Site Investigation and Soil Boring Services in San Antonio, TX
What Is a Geotechnical Site Investigation?
A geotechnical site investigation is a structured program of subsurface exploration. It involves drilling into the ground, collecting soil samples at different depths, running in-field tests, and analyzing those samples in a laboratory to determine what the soil is doing below the surface.
The data goes into a geotechnical report. Structural engineers, civil engineers, and architects use that report to design foundations, retaining walls, pavements, and other elements that depend on knowing what is in the ground.
Our geotechnical engineering services in San Antonio cover site investigation and soil boring for projects ranging from single-family residential lots to large commercial and infrastructure sites. San Antonio subsurface conditions vary dramatically across short distances. The transition from Blackland Prairie clay to Edwards Plateau limestone can shift within the same neighborhood. That variability makes thorough site investigation especially important here.
- Hollow-Stem Auger Drilling
- Split-Spoon Soil Sampling
- Standard Penetration Testing (SPT)
- Groundwater Depth Observation
- Moisture Content & Atterberg Limits
- Grain Size Analysis
- Subsurface Profile Interpretation
- PE-Sealed Engineering Report
Why Work With San Antonio GeoTech for Site Investigation
Experienced Drilling and Field Crews
Our crews use hollow-stem auger equipment to advance boreholes through clay and transition to core drilling when we hit limestone. Field work is documented carefully according to standard field procedures. Field work is documented carefully so the report reflects exactly what was found below the surface.
Reports That Give Your Engineer What They Need
A site investigation is only useful if the report communicates the findings clearly. Our reports include detailed boring logs, lab test summaries, and specific recommendations your design team can put to use right away.
Turnaround That Keeps Your Project Moving
We complete field work and lab testing efficiently. Most reports are delivered within 7 to 10 business days after our field work wraps up.
When Do You Need a Site Investigation?
Before Designing Any New Structure
A new building, retaining wall, infrastructure element, or significant site improvement needs subsurface data before the design team can make reliable decisions. Starting design without that data means working from assumptions that may not hold.
When the Site Has Unknown or Unusual Conditions
Sites with visible fill, signs of previous construction, drainage issues, or unusual topography deserve a closer look below the surface. Old buried structures, soft zones, or variable fill can create serious problems if they go undiscovered before construction starts.
For Permitting and Regulatory Requirements
Many local jurisdictions and state agencies require a geotechnical engineering investigation report as part of the permit application for commercial and large residential projects. Our reports are prepared to support those requirements, though acceptance depends on the jurisdiction and specific project scope.
How Our Site Investigation Process Works
Step 1: Scope Development
We review your project information including the site plan, structure type, anticipated loads, and any existing data. We determine how many borings are needed, at what depths, and what testing will be performed. You know the full plan before our crew mobilizes.
Step 2: Utility Clearance
Before our crew starts drilling, underground utilities are located and marked through the Texas 811 system. This is a required step on every project.
Step 3: Drilling and Sampling
Our crew advances boreholes using hollow-stem auger equipment. Soil samples are collected at regular depth intervals using a split-spoon sampler. Standard Penetration Tests are performed and blow counts are recorded at each interval. In areas of Kendall, Comal, and northern Bexar County, we transition to rock coring when we encounter the Edwards Plateau limestone.
Step 4: Groundwater Observation
Our crew notes groundwater depth in each borehole. This affects foundation design, drainage planning, and any below-grade work.
Step 5: Laboratory Testing
We send samples to the lab for moisture content, Atterberg limits, grain size analysis, and other tests depending on what the field encountered and what the project requires.
Step 6: Engineering Report
Our engineers compile field and laboratory data into a geotechnical report with boring logs, test results, subsurface interpretation, and recommendations specific to your project. Reports are reviewed and sealed by a licensed Texas PE.
Frequently Asked Questions About Soil Borings in San Antonio
How deep do soil borings typically go in San Antonio?
Residential borings typically reach 15 to 25 feet. In Hill Country areas, we may hit limestone refusal at 5 to 10 feet. Commercial projects may require 30 to 50 feet or deeper depending on structure type and load conditions. We recommend appropriate depths based on your specific project.
How many soil borings do I need?
A single-family residential project typically needs two to three borings. A commercial building may need four to eight or more depending on site size and structure type. We develop a recommended program based on your project scope.
How long does a site investigation take?
Our residential field work is usually completed in one day. Larger commercial investigations may take two to three days. Reports are typically delivered within 7 to 10 business days after field work.