# Geotechnical Property Modeling and Construction Safety Zoning Based on GIS and BIM Integration
## 2 Research Methods
### Geotechnical Parameters Spatial Interpolation Using GIS  
The collection of the geotechnical information from the borehole dataset is very significant for the geotechnical property modeling and zoning, however, the results of the boreholes are derived at a specific boring point. Boreholes dataset provides one-dimensional information about underground soil thereby causing spatial uncertainties. The metropolitan areas have high variation in geography, geology, and geotechnical information. The geospatial interpolation technique is applied to the dataset in this part to interpolate the data for the uninvestigated location. The objective of spatial interpolation of the geotechnical information is to determine and provide soil information along the whole area rather than at a single point that can be utilized for planning safe construction zones. In the data investigation part, any geotechnical parameter can be surveyed or collected, however, the geotechnical parameter data contain only one-dimensional soil information along with the depth. The available geotechnical parameter is spatially interpolated using GIS to provide information around the whole area in this part. Zoning for safe construction planning based on geotechnical characteristics should be built using the geospatial interpolation method. The geospatial interpolation methods are mainly categorized into two methods, namely, deterministic and geostatistical. The deterministic method such as a triangular irregular network (TIN) and inverse distance \begin{table}
\begin{tabular}{c c} \hline \hline
**Category** & **Parameters** \\ \hline Strength & Compressive strength \\  & Cohesion \\  & Shear strength \\  & Tensile strength \\  & Angle of internal friction \\  & Poisson’s ratio \\  & Elastic modulus \\ \hline Classification & Liquid limit \\  & Plastic limit \\  & Plasticity index \\  & Moisture content \\  & Unit weight \\  & Specific gravity \\ \hline Compaction & California bearing ratio \\  & Maximum dry density \\  & Optimum moisture content \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of laboratory test parameters considered in this study. weighting (IDW) don't consider the effect of spatial variation with distance in predicting values at unknown locations and is based on simple empirical or predefined mathematical equations [59]. On the other hand, the geostatistical method such as the kriging method and its variant is very effective across a wide area for interpolating spatial information. The optimum approach with the highest accuracy should be used for making geotechnical zonation. The probabilistic approaches are ranked to be higher accurate in comparison with the deterministic method for geotechnical property interpolation because of its better uncertainty incorporation [10]. Among the various available geospatial techniques, this approach is employing the kriging method of geostatistical analysis. The kriging technique incorporates the effect of both the distance and direction or degree of variation. \[z^{*}=\sum_{k=1}^{n}z_{i}\lambda_{i} \tag{1}\]  
The fundamental equation for expressing the kriging method of spatial interpolation is given (1). Where \(z^{*}\) is the estimated value at the unsampled location, \(z_{i}\) is the value of know data, \(\lambda_{i}\) is the kriging weight, and n shows the number of geotechnical data samples. ArcGIS is an emerging tool that provides diversified techniques for data interpretation, management, analysis, extrapolation, and interpolation. It provides electronic databases that can store and manage the collected geotechnical parameters. The spatial analysis tool in ArcMap can be utilized to develop geotechnical maps of the study area at different depths. As the location of the geotechnical investigation site having geotechnical information at the study area is arranged in a mesh grid pattern, the kriging technique can be utilized in the geostatistical analyst toolbox for analysis considering point data information to make a surface representation.