Jack Support Block Sinking on Soft Ground
Jack support blocks are designed to provide stability and load distribution during vehicle lifting. When operating on soft or loose surfaces, the support blocks may sink into the ground, reducing stability and increasing the risk of accidents.
1. Causes of Support Block Sinking
Soft or Unstable Ground: Soil with low bearing capacity, sand, gravel, or mud cannot support the concentrated load of the jack.
Improper Block Size or Material: Small or low-strength blocks cannot adequately distribute the load, causing them to embed into soft surfaces.
Overloading: Exceeding the rated capacity of the jack or block increases ground pressure, leading to sinking.
Uneven Load Distribution: Misaligned blocks or angled jacking can concentrate force on a small contact area, promoting penetration into the ground.
2. Effects on Lifting Performance
Reduced Stability: Sinking blocks tilt or shift, increasing the risk of vehicle slippage or jack failure.
Uneven Lifting: Differential sinking causes one side of the vehicle to lift faster than the other, potentially damaging the chassis or suspension.
Accelerated Block Wear: Repeated sinking and tilting can deform the block, reducing service life.
Safety Hazards: Operators face increased risk of injury due to sudden tilting, slippage, or block failure.
3. Preventive Measures
Ground Assessment: Always evaluate the surface before lifting; avoid soft or unstable areas when possible.
Use Load Distribution Plates: Place a wide, rigid plate or pad under the support block to spread the load over a larger area.
Select Appropriate Blocks: Use larger or higher-strength support blocks designed to distribute weight effectively on soft ground.
Load Management: Do not exceed the rated capacity of the jack and block combination.
Regular Inspection: Check blocks for deformation, cracking, or wear before use, especially when operating on uneven or soft surfaces.
4. Conclusion
Support block sinking on soft ground is primarily caused by low soil bearing capacity, improper block selection, overloading, and uneven load distribution. Proper surface assessment, use of load distribution plates, appropriate block selection, and careful lifting practices are essential to ensure safety and maintain block integrity.
References
Gent, A. N. Engineering with Rubber: How to Design Rubber Components. Hanser Publishers, 2012.
ASTM D2000 – Standard Classification System for Rubber Products in Automotive and Industrial Applications.
Lake, G. J. “Fatigue and Fracture of Elastomers.” Rubber Chemistry and Technology, 2000.
ISO 2230 – Rubber Products—Guidelines for Storage and Maintenance.
ISO 7619-1 – Rubber, Vulcanized or Thermoplastic — Determination of Indentation Hardness.
