Services · Engineering · Geotechnical design
Geotechnical Design and Shoring Design: Buildable, Economical Solutions
Geotechnical design for a deep excavation means designing the system that will hold the ground and neighbouring buildings safely. Our geotechnical design partner prepares the designs; we add our site experience on system choice, buildability and cost.
Prepared by
Our geotechnical design partner
Scope
Shoring, piled foundations, ground improvement
Our input
Buildability and cost
Inputs
Site investigation, architectural and structural design
Outputs
Calculation report and construction drawings
Region
Türkiye and Central Asia
What is geotechnical design for shoring?
Shoring design is the design of the temporary or permanent system that holds the ground, groundwater and neighbouring buildings during a basement excavation. The design also covers the system type, element sizes, excavation stages and the monitoring plan.
Our geotechnical design partner prepares the design. Meanwhile we think from the start about how it will work on site: where the rig will go in, in what order the dig will advance, and whether an anchor will pass under the neighbouring plot. This way the system on paper also works on site.
Choosing a system in geotechnical design
Excavation depth, ground, groundwater and neighbouring buildings together decide the system. On most projects we also combine more than one system.
| System | When we choose it | What to watch |
|---|---|---|
| Cantilever pile wall | Shallow cut, firm ground | Movement at the top of the wall |
| Anchored wall | Deep cut, neighbours close by | Anchors passing under the neighbouring plot |
| Propped wall | Narrow cut, or anchors not possible | Struts getting in the way of the dig |
| Soil nail wall | Suitable ground, no water | Distance to neighbouring buildings |
| Secant piles or jet grouting | High groundwater | Cut-off and base sealing |
How do we prepare a shoring design?
We prepare a shoring design in five steps. At every step we also bring in the views of the construction team.
- Data collection: We gather the site investigation, the architectural and structural designs, and details of neighbouring buildings.
- System choice: We compare several options for cost, time and risk.
- Calculations: Our design partner runs the stability, force and displacement calculations.
- Construction drawings: The drawings show the piles, anchors, waler beams and excavation stages.
- Monitoring plan: The plan sets measuring points and limit values for the wall and neighbouring buildings.
The most common problem we see: a design that cannot be built on site. For example, a bench too narrow for the rig, or an anchor angle that runs into a neighbour’s foundation. That is why we also check the design through a contractor’s eyes.
Ways to reduce cost through geotechnical design
The design stage often sets the cost of shoring. However, there are fair ways to cut cost without compromising safety.
- Using correct soil parameters so that piles and anchors are not longer than needed
- Optimising the number of anchor rows and the pile spacing
- Mixed solutions, such as soil nails above and an anchored wall below
- Setting the excavation and construction sequence to suit the programme
We review these proposals with our design partner. The designer, however, always makes the final decision.
What do you need for a geotechnical design quote?
The size, depth and complexity of the excavation set the design fee. Even so, the documents below are enough for a quote.
- Site investigation report
- Architectural design: site plan, number of basement levels and sections
- Structural design and foundation plan
- Details of neighbouring buildings and services
Also, if you have no site investigation yet, we can plan one with our drilling partner.
Frequently asked questions about geotechnical design
We have grouped the questions we receive by who asks them. If yours is not here, call us or write through the quote form.
Owners and architects
When do you need a shoring design?
You need one when the excavation gets deep and could affect a neighbouring building, a road or services. So the design should be ready before excavation, during the permit process.
Who prepares the shoring design?
Our geotechnical design partner prepares the design. We contribute on buildability, cost and the construction sequence.
How much basement space does shoring take?
The wall takes up its own thickness plus a construction tolerance. That is why the wall thickness should be settled at the concept design stage.
Are shoring and foundations in the same design?
They are usually separate designs, but they must work together. For example, a pile wall can also serve as the outer formwork for the basement wall.
Contractors and project managers
How long does the design take?
In general, the size of the excavation and how ready the data are set the time. For example, the process moves faster when the site investigation and architectural design are complete.
Can the design change on site?
If we meet unexpected ground while drilling, we tell the designer, and the design is revised if needed. That is why we record site observations every day.
Why should monitoring be part of the design?
Measurements show whether the wall and neighbouring buildings behave as calculated. Also, if movement goes past the limit values, monitoring buys time to take action.
Designers and supervising engineers
Which codes and standards apply?
For design, the designer follows TBDY 2018 and Eurocode 7. On site, we work to standards such as EN 1536, EN 1537 and EN 14490, which Türkiye adopts as TS EN standards.
What sets the displacement limit?
The sensitivity of neighbouring buildings and services sets the limit. For example, next to a sensitive building you need a stiffer system and tighter limits.
Academics and students
What are active and passive earth pressure?
Active pressure develops as the wall moves towards the excavation. Passive pressure, on the other hand, is the resistance that develops as the embedded part of the wall pushes into the ground.
What is base heave in an excavation?
In soft clay, for example, the base of the excavation can heave as soil moves in from under the wall. So deep excavations need a separate check of base stability.
Sources
Contact us about geotechnical design
Send us your site investigation and architectural design. We will plan the right system and the design process with our partner.