Geotechnical Investigation
What is Geotechnical Investigation?
A thorough ground investigation is a vital first step in any civil engineering project, providing the critical data needed to design safe, efficient, and cost-effective structures. It helps uncover the site’s geological characteristics, assess soil and rock properties, and identify groundwater conditions. This process ensures potential construction challenges are anticipated and mitigated. From initial desktop studies to on-site inspections and deep borehole drilling, each stage of the investigation contributes to building a strong foundation for successful project execution.
Key Objectives of Ground Investigation
The investigation may also include in-situ tests to assess appropriate soil characteristics, with additional considerations if ground contamination is suspected. The results help select the most suitable foundation type and foresee potential construction challenges.
-
Understanding Soil Strata and Bedrock
Determine the sequence, thickness, and lateral extent of soil strata and the level of bedrock.
-
Sampling and Testing for Engineering Parameters
Obtain representative samples of soils and rocks for identification, classification, and laboratory testing to determine relevant engineering parameters.
-
Identifying Groundwater Conditions
Identify groundwater conditions.
Desktop Study: The First Step
Before field investigations begin, a desktop study is performed. This involves collecting available relevant information about the site to assist in planning the subsequent fieldwork. Resources may include geological maps, aerial photographs, topographical maps, satellite imagery, and historical mapping data.
-
Site Inspection and Preliminary Observations
Before drilling or sampling, an inspection of the site and surrounding areas should be conducted. Observing riverbanks, excavations, and existing structures can reveal valuable information about soil strata and groundwater conditions. Previous experience or data from adjacent owners can further inform the investigation.
-
Fieldwork and Borehole Excavation
The investigation procedure typically involves excavating boreholes or test pits. The number and location should be planned carefully to map the geological structure and detect subsurface irregularities. However, due to soil variability, it is crucial to have a geotechnical engineer perform inspections at critical construction stages to ensure site conditions match the investigation findings.
-
Depth and Extent of Investigation
The investigation depth depends on the project type and size but must cover all strata significantly affected by the structure. For deep foundations, the investigation may extend considerably below the surface. If rock is encountered, it should be penetrated by at least 3 meters in multiple locations to confirm bedrock and rule out large boulders or floaters. In areas with underground cavities or old mine sites, deeper investigations may be necessary.
Drop us an inquiry
Have a question or need more information? Fill out the form below, and our expert team will get back to you as soon as possible to assist with your geotechnical needs.
Looking for Geotechnical Experts?
Whether you’re working on basements, foundations or infrastructure projects, our team delivers solutions to suit your site conditions. With BHM Geotechnical, you can break new ground with confidence.Get in touch with our Sydney, Australia office to start planning your next Project!
Have Questions? Let’s Clear Them Up
-
Geotechnical Site Investigations are conducted to gather information on the physical properties of soil for planned projects and to repair subsurface conditions that have caused damage to earthworks and structures.
-
Geotechnical Investigations are vital in the construction process as it obtains information on the physical properties of soil, rock and groundwater of the proposed site.
-
Typical Geotechnical companies operate by conducting scientific investigations, mainly soil and rock sampling. These samples are analysed and a report is compiled based on the data obtained, the report is then used by structural engineers, architects and construction personnel to appropriately undertake construction in that area with knowledge on the geological formations and ground behaviour.
-
Geotechnical engineers are responsible for investigating the impact that geological formations may have on construction projects.
-
Generally, we aim to get most reports finalized within 2-3 days of completion of fieldwork. However, times can vary depending on the nature and complexity of the report.
-
Geotechnical testing varies in cost depending on the scope of work and complexity of site/developments.
