Geotechnical information system employs spatial analysis to utilize information gathered from Cone Penetration Testing (CPT)

Surakarta has diverse structures, including malls, shopping centers, hotels, offices, markets, hospitals, colleges, and schools. However, the Regional Government lacks a comprehensive data information system about the Cone Penetration Test (CPT). Such a system benefits investors seeking to develop new infrastructure in Surakarta. In order to tackle this problem, a research study was carried out to develop an Information System based on CPT data regarding the depth of hard soil throughout the city. The investigation analyzed pre-existing CPT data, its compilation, and cartographic representation. However, the arbitrary allocation of CPT data presents a challenge. Results of the study indicate that the most predominant depth of compacted soil qc 250 kg/cm2 in Surakarta is 3-5 meters below the surface. Moreover, comparing the depth of CPT soil in the field with GIS at multiple observation points indicates findings that mostly conform to GIS predictions and those of in situ tests. Combining CPT data with ArcGIS software has been a highly successful approach in identifying projects and providing robust geotechnical information.


Introduction
Surakarta City has experienced a steady increase in its economic growth rate, necessitating the planning and development of its infrastructure [1], [2], including civil buildings, roads, terminals, bridges, and other related facilities.However, a building permit, popularly known as IMB [3], is required before embarking on any infrastructure development project.Several reviews are necessary, including thoroughly investigating the site's geotechnical aspects, such as the soil's physical condition.The integration of building systems [4,5], particularly the Internet of Things [6,7], has been significantly influenced by the emergence of digital technology.
Located along the banks of the Bengawan Solo River, Surakarta City is set in the lowlands, approximately 90 meters above sea level.However, the soft alluvial sedimentary [8] soil prevalent in the river basin area poses a challenge for constructing civil buildings [9].The soil's high compressibility [10], low bearing capacity, and tendency to swell require careful [11], [12], [13] consideration in foundation design [14] , [15].Therefore, obtaining information on soil quality to support the load is crucial.Soil investigations in the laboratory or through in situ testing using the Standard Penetration Test (SPT) or Cone Penetration Test (CPT) can provide the necessary information to ensure a strong foundation [16].Soil investigation is a vital part of civil engineering design and construction [17][18][19][20][21], [22,23].With the growing significance and broad scope of Cone Penetration Testing (CPT), engineers can now access various applications.CPT can measure the thickness and quantity of soil properties, identify geological, hydrological, and environmental phenomena, map horizontal stratigraphic elevations, and even describe sediment deposits from pre-historic earthquake records.This valuable data can significantly reduce the time and cost of a project during the feasibility study phase.Geotechnical engineers rely on soil formation and physical properties to make informed decisions and designs, and information technology applications, such as Geographic Information Systems and database systems, are essential for effectively managing and interpreting data in the geotechnical field [24][25][26][27][28][29][30].
To enhance the feasibility, safety, and sustainability of infrastructure development in Surakarta, the regional government must acquire complete data on CPT.CPT is used for an initial review of new infrastructure development by investors who build buildings in the area.The Soil Mechanics Laboratory at Universitas Sebelas Maret Surakarta frequently conducts the CPT test.However, many test data are stored in the laboratory file cabinet and never analyzed or compiled for the entire Surakarta area.An information system based on CPT data should be established to provide crucial information on the depth of hard soil throughout the region.This system will enable investors and civil engineers to make informed decisions and designs, enhancing the feasibility, safety, and sustainability of infrastructure development in Surakarta.

Methods
The research study is being conducted in the city of Surakarta, which is located in the Central Java province of Indonesia (as shown in Figure 1).The study aims to determine the area's average depth of hard soil layers by analyzing Cone Penetration Tests (CPT) data obtained from the UNS Soil Mechanics Laboratory, supplemented by maps.

Figure 1. Location of the study area
The primary data for the research is obtained from the CPTs conducted at the UNS Soil Mechanics Laboratory.The location coordinates of the research site are determined using GPS and Google Earth tools, while the ground level elevation is determined using maps.The CPT data is then analyzed to identify the average depth of hard soil layers and the location coordinates of the research site.They were consulting a graph or table that identifies the depth of hard soil at the point of interest.
The average depth of hard soil is calculated based on the qc value of 250 kg/cm2 from multiple test points at a single project location, using the most profound qc value.Ensures that the data obtained is accurate and reliable.The CPT location is accurately determined using GPS surveying.At the same time, the ground level elevation is plotted on a map by interpolating the contours of Surakarta City with the help of ArcGIS facilities such as 2D and 3D analysts (Topo to Raster).
Finally, the mapping results obtained through GIS and field CPT are compared with new CPT data available at the Soil Mechanics Laboratory.This comparison ensures that the data obtained is consistent and reliable, allowing for better decision-making processes.Overall, this research study aims to enhance soil quality by breaking up hard soil layers, and the detailed analysis of CPT data is crucial in achieving this goal.

