How to fix a sinkhole. A sinkhole in the ground.

How to Fix a Sinkhole: Sinkhole Repair 

Water Restoration

Where there’s unstable ground, there’s a sinkhole! They can occur due to natural causes such as erosion or even human activity like construction. Regardless of their formation, knowing how to fix a sinkhole quickly and correctly is essential to protect your property and prevent further damage. Keep reading to learn more about how sinkholes are created and find out what you can do to fix them.

What Is a Sinkhole?

A sinkhole is a geological phenomenon characterized by a sudden and dramatic collapse of the Earth’s surface, resulting in a depression or hole in the ground. Sinkholes typically occur in karst terrain and form when underground water dissolves soluble rocks such as limestone, gypsum, or salt beds, creating cavities or voids beneath the ground surface. Over time, the weight of the overlying sediment or rock becomes too much for the ground, leading to a collapse and the formation of very large sinkholes.

Two common types of sinkholes are cover collapse sinkholes and cover subsidence sinkholes. While both types result in the formation of sinkholes, they differ in their underlying causes and the nature of their collapse.

  • Cover Collapse Sinkholes. Cover collapse sinkholes are typically the most dramatic and dangerous type. This type of sinkhole develops due to heavy rainfall or prolonged drought that weakens the ground structure, allowing it to collapse rapidly when under sufficient stress. These sinkholes can form suddenly and without warning, causing significant damage or endangering human lives.
  • Cover Subsidence Sinkholes. Cover subsidence sinkholes are characterized by a gradual and progressive settling of the surface rather than a sudden collapse. The subsidence occurs as the underground material erodes or dissolves, causing the overlying sediment or rock layers to sink or settle gradually.

Sinkholes can vary in size and depth, ranging from a few feet to hundreds of feet across. They can occur gradually, with the ground surface sinking slowly over time or developing suddenly, causing significant damage. 

They may appear as shallow depressions or open up to become deep craters, posing a severe threat to infrastructure, buildings, and even human lives. It is important to note that sinkholes are natural occurrences, and while they can be unpredictable and potentially dangerous, they are relatively rare.

Why Do Sinkholes Occur?

Sinkholes can occur due to various geological and human-induced factors. Here are some common reasons why sinkholes may form:

  • Dissolution of soluble rocks. Sinkholes often occur where the underlying bedrock comprises soluble rocks such as limestone, gypsum, or dolomite. Over time, water percolating through the ground surface dissolves these rocks, creating underground cavities. As the holes grow more prominent, the overlying soil or sediment can collapse, forming a sinkhole.
  • Underground water erosion. Underground water sources, such as aquifers or underground streams, can erode the surrounding rocks and create voids. If the overlying soil or sediment is not strong enough to support its weight, it can collapse and form a sinkhole.
  • Changes in water levels. Fluctuations in water levels, such as heavy rainfall or changes in groundwater levels, can increase the risk of a sinkhole appearing. Excessive water can infiltrate the ground and dissolve soluble rocks more rapidly, crippling the supporting structures and potentially leading to a sinkhole collapse.
  • Homeowner action. Sinkholes on private property are the homeowner’s responsibility. Insurance may cover an evaluation and the repair if it is a sinkhole and not a subsidence incident—an artificial problem caused by things like collapsed or broken sewer pipes and drainpipes, broken septic tanks, buried trash, or soil that wasn’t correctly compacted after excavation work. 
  • Human activities. Certain human activities can contribute to sinkhole formation. For example, excessive groundwater pumping for agriculture or municipal water supplies can lower the water table, destabilizing and collapsing underground cavities. Mining operations, particularly in areas with soluble rocks, can weaken the ground and increase the likelihood of sinkholes.
Two construction works at a construction  site.
Mining increases the risk of a sinkhole.
  • Subsidence. Natural processes and human activities that cause the ground to sink or settle can lead to sinkholes. This can occur due to the compaction of loose sediments, organic material consolidation, or underground mines or tunnels collapsing.
  • Construction and development. Improper construction practices, particularly in areas with weak or soluble soils, can increase the risk of sinkholes. If the underlying soil or rock does not adequately support the weight of a structure, it can lead to localized collapse and the formation of a sinkhole.
  • Natural geological processes. Natural geological events such as earthquakes, landslides, or volcanic activity can trigger sinkholes. These events can create sudden changes in stress distribution within the ground, causing compromised areas to buckle and sinkholes to form.

The formation of sinkholes is a complex process influenced by various factors. While certain regions are more prone to them, it is difficult to predict their occurrence with certainty. Monitoring and geotechnical studies are necessary to identify and manage sinkhole risks in susceptible areas.

How to Fix a Sinkhole

A sinkhole repair must be the highest priority in cases where sinkholes have already formed. Depending on the size and depth of the sinkhole, numerous techniques may be employed to restore stability and integrity to the affected area. 

