EP-4222508-B1 - METHOD OF DETERMINING BORING POINTS USING GEOSTATISTICAL INTERPOLATION METHOD

Inventors

• YILMAZ, Ferdane

Dates

Publication Date

20260506

Application Date

20210312

Claims (2)

1. A computer implemented method of determining the boring points using the geostatistical interpolation method, characterized in that it comprises the process steps of: • comparing a soil type at an observation point (b) which is a part of a digitally generated ground model layer and a soil type at all measurement points of boreholes (a) which are at a same level with the observation point (b) of the digitally generated ground model (1); • in case of presence of the same soil type (1.1), applying a horizontal variogram (1.1.1); • in case of presence of different soil types (1.2), firstly applying vertical variogram (1.2.1) and then applying horizontal variogram (1.2.2); • computing all necessary regionalized variables (z(x i )) for a kriging equation in order to create a data set (2); • creating correlation matrices for a kriging interpolation (3) by computing a Matrix A correlation matrix (3.1), inverse of the Matrix A (3.2) and vector d correlation matrix (3.3); • determining of weighting factors of regionalized variables (4) • in order to check plausibility (5), check whether result of sum of the weighting factors is 1 (one) (5.1); • if the result of sum of the weighting factors is not 1 (one) (5.1.A), checking the correlation matrices; • if the result of sum of the weighting factors is 1 (one) (5.1.B), applying the kriging interpolation (6); • in order to acquire an estimation error data that may occur in the interpolation (6.1), computing a kriging variance (6.1.A); • determining an uncertainty probability at the observation point (b) (7); • determining uncertainties for all observation points (b) of the digitally generated ground model (8).
2. A computer implemented method according to claim 1 characterized by a step of, in case of the presence of different soil types (1.2), using the resulting value of the vertical variogram as a sill value for the following application of the horizontal variogram.

Description

TECHNICAL FIELD The invention relates to the method of determining the boring points using the geostatistical interpolation method developed to determine the accuracy of the model created with digital systems (software platforms, etc.) on land, sea, space, and air (in the field of meteorology), particularly for tunnel and submarine projects. STATE OF THE ART Soil properties have crucial importance in infrastructure projects. Ground models created using software platforms allow the visualization of underground properties based on geotechnical data in a digital environment. Such models constitute an important analysis factor in decision stages such as the examination of soil conditions, creation of efficient solutions, and determination of routes. Thanks to these models, engineers control all stages of the designed project digitally and decide on which regions additional boring activities will be implemented. However, it is not possible with the current technologies to model soil conditions in an accurate manner. In the state of the art, different data are detected by means of sampling from various depths with boring activities on certain regions for the analysis of the condition of the underground layers. Digital ground models are created with such data. Digitally created models visualize soil conditions by means of using data acquired from geotechnical site investigations. This visualization is conducted with the use of existing platforms. Platform algorithms create layers between boreholes with the use of the information acquired from the ground investigation to identify areas of non-bored soil. The course of the created layers is constituted with the extrapolation method by the algorithms of the modeling systems. Said extrapolation may lead to uncertain areas that are not recognized and determined in the digital ground model. Such uncertainty indicates unknown geological conditions and the unknown areas of the ground. Due to the natural variability of the soil structure and the inhomogeneity of the underground, the exact nature of the soil is unpredictable and uncertain. Due to the statistical deviation and spatial variability in digital models, the uncertainty ratio of the created model further increases. These uncertainties are termed epistemological uncertainties. In the state of the art, a quantitative determination of the uncertain areas of the digital ground model is unavailable and the modeling platforms present no indication of how accurate the created digital model is. The program algorithms make use of simple mathematical functions or deterministic interpolation methods to create soil layers. As said methods create a model without examining the spatial correlations of the data, these are insufficient to indicate the uncertainties. Software platforms only conduct the modeling and do not indicate the accuracy ratios, i.e., epistemic uncertainties, of the modeling. Hence, the planning based on the created digital model may be inaccurate. Such uncertainties regarding the ground properties pose a risk for engineers during the analysis. This may lead to high additional costs, damages, and even endangerment of human life. Therefore, the decision process and the planning are affected. The identification of the risky areas in the digital ground model becomes an important problem to be solved due to the increasing use of software platforms and the formation of the decision stages based on the created ground model. Therefore, this invention has been developed using statistical methods to determine the accuracy of the digitally created ground model. DESCRIPTION OF THE INVENTION In the related art, a study, Kim, M., Kim, HS. & Chung, CK. A Three-Dimensional Geotechnical Spatial Modeling Method for Borehole Dataset Using Optimization of Geostatistical Approaches. KSCE J Civ Eng 24, 778-793 (2020). https://doi.org/10.1007/s12205-020-1379-1 discloses a geotechnical three-dimensional spatial modeling was implemented using an optimized geostatistical interpolation approach at a bridge construction site in the south-central part of the Korean peninsula. The geotechnical investigation data were collected and standardized for the construction of a geo-database. For the site-specific stratification, a kriging-based integration of the geo-layers and the seismic velocity from a seismic refraction survey were applied. The value from a standard penetration test (SPT)-N of an uninvestigated location was predicted using parametric and nonparametric geostatistical methods. Three-dimensional spatial interpolations are accomplished using ordinary kriging, a sequential Gaussian simulation with a normal score transformed dataset, and a sequential indicator simulation using the geodatabase. A leave-one-out cross validation was carried out to quantitatively evaluate the reliability of the three-dimensional modeling. Finally, a three- dimensional geotechnical spatial model assigned with subsurface stratification and SPT-N values w