Sinkholes: What They Are, Why They Happen, and the Real Cost of Ignoring Them

Sinkholes are one of the most alarming and costly ground failures a property owner, developer, or authority can face. They often appear suddenly, grow rapidly, and can escalate from a “small hole” into a major structural, safety, and financial crisis.

In Malaysia, sinkholes are becoming more frequent due to dense urban development, aging underground infrastructure, groundwater changes, and construction activities—especially on slopes and reclaimed or filled ground.

At Shinei Geotechnique, we are frequently called in to assess and stabilise sinkholes, including emergency situations involving slope failures, damaged buildings, and public safety risks. This article explains what sinkholes are, why they happen, their cascading impacts, and why early intervention is critical.

What Is a Sinkhole?

A sinkhole is a depression or collapse of the ground surface caused by the loss of subsurface support. This happens when soil or rock falls into an underground void created by erosion, leakage, dissolution, or construction-related disturbance.

Sinkholes can be:
Small, progressive ground settlements
Sudden collapses affecting roads or buildings
Deep void-related failures extending beneath structures or slopes

Common Causes of Sinkholes in Malaysia

Common Causes of Sinkholes in Malaysia
Many sinkholes in urban Malaysia are human-induced rather than purely natural.

1. Underground Pipe Leakage
Water, sewer, or stormwater pipe leaks slowly wash away fine soil particles, forming voids that eventually collapse.

2. Poorly Compacted Backfill
Utility trenches, old foundations, or abandoned structures that were inadequately compacted can fail years later.

3. Groundwater Level Changes
Lowering of groundwater due to pumping, excavation, or drought reduces soil support and accelerates collapse.

4. Construction Activities
Piling, deep excavation, tunnelling, slope cutting, or adjacent foundation works can destabilise surrounding ground.

5. Limestone / Karst Geology
In certain regions, limestone dissolves naturally, forming cavities that may suddenly collapse—especially when triggered by water flow changes.

The True Cost and Implications of Sinkholes

This is the part most people underestimate.
A sinkhole is not just a hole to be filled. It is a failure mechanism with wide-ranging implications.

1. Structural Damage to Buildings
Foundation settlement or differential movement
Cracked columns, beams, slabs, and walls
Long-term loss of structural integrity
Expensive underpinning or reconstruction works
👉 Cost implication:
Minor repairs may run into tens of thousands of ringgit; structural strengthening or underpinning can easily reach hundreds of thousands or more, depending on severity.

2. Slope Failures and Landslides
Sinkholes on or near slopes are especially dangerous. Once underground support is lost, it can trigger:
Localised slope slips
Progressive slope failure
Retaining wall collapse
Debris flow or soil movement downslope
👉 Cost implication:
What begins as a small sinkhole can escalate into full slope stabilisation works, including soil nails, anchors, shotcrete, retaining walls, and drainage systems—often costing multiple times the original repair.

3. Damage to Roads and Infrastructure
Road collapses and traffic disruption
Damage to utilities (water, sewer, power, telecom)
Emergency closures and public safety hazards
👉 Cost implication:
Beyond repair costs, there are indirect costs:
Traffic diversion
Business disruption
Emergency response expenses
Public liability exposure

4. Safety, Legal, and Liability Risks
Sinkholes pose serious risks to:
Occupants
Pedestrians and motorists
Construction workers
Property owners, developers, or contractors may face:
Legal claims
Insurance disputes
Regulatory enforcement
Reputation damage
👉 Cost implication:
Legal and liability exposure can exceed physical repair costs, especially if injuries or fatalities occur.

5. Project Delays and Business Disruption
For construction projects:
Immediate stop-work orders
Redesign of foundations or slopes
Re-approval from authorities
Contractor and consultant standby costs
👉 Cost implication:
Delays often cost more than the rectification itself, especially for time-sensitive developments.

Warning Signs You Should Never Ignore

Sinkholes rarely appear without warning. Common red flags include:

• Sudden cracks in walls, floors, pavements, or roads
• Doors or windows becoming misaligned
• Localised ground settlement or depressions
• Ponding water where it never occurred before
• Tilting fences, lamp posts, or trees
• Unusual underground water sounds
• Early detection can reduce total costs dramatically.

What to Do If You Suspect a Sinkhole

Step 1: Ensure Immediate Safety

• Restrict access
• Stop loading or construction
• Secure the affected area

Step 2: Do NOT Attempt Temporary or DIY Fixes

Uncontrolled backfilling can:

• Hide the real problem
• Increase collapse risk
• Shift voids to adjacent areas or slopes

Step 3: Engage a Geotechnical Specialist Early

Early professional assessment often:

• Limits failure extent
• Reduces total repair scope
• Prevents slope or structural escalation

What to Do If You Suspect a Sinkhole

A professional sinkhole assessment typically involves:

• Site inspection and failure mapping
• Review of utilities, drawings, and construction history
• Boreholes or probing
• Groundwater assessment
• Geophysical surveys (where required)
• The objective is to identify the failure mechanism, not just the visible damage.

Engineered Sinkhole Rectification Solutions

Depending on site conditions, solutions may include:

• Controlled pressure grouting (cementitious or chemical)
• Ground replacement and recompaction
• Micropiles or underpinning for structural support
• Drainage correction and pipe replacement
• Slope stabilisation systems (soil nails, anchors, retaining walls)

Emergency Sinkhole and Slope Failure Response

Some situations require immediate intervention, particularly when:

• Buildings are at risk
• Slopes show signs of progressive failure
• Roads or access routes are compromised
• Further collapse is ongoing

Shinei Geotechnique provides rapid-response site visits, technical assessment, and stabilisation planning for urgent cases.

Early Action Saves Money and Lives

Sinkholes are rarely isolated problems. Left untreated, they often evolve into:

• Structural failures
• Slope collapses
• Infrastructure damage
• Legal and financial crises
• Early geotechnical intervention is always cheaper, safer, and more effective than delayed reaction.

If you are dealing with:

• A sudden ground collapse
• Signs of subsidence
• Sinkholes near buildings or slopes

Act early. The cost of investigation is small compared to the cost of failure.

Need an urgent geotechnical site visit or sinkhole assessment?

Contact Shinei Geotechnique for professional evaluation, emergency response, and engineered rectification solutions.

Engineering ground you can trust.