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department of geotechnical & foundations

Geotechnical & foundation failure analysis.

Ground failures rarely look inevitable in hindsight and almost never announce themselves in advance. We determine what happened beneath the surface — independently, and to a standard that holds up in court.

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What failed?

Start a conversation with our AI Research Concierge, already scoped to geotechnical & foundations. Select a specialization to prompt it, or describe your situation directly.

AI Research Conciergegeotechnical & foundations · triage, not a substitute for an expert
Tell me what happened and I'll help scope it — the likely mechanisms, what to preserve, and which expert fits. I won't give the formal analysis here.

Ground failures are unusually easy to misdiagnose from the surface. A levee breach, a collapsed trench, a cracked foundation, and a landslide can all look, at first glance, like some vague version of "the soil gave way." They are not the same event. Each traces to a specific mechanism operating below grade: a piping channel through an embankment, an unsupported trench wall exceeding its angle of repose, a clay layer consolidating under new load, a slip surface that has been there since before the structure was built. This department covers the ground-failure modes where soil, rock, and water interact, from a breached levee down to a sinkhole a few feet across.

specialization areas

Specialization areas in this department.

Each specialization area covers a distinct ground-failure mechanism with its own physics, examination protocol, and governing standards. Start with the one that matches your incident.

methodology

How this department investigates.

Geotechnical investigations are sequenced to preserve subsurface evidence before it is disturbed, backfilled, or repaired. Surface documentation always precedes intrusive work.

Geophysical subsurface imagingGround-penetrating radar, electrical resistivity, and seismic methods to locate voids, seepage paths, and failure surfaces without excavation.
Subsurface exploration & samplingBorings, test pits, and cone penetrometer testing to characterize soil and rock stratigraphy at and around the failure.
Laboratory soil & rock testingIndex, strength, consolidation, and permeability testing on recovered samples to quantify the properties that governed the failure.
Instrumentation & monitoring reviewPiezometer, inclinometer, and survey-monument records establishing the movement history before and after the event.
Stability back-analysisLimit-equilibrium and finite-element modeling calibrated to as-found conditions to identify the governing failure mechanism.
Design & construction records reviewGeotechnical reports, as-built drawings, and compaction and inspection records assessed against the applicable code and standard of care.
news & insights

News & insights from this department.

Technical briefings and case analyses on dam, levee, excavation, foundation, and slope failures — written by the people who investigate them.

When a breach destroys its own initiation zone

The place where an embankment failure started is the first thing the breach flow carries away. Instrumentation records, inspection history, construction files and the surviving geometry have to carry the reconstruction.

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Overtopping, spillway capacity and the design flood question

An overtopping failure is rarely just a big storm. It is a comparison between the flood that arrived, the outlet capacity that was available, and the design basis the structure was built to.

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Internal erosion: four mechanisms and the filter question

Seepage through an embankment is normal. Soil moving with the seepage is not. Backward erosion, concentrated leaks, suffusion and contact erosion are distinct mechanisms with distinct evidence.

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What survives after the trench is backfilled

Rescue and public safety mean a collapsed trench is usually gone within hours. What is left to reconstruct it: photographs, spoil and wall samples, the shoring hardware, and the day's records.

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Surcharge, vibration and water: loads from outside the trench

A trench wall can fail without the soil in it being any weaker than assumed. Spoil, equipment, traffic vibration, seepage and adjacent excavation all add load the protective system never accounted for.

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Soil classification governs everything downstream

Slope angle, shoring selection and shield rating all follow from one field judgment: what type of soil this is. How that class is set, and why it does not stay true for the life of the trench.

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common questions

Geotechnical failure analysis — the questions we hear.

How do you determine which ground-failure mechanism actually caused this?

By working from physical evidence rather than the incident description. A cracked foundation, a leaning wall, and a collapsed trench each have a governing soil mechanism behind them — consolidation, lateral earth pressure, internal erosion, loss of shear strength — and each leaves a distinguishable signature in the subsurface, the failure geometry, and the monitoring record. Subsurface investigation, laboratory testing, and back-analysis modeling identify which mechanism is consistent with what is actually observed, not which one is assumed.

What should be preserved at a geotechnical failure site before it is repaired?

As much of the as-failed condition as safety allows: the failure surface or breach geometry, any exposed soil or bedrock, instrumentation and monitoring data, and construction and design records. Backfilling, grouting, regrading, or re-vegetating before documentation removes the physical evidence a forensic investigation depends on — often permanently, since the subsurface condition that caused the failure cannot be reconstructed from photographs alone.

Which standards and codes apply to geotechnical failure investigations?

It depends on the failure. Embankment dams and levees are commonly evaluated against USACE engineering manuals and state dam-safety program requirements; excavations against OSHA 29 CFR 1926 Subpart P; retaining walls against AASHTO LRFD and, for segmental walls, NCMA design guidelines; and soil characterization across all of these areas relies on ASTM test methods for classification, compaction, strength, and consolidation. Local and state building codes typically govern foundation design.

Can you distinguish a design defect from an unforeseeable subsurface condition?

Usually, yes. Design adequacy is evaluated against the geotechnical information that was reasonably available at the time — borings, published geologic mapping, and standard practice — while the actual failure mechanism is established independently from post-failure investigation. When the failure mechanism is one the original geotechnical report should have identified and addressed, that points toward a design or investigation deficiency; when it involves a condition outside what reasonable due diligence would have found, it points elsewhere. That comparison is usually the central question in these disputes.

Ground gave way. Find out why.

Describe what happened. We will scope it and connect you with the right expert — usually within one business day.

failure-analysis assistanttriage · not a substitute for an expert
Tell me what happened and I'll help scope it — the likely mechanisms, what to preserve, and which expert fits. I won't give the formal analysis here.