural features that have increased the intensity of earthquakes are as follows: geological differences under the foundation, visible and invisible fractures and cracks, loose thick alluvial environments, thin rock layers, landslide condition, underground cavities and mechanical resonance layered structures.
Soil surveys are obliged to minimize the damage that will occur in earthquake zones.
Briefly, soil surveys are conducted to determine the locations of the underground layers, what geological structures they are formed, their condition, the density of the rocks, the seismic velocities of the layers and the reactions of these features during the earthquake. In other words, the ground survey means that necessary analysis of the land is required before construction.
The main information obtained by soil surveys are as follows:
- Seismic shear waves and their period and layers
- The acceleration spectrum coefficients of the ground to determine the coefficient of decrease in the earthquake load
- Ground dominance period to avoid resonance of the building core period
- Earthquake acceleration in the field in a possible earthquake
- Ground safety regression in order to prevent deformation in the field and reduce the horizontal load of the earthquake to low levels
- Determination of groundwater level which increased the severity of the earthquake
- Determination of soil hardness, porosity, water saturation and resistance to dynamic deformation
- Determination of the characteristics of the soil to form a control system
It is decided whether the ground is suitable for the building that is planned to be constructed based on these values regarding the land structure. According to the type of foundation to be used during the construction, the values determined by the soil survey are taken into account in the calculation of the seating rate and bearing capacity for each depth.
Soil surveys, which have a very important place in the construction sector, are carried out by authorized test and inspection institutions, in accordance with the relevant legal regulations and standards published by domestic and foreign organizations. The main standard considered during these tests is:
- TS EN 1997-2 Geotechnical design - Part 2: Soil survey and tests (eurocode 7)