Here are some general steps to address sinkholes:

  • Ensure safety. If you notice a sinkhole forming or an existing one on your property, prioritize your safety and the safety of others. Keep a safe distance from the sinkhole and barricade the area if necessary.
  • Contact authorities. Inform your local authorities, such as your municipal or county government, about the sinkhole. They can provide guidance, assess the situation, and coordinate necessary actions.
  • Consult a professional. Contact a geotechnical engineer or a company specializing in sinkhole repair. They have the expertise to evaluate the sinkhole, determine the underlying causes, and recommend appropriate solutions.
A geotechnical engineer at work feeling the terrain.
A geotechnical engineer can help with sinkhole repair in karst terrain.
  • Assess the sinkhole. The professionals will thoroughly assess the sinkhole’s size, depth, and underlying geological conditions. They may use techniques like ground penetrating radar or drilling to gather data.
  • Stabilize the area. Depending on the size and severity of the sinkhole, stabilization measures may be required to prevent further collapse. This can involve injecting grout or other stabilizing materials into the ground to stabilize the surrounding soil.
An orange arrow directs you to the left lane to avoid a sinkhole.
Blocking off a sinkhole ensures the safety of those around it. 
  • Fill the sinkhole. Once the area is stabilized, the sinkhole can be filled with suitable materials to restore the surface. The materials will depend on the area’s geology and the professionals’ recommendations.
  • Address the underlying cause. Identifying and addressing the underlying cause of the sinkhole can prevent future occurrences. This could involve repairing broken or leaking pipes, improving drainage systems, or addressing other factors contributing to the formation of sinkholes.

Remember, sinkhole repair is a complex process that requires expertise and professional guidance. Always consult with qualified professionals who can assess the situation accurately and provide appropriate solutions based on the specific circumstances.

How to Prevent Sinkholes

Now that we know what causes sinkholes and how to repair them, how do we prevent them from forming? Here are some ways to reduce the risk of large sinkholes:

  • Conduct thorough geotechnical surveys. Comprehensive geotechnical surveys must be carried out before starting any construction or development projects. These surveys involve assessing the area’s soil composition, stability, and potential vulnerabilities by identifying areas prone to sinkholes so appropriate preventive measures can be implemented.
  • Establish building codes and regulations. Developing and enforcing strict building codes and laws ensures structures are constructed on stable ground. These codes should consider soil stability, water drainage, and potential sinkhole risks. Adherence to these regulations will minimize the likelihood of building on an unstable foundation and help prevent sinkhole-related accidents.
  • Implement proper water management. Excessive groundwater accumulation significantly contributes to a sinkhole. Implementing effective water management strategies can help prevent sinkholes. Sound drainage systems, including stormwater management infrastructure, should be designed and maintained to avoid water pooling in vulnerable areas. Inspecting and maintaining pipes, sewers, and drainage channels can minimize water-related risks.
  • Preserve and protect natural water sources. Protecting natural water sources, such as rivers, lakes, and aquifers, is essential for sinkhole prevention. Unregulated extraction of groundwater can lead to subsidence and the formation of sinkholes. Implementing sustainable water management practices, including responsible usage and monitoring, helps maintain the natural water balance and reduce the chances of sinkholes. 
A woman kayaking in the middle of lake with mountains in the background.
Protecting our oceans is important to keep the ground from shifting.
  • Educate and raise awareness. Community and public awareness about sinkholes and their prevention are crucial. Public outreach programs can inform residents about the warning signs of sinkhole formation, how to report potential sinkholes and the importance of responsible land management. This knowledge empowers individuals to take appropriate actions and contribute to prevention efforts.
  • Monitor groundwater levels. Monitoring groundwater levels can detect changes that could indicate sinkhole creation. Continuous monitoring using sensors and remote sensing techniques can pinpoint areas with excessive groundwater or abnormal water level fluctuations. Early detection allows for timely intervention to prevent further ground subsidence.
  • Implement remediation techniques. Enforcing remediation techniques can help stabilize the ground and prevent sinkhole formation in areas prone to sinkholes. These techniques include grouting, which involves injecting materials into the ground to fill voids and strengthen the soil, and compaction grouting, which densifies loose soil. These methods reinforce the environment, making it less susceptible to collapse.
  • Proper land management. Responsible land management practices prevent sinkholes. Avoiding excessive land grading, ensuring adequate soil compaction during construction, and preserving natural vegetation is essential. By maintaining the natural integrity of the land, the risk of sinkhole formation can be reduced.

Governments, developers, and communities must work together to create a safer environment and protect against the potential dangers posed by sinkholes.

Get Help from PuroClean for Sinkhole Damage!

A sinkhole is a serious concern that can damage your property and should not be taken lightly. The sudden collapse of land can lead to significant structural damage, endangering your home’s foundation and other structures. In such a dire situation, taking immediate action to minimize the impact is crucial. If you encounter property damage, contact PuroClean immediately. 

PuroClean is a trusted and reliable restoration company that handles all types of property damage. Our team of highly trained professionals understands the urgency and sensitivity of these situations and responds promptly to assess and mitigate the damage. With our advanced equipment, industry expertise, and commitment to quality, we ensure a thorough restoration process, bringing your property back to its pre-damage condition. To schedule an appointment with your nearby PuroClean office, visit our website or call (800) 775-7876. 

Last edited on 22nd of February 2024