What is included in a preliminary desktop site review?

Before we go on site we conduct a preliminary review to determine which testing methods and samples we need to conduct. It is one of the most crucial for controlling cost for an efficient field visit. First, we review the site using a variety of mapping tools that allow us to examine its physiological features, including the topography, soil type, ground water and bedrock location. Based on what we find, we choose where and which type of sampling we need to do on-site as well as any other necessary fieldwork.

What is the difference between boreholes and test pit soil sampling?

Both boreholes and test pits are commonly used means of subsurface geotechnical investigation and are used to determine soil density, stability and install ground-water monitoring wells. Boreholes are the most typical sampling and use a steel tube inserted at set depths to take a cross-section of the soil. If continuous depth testing is required, this method can become expensive. For when you need a continuous profile, test pits are preferable and the most economical. As the name implies, a test pit is dug at the site and allows the engineer to see the layers and test for slope stability. However, this method cannot go into bedrock.

When would we recommend shallow vs deep foundations?

Shallow foundations work well in scenarios when there is a stable soil conditions or a good amount of bedrock. We would recommend deep foundations for any structures building on weak, unstable soil conditions.

Why is soil engineering important for civil engineering?

Soil mechanics play a big role in civil engineering because the results of a soil assessment can impact the engineering design process. You wouldn’t want to build a road that lies on unstable soil, or a house on the side of a steep slope prone to landslides.

Geotechnical Services for Civil Engineering

Geotech in Civil Engineering

Preliminary Desktop Site Review

A desktop review is an assessment that does not require an on-site visit to the subject property. These reviews include an initial screening of the property to determine all environmental liabilities or concerns around the area, and a review of existing site information such as published geological maps.

Identifying local environmental impacts and/or laws
Determining basic site conditions

Boreholes and/or Test Pit Investigations

The drilling of boreholes and the excavation of test pits are the most commonly used means of invasive subsurface geotechnical investigation. Both methods provide opportunities to sample, test, and analyze subsurface materials such as soil, rock, and groundwater, and to record a representative log of the subsurface profile.

Facilitates a deep understanding of the surface
Confirms strength and/or presence of bedrock or other obstructions

Shallow and Deep Foundation Design

Foundation design is important because it provides stability during the transfer of building loads from the structure to the soil, especially if the soil is poor quality. Whether shallow or deep foundation design is needed depends on the type of structure as well as the identified subsurface conditions. In general, deep foundations are used for larger buildings such as skyscrapers, and shallow foundations are used for smaller buildings such as homes.

Deep foundations are good for structures that need to be embedded through unstable subsurface layers.
Shallow foundations are good for smaller structures that are constructed in stable ground.

Slope Stability Analysis

Slope stability analysis determines the potential of soil on a slope to withstand movement and subsequent mechanism failure due to sliding or collapsing. This involves both human-made and natural slopes. Slopes can be stabilized by adding extra surface cover or support structures and excavating or regrading slope geometry.

Structures on the side of mountains, hills, etc.
Structures built near earthquake lines

Erosion Risk Assessment and Considerations

Erosion risk assessment, particularly near streambanks, is vital for determining the risk a structure is exposed to during the natural changes of river and stream movement. When water comes into contact with soil, it becomes mobile which poses a risk for any structure.

When your structure is near a body of water
When the area of your site is exposed to high precipitation
Important for planners and policy makers implementing remedial measures and prioritizing areas for construction.

Asphalt and Concrete Pavement Design

Asphalt and concrete pavement design require an understanding of the characteristics and strength of the soil under the road or pathway proposed for construction. Pavements must be able to withstand wheel and traffic loads, environmental stressors, and subgrade materials. Generally, aggregates are used in granular base and subbase layers directly below the pavement surface and act as a strengthening component.

When designing a new road or pathway, particularly on poor soil

Design Recommendations and Considerations of Soil Retaining Structures

A retaining wall or structure holds soil and/or rock in its place and is generally used to prevent the erosion of soil and resist lateral earth pressure. There are many types of retaining structures including gravity, cantilever, sheet piles, anchored earth walls, etc. and are chosen based on structure and site-specific considerations.

Used for structures that experience major changes in ground elevation

Excavation Requirements and Recommendations

Excavations generally require site clearance, ‘setting out’, and safety measures. There are multiple types of excavation that depends on the site and building being constructed – manual excavations can suffice for small buildings, whereas mechanical earth cutting equipment is needed for larger buildings.

Performing test pits require excavations.

Tunnels and Buried Utility Design and Considerations

It’s important to identify the location of buried utilities and tunnels when performing any construction project. Doing so cuts project risk and saves money by avoiding any future surprise during construction. This is particularly important in busy areas with high concentrations of people and utility services.

When building a new structure in a high-infrastructure area
When building a structure intended for long term use

Groundwater Management and Dewatering Considerations

Groundwater management and dewatering are necessary whenever excavation and/or construction is occurring below the water table. Ensuring suitable dewatering methods will prevent environmental and legal liabilities.

Used in many if not all civil engineering cases.
Especially important when constructing near an aquifer.

Topographic Survey Services

Topographic survey services are important first step during the planning and schematic phase of a project. It takes into consideration local land variabilities and contours by using both observational and mechanical equipment to record and analyze the topography of an area.

This is a preliminary step for all site constructions, and is a cost efficient method of gathering important initial information.

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Developing a scope of services tailored to the project

We will contact you regarding the location, proposed project, budget, and other important information, so that we can perform a preliminary desktop site review and/or topological survey. Once this is complete, we can recommend specific subsurface exploration techniques, unique to your project.

Subsurface exploration

We will collaborate with you and decide which tests are the most suitable for your project based on our preliminary tests, the budget, and local laws and policies. We recommend test-pits for most sites due to their ability to collect a lot of information at a low cost.

Physical testing of samples

We will take the samples we collected from the subsurface exploration and analyze them in an off-site lab. This usually takes five days.

Identify foundation loading conditions

In this step, we identify the loading foundations of the structure such as the weight that will likely be put on the site. From this information, we can decide the foundation type to be used.

Preparation of a geotechnical report with recommendations

We will provide you with an exhaustive report containing our recommendations regarding your site, and schedule a time to sit down and discuss our options.

Consulting services during development

We are involved at every step of the development process in order to ensure a safe, reliable, and fluid construction.

Field Reviews

Finally, we will conduct a field review to ensure that the foundation and design have been constructed according to our recommendations.

Common Questions

We have collected the following common questions to assist you in determining the scope and requirements of the construction services you need.

What is the scope of soil engineering?

There are multiple stages in geotechnical engineering to ensure a thorough understanding of the soil conditions, and how they determine construction constraints or the stability of the structure.

The first stage is the inspection of the soil mechanics, followed by the design and engineering process, which includes site work, cost estimation, and project management, and lastly, a report with recommendations. At each stage, the specifics of the site and the project determine which services are needed. The services explained above contribute to ensuring the safety, reliability, and efficiency of any civil engineering project.

Geotechnical Services for Civil Engineering

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Contact us if you need geotechnical services for the following civil engineering scenarios: