Shoring and Excavation Design
Shoring is needed when there isn’t enough space to safely slope an excavation, typically near property lines, roads, utilities, or existing buildings. It’s also required where ground movement from construction works could damage adjacent structures, or where soil or groundwater conditions reduce excavation stability. In these cases, engineered and feasible shoring systems are used to control soil movement, protect workers and infrastructure, and prevent excavation collapse.
We start by defining the excavation geometry based on the proposed works, adjacent structures, and site constraints, then build a subsurface and groundwater model using data from our geotechnical investigation, typically test pits, boreholes with Standard Penetration Tests (SPT)/Dynamic Cone Penetration Tests (DCPT), and targeted lab testing.
We select the analysis approach based on site conditions and design stage:
Groundwater is addressed early. If dewatering is feasible, we design safe drawdown systems or provide instructions for gravity drain systems; if not, we use cut-off methods such as secant or tangent piles, soil mixing, or jet grouting integrated with the support system.
Our design drawings focus on construction details that contractors and clients rely on for permit application, tender, and construction. Typical details include: excavation sequencing, anchor and shotcrete details, waler and strut elevations, raker forces and reactions, test and lock-off loads, and field review requirements that keep the dig moving safely and efficiently.
In the Lower Mainland and many parts of British Columbia, shotcrete and anchor shoring is often the most cost-effective and practical method for deep excavations. However, when property-line anchors are not permitted due to lack of encroachment agreements, alternative systems are required.
We specialize in non-encroaching shoring solutions tailored to tight urban sites and sensitive boundaries. These include:
Where tieback anchors are allowed, we also design anchored and hybrid systems to match site logistics and construction sequencing.
When excavations extend immediately below an adjacent footing or structure, we design and sequence underpinning shoring systems that maintain support entirely from within your site and limit settlement of existing structures. Common solutions include:
When underpinning, minimizing movement is key. Each system is managed with a settlement management plan that defines and includes fixed survey points, and/or instrumentation such as inclinometers, vibration monitors, and piezometers, movement thresholds, and monitoring frequency and review.
Sites with high groundwater require effective seepage control to protect neighbouring subgrades and comply with municipalities groundwater discharge requirements. We design and recommend dewatering systems such as wellpoints and weepholes, help coordinate temporary discharge approvals, and select cut-off or control methods based on site conditions. These may include secant or jet-grouted walls for full-depth cut-off, press-in sheet piles for low-vibration installations, or top-down shoring/basement wall construction where the permanent wall serves as both temporary shoring support and seepage barrier. When feasible where conventional shoring is used, we recommend design of tanked raft slab and sandwhich slab foundations with integrated waterproofing.
We plan, monitor, and perform anchor testing, including proof and performance tests, lock-off and creep measurements, so design assumptions are confirmed against actual conditions on your site. This direct testing lets us use a less conservative soil model for design of the shoring and excavation to achieve the same performance with less construction cost, for example better investigation and more stringent testing allows for shorter bond lengths, fewer or lighter anchors, and leaner bracing where justified translating into lower construciton costs. Field reviews verify capacities and sequencing, and if conditions vary you receive prompt memo updates with clear next steps so the excavation does not stall. We set movement limits appropriate to the surroundings and verify them with instrumentation including inclinometers, load cells, piezometers, survey points, and vibration monitors.
Excavation and shoring often intersect with municipal ESC requirements. We prepare site-specific ESC plans that address offsite sediment control, runoff, stockpile management, and water treatment during construction. Our team provides monitoring and reporting to confirm compliance with municipal bylaws and provincial regulations, helping contractors avoid delays, fines, or stop-work orders. By integrating ESC inspections with other field reviews such as shoring anchor testing or foundation subgrade checks, we streamline site visits, reduce inspection costs, and keep projects moving while protecting surrounding infrastructure and waterways.
You’ll receive a permit-ready design package that includes drawings, site plans, excavation elevation views, wall sections, construction sequencing, acceptance criteria, and detailed notes on excavation, shoring, and underpinning, suitable for tender, permitting, and construction.
A supporting calculation and engineering memo documents key design assumptions, analysis methods, predicted wall movements and loads, and the groundwater control strategy, including contingencies.
During construction, we provide ongoing support through RFI responses, coordination with the consulting team, owner, and contractor, and field reviews as required to fulfill our Letters of Assurance and project commitments.
