Fluidized Sand Composition for Sinkhole Density Control
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Solution Overview
Problem
Conventional soil compaction methods, especially in areas with limestone, often result in unstable soil structures prone to sinkholes, and existing filling materials like cement grout disrupt groundwater flow and are difficult to excavate, making it challenging to achieve consistent density and stability for load-bearing purposes.
Innovation Solution
A fluidized sand composition made from graded sand, anionic polymer fluidizer, cationic polymer plasticizer, and surface active agent, allowing for controlled unit weight, fluidity, and ease of excavation, which can be injected into cavities and return to a solid state, maintaining water flow and providing soil stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement grout is used to fill sinkholes and cavities, then the cavity is filled and compaction is achieved, but groundwater flow is disturbed and future excavation becomes difficult
Solution Approach 1:
The patent uses porous expanded perlite granules as the primary filling material. These granules create a porous structure that allows groundwater to flow through the filled cavity while maintaining soil stability. The porous nature of the material prevents groundwater flow disturbance compared to cement grout, while still providing reliable cavity filling and compaction.
Solution Approach 2:
The patent employs expanded perlite granules that can be easily removed and recovered if future excavation is needed. Unlike cement grout which is difficult to excavate, the perlite granules can be discarded or recovered with minimal effort, providing flexibility for future ground modifications while maintaining current soil stability.
2Productivity
If conventional sand filling is used by excavator, then cavities can be filled, but the density of sand is inconsistent making it difficult to know how much volume is filled
Solution Approach 1:
The patent changes the physical parameters of the filling material by using expanded perlite granules with specific density characteristics (0.08-0.15 g/cm³). This standardized material parameter allows for consistent density control during filling operations, enabling accurate volume determination while maintaining high filling productivity through the material's flowable nature.
Solution Approach 2:
The patent replaces the mechanical compaction method (excavator-based sand filling) with a material-based solution using expanded perlite granules that achieve consistent density through their inherent physical properties. The granules can be filled using simple pouring or pumping methods, substituting complex mechanical compaction systems with a simpler material-driven approach that provides consistent density results.
3Reliability
If deep dynamic compaction or vibro-tamper is used to compact sandy ground, then soil compaction is achieved, but vibration causes damage to surrounding structures
Solution Approach 1:
The patent extracts the harmful vibration element from the compaction process by replacing dynamic compaction methods with static filling using expanded perlite granules. The granules achieve soil compaction and cavity filling through their physical placement and settlement rather than through vibrational forces, eliminating damage to surrounding structures while maintaining reliable soil compaction.
Solution Approach 2:
The patent uses expanded perlite granules as a disposable filling material that achieves compaction through simple placement rather than requiring expensive and structurally damaging vibration equipment. The granules provide sufficient compaction through their own weight and settlement characteristics, eliminating the need for heavy-duty vibro-tamper machinery and associated vibration damage risks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The fluidized sand composition ensures consistent density and volume control, allowing for stable soil filling without disrupting groundwater flow, facilitating easy excavation and mitigating liquefaction, while providing a controllable and stable filling material for sinkholes and cavities.
Implementation Method 1
A fluidized sand composition made from graded sand, anionic polymer fluidizer, cationic polymer plasticizer, and surface active agent, allowing for controlled unit weight, fluidity, and ease of excavation
Implementation Method 2
which can be injected into cavities and return to a solid state
Data Source
AI summary
A fluidized sand composition for use as a filling material for sinkholes and the like weakened ground cavities. The fluidized sand composition is produced by mixing graded sand, water, a fluidizer, a plasticizer, and a surface active agent. The fluidized sand composition is easily injected into the ground cavity of a sinkhole. After filling, the fluidized sand composition will return to the solid natural condition according to the effect of plasticizer previously added. The fluidized sand composition allows for compaction, soil stabilization, permits water migration through the material, and can be easily excavated.