Understanding subsurface conditions is a fundamental step before beginning construction, especially in hilly or coastal regions like Pecatu, Bali. On October 2, 2024, Indo Soil conducted a detailed geotechnical investigation at a project site on Jalan Batu Nunggalan, Desa Pecatu, Kecamatan Kuta Selatan, Kabupaten Badung. The investigation was commissioned to assess the land’s load-bearing characteristics and recommend an appropriate foundation system for the planned building.

This type of preliminary study is critical for ensuring structural integrity and reducing risks during and after construction.

Site Overview

Pecatu is a region characterized by limestone bedrock and varied elevations, making it a technically sensitive zone for construction. The location chosen for this project sits on natural terrain with slight variations in topography and underlying rock formations. Given the proximity to cliffs and coastal influences, a detailed soil strength and stability analysis was essential.

Scope of the Investigation

The team performed a series of in-situ tests across three borehole points (B1, B2, B3), which included:

• Borehole drilling with Standard Penetration Testing (SPT) up to limestone refusal

• Soil layer identification and classification

• Determination of soil bearing capacity at different depths

• Elevation and surface topography assessment

The goal was to identify the depth and quality of the hard strata, groundwater conditions, and the most appropriate type of foundation.

Soil Findings and Hard Layer Depth

All three boreholes encountered limestone (hard soil) relatively close to the surface:

• B1: Limestone at 1.2 meters depth

• B2: Limestone at 0.5 meters depth

• B3: Limestone at just 0.2 meters depth

This indicates a highly favorable subsurface profile for shallow foundation systems. Importantly, no groundwater was detected in any of the boreholes, further supporting safe construction at shallow levels.

Bearing Capacity Analysis

Using SPT data and standard bearing capacity formulas, the allowable bearing capacity was found to be 6.00 kg/cm² at all three locations for foundations with widths up to 1.2 meters. This value indicates excellent soil strength and structural support potential, especially given the presence of hard limestone.

For projects in limestone-dominant areas like Pecatu, these values are considered optimal for typical villa or resort-scale development.

Elevation and Slope Considerations

The site’s elevation showed slight variation across the borehole positions:

• B1: Elevation 0.00 m

• B2: Elevation –1.5 m

• B3: Elevation –3.7 m

This demonstrates a gentle downslope, approximately 3.7 meters of elevation difference between the highest and lowest test points. While not extreme, such a slope must be addressed during architectural planning to ensure proper drainage, avoid erosion, and maintain level footings. If cut and fill operations are planned, adjustments to foundation depths must be made accordingly.

Recommended Foundation System

Given the proximity of the hard soil layer and the high bearing capacity, the report concludes that shallow footings (pondasi telapak) are suitable and cost-effective for this location. Recommended foundation depths are as follows:

• B1: 1.2 meters

• B2: 0.5 meters

• B3: 0.2 meters

However, if land leveling (cut and fill) is conducted prior to construction, these depths should be recalibrated according to the changes in surface elevation.

Conclusion

The Batu Nunggalan site in Pecatu offers excellent soil conditions for construction, with shallow limestone layers and high bearing capacity across the test zones. These factors make it ideal for residential or hospitality developments with moderate structural loads. By conducting this investigation in advance, the project stakeholders can move forward confidently, minimizing risks related to soil instability or structural settlement.

Build Responsibly with Indo Soil

Indo Soil is committed to supporting safe, informed development across Bali, NTB, and NTT. With certified engineers and local field expertise, we provide developers, architects, and project owners with actionable geotechnical data they can trust.

To schedule a soil test or request a sample report, contact us at:
Email: admin@soiltestbali.com
WhatsApp: +62 851 3514 2186
Website: www.soiltestbali.com