Single-Pass Cable Trenching and Vacuum Evacuation
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Solution Overview
Problem
Existing methods for laying the 'last mile' of underground cables, such as fiber optic or electrical cables, are cumbersome and cause significant disruption in urban areas due to dense infrastructure and frequent road repairs, requiring multiple passes to cut slots for cable insertion.
Innovation Solution
A system and method involving a portable cutting and evacuating machine that cuts a void in one pass through existing surfaces, followed by immediate vacuuming, laying cables, filling the void with a non-shrinking composition, and sealing with a topping material to minimize disruption and efficiently encase the cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple passes are used to cut slots for cable insertion, then the cable can be inserted into the ground, but the construction time increases and surface disturbance is significant
Solution Approach 1:
The cutting process is segmented into a single-pass operation using a specialized cutting head that creates the complete cable pathway in one traversal, eliminating the need for multiple passes. The cutting head includes a rotating cutter that excavates and removes soil simultaneously, creating a ready-to-receive cable channel in a single operation.
Solution Approach 2:
The traditional mechanical slot-cutting method requiring multiple passes is replaced with a vacuum-assisted single-pass cutting system. The vacuum system immediately removes cuttings as the cutter progresses, allowing continuous forward motion and eliminating the need to reverse or make additional passes, thereby significantly reducing construction time.
2Productivity
If multiple passes are used to cut slots, then cable insertion is possible, but surface disturbance and neighborhood disruption increase
Solution Approach 1:
The vacuum system continuously extracts soil cuttings and debris from the cutting zone as the cutter progresses through the ground. This immediate removal of material minimizes surface disruption, prevents accumulation of debris that would require additional surface restoration work, and reduces noise and dust impact on the surrounding neighborhood.
Solution Approach 2:
The cutting and material removal operations are performed continuously in a single pass without interruption or reversal. The vacuum system operates continuously alongside the cutter, maintaining a clear pathway as it is being created, which eliminates the need for multiple passes and minimizes the overall duration of surface disturbance.
3Reliability
If a non-shrinking composition is used to fill the void, then the cable is properly encased and protected, but more material is required compared to shrinking compositions
Solution Approach 1:
The composition formulation is modified to have zero or negative shrinkage properties, meaning it maintains its volume or expands slightly during curing. This is achieved by adjusting the water-cement ratio, adding expansion agents, or using specialized grout formulations that compensate for normal shrinkage, ensuring the cable remains fully encased without voids despite the increased material quantity.
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
This approach reduces construction time, minimizes surface disturbance, and effectively encases cables with a durable, impermeable seal that withstands groundwater, allowing for seamless integration with existing surfaces and future road repairs without damaging the cables.
Implementation Method 1
cut and immediately evacuate a void in the existing covering surface
Implementation Method 2
flow a non-shrinking composition into a portion of the void around the cable to fill a portion of the void
Implementation Method 3
Upon rigidification the cable is encased in the void by the non-shrinking composition
Implementation Method 4
apply a topping material to the exposed surface of the composition in such volume as to fill any remaining portion of the void. This seals the void
Data Source
AI summary
Methods and apparatus for cutting a trench (e.g., for a fiber optic cable or wire conductors) in an existing covering surface (e.g., a road surface), wherein the trench has a depth of approximately 10 to 12 inches and a width of approximately 0.5 to 1.25 inches. Debris from the cut trench is evacuated (e.g., vacuumed) from the trench as the trench is cut. The trench may be backfilled by flowing a non-shrinking composition into at least a portion of the trench and, after hardening of the non-shrinking composition, applying a topping material to a remaining portion of the trench. In one example, the non-shrinking composition is configured to rigidify within one hour of being flowed into the trench, be substantially impermeable thereafter (e.g., having a hydraulic permeability of less than 0.0000001 cm/s upon drying), and be non-compressible and non-expanding.