Results and Discussion
A comprehensive and detailed distribution map of soil depth in Surakarta has been meticulously produced.The map uses a graduated color system to represent each location, clearly showing the soil depth across the municipality.The data set consists of 132 points, carefully charting the depth of the soil from the surface.The map shows that most locations have a soil depth classification ranging from 3 to 5 meters from the surface.Notably, the central area of Kecamatan Jebres has the most scattered locations.Interestingly, Kelurahan Penumping stands out with the highest hard soil depth value, averaging 19.8 meters below ground level.In addition, Kelurahan Punggawan and Kelurahan Timuran are also noteworthy, with hard soil depths of 19.2 meters from the surface.
It is essential to consider the surface contour when analyzing an area, as evidenced by the crosssection diagram of the Surakarta city area in Figure 3.This diagram depicts six contour line elevations, each represented by a different color: dark green (125 m), light green (112.5 m), orange (106.5 m), red (100 m), yellow (93.75 m), and orange (87.5 m). Figure 4 showcases the DEM findings for 10X10, with the shadow contour derived using ArcGIS features such as 2D and 3D analysts.It was accomplished by inputting the contour elevation parameters and high points.The CPT outcomes were then obtained by subtracting the surface elevation from the complex soil elevation data.Finally, Figure 5 is presented using a 3D analyst (Kriging), showcasing a more detailed area analysis.
Creating the map of complex soil depth distribution has been an essential step toward understanding the soil characteristics of the Surakarta municipality.Using a graduated color scheme has made it easier to identify the variations in the soil depth values across different locations.The mapping results revealed that the central part of the city, specifically Kecamatan Jebres, has the highest concentration of soil depth values in hard soil.This information is critical for planners and policymakers as it can help them make informed decisions about urban development in Surakarta.
The surface contour is another crucial variable illustrated in the cross-section.The contour lines are depicted using different colors, each representing a different height.This information is vital for understanding the topography of the city, which can impact various urban planning decisions.The DEM results have been obtained using ArcGIS facilities, such as 2D and 3D analysts, which have helped interpolate the contour elevation parameters and high points.The CPT results, which have been derived by subtracting the surface elevation from the complex soil elevation data, have provided valuable insights into the soil characteristics of the Surakarta municipality.
ArcGIS facilities, such as 2D and 3D analysts, have been instrumental in creating the maps and obtaining the DEM results.These tools have made it easier to interpolate the contour elevation parameters and high points, which has resulted in more accurate mapping results.Using a 3D analyst, specifically Kriging, has also helped create a more detailed and accurate map of Surakarta's complex soil depth distribution.
The maps and cross-sections created using ArcGIS facilities have provided valuable insights into the soil characteristics and topography of the Surakarta municipality.These insights can help planners and policymakers make informed decisions about urban development in the city.Creating the complex soil depth distribution map has been particularly useful in identifying the areas with the highest concentration of complex soil depth values, which can impact various urban planning decisions.Similarly, the surface contour map has provided valuable insights into the topography of the city, which can also impact urban planning decisions.
Overall, the use of GIS tools, specifically ArcGIS facilities, has been instrumental in creating the maps and cross-sections of the Surakarta municipality.These tools have made interpolating the data easier and created more accurate and detailed maps.The mapping results have provided valuable insights into the soil characteristics and topography of the city, which can help planners and policymakers make informed decisions about urban development.To fully comprehend the soil and topography of Surakarta municipality, it is crucial to create a complex soil depth distribution map and a surface contour map.These two steps are essential in achieving our goal.In order to evaluate the mapping results obtained through GIS and field CPT, a comparison was conducted with the new CPT data available at the Soil Mechanics Laboratory, which can be observed in Figure 6-11.The objective of the comparison above was to evaluate the precision and dependability of various mapping techniques and to ascertain whether the recently acquired CPT data could yield more accurate outcomes.
In order to thoroughly evaluate the efficacy of mapping methods, we conducted a comprehensive analysis of their application across a range of construction projects.Specifically, we examined the DED Youth Center at Manahan Stadium in Solo, the Tennis Sports Center in Pucangsawit, and the Tingal House on Jl Kantil No 19 A Badran.Additionally, we assessed the Audio Technica Development in Penumping, the Annisa Building at the PKU Muhammadiyah Hospital, and the UNS Student Dormitory in Jebres.We chose these particular projects due to their diverse and varying requirements and the differing geological conditions of their respective sites.Through this thorough evaluation, we comprehensively understood the mapping methods' effectiveness across these varied construction projects.
The comparison diagram of field CPT with GIS at each CPT location is depicted in the image above, which visually represents the differences and similarities between the mapping methods.The comparative analysis plays a pivotal role in determining the most appropriate approach for each project, as it facilitates the identification of the strengths and weaknesses of the different techniques.Furthermore, it can guide future decisions concerning the selection of mapping methods for similar projects and contribute to the refinement of more accurate and efficient mapping techniques.
In general, the contrast of map findings with GIS and field CPT and the assessment of new CPT details are vital in ensuring the precision and credibility of mapping techniques in building operations.By implementing such comparisons and assessments, professionals in the construction field can arrive at informed decisions concerning the selection of mapping techniques.They can thereby guarantee the safety and success of their projects.In conclusion, utilizing state-of-the-art cartography technologies and methodologies, like geographic information systems and cone penetration testing, can considerably improve the efficiency and accuracy of construction projects while aiding in the sustainable advancement of the built environment.

Figure 6 .
Figure 6.Comparison of the depth of hard soil from field surveys (CPT) with GIS on the DED Youth Center Surakarta

Figure 7 . 8 Figure 8 .Figure 9 . 9 Figure 10 .Figure 11 .
Figure 7 .Comparison of the depth of hard soil from field surveys (CPT) with GIS on the Construction of the Tennis Sport Centre