PHC Pipe Cased Pile Drilling with Hydraulic Hammer
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Solution Overview
Problem
Drilling with prestressed high strength concrete (PHC) pipe cased piles faces inefficiencies when dealing with hard rock strata, as traditional drill bits struggle to penetrate, leading to reduced construction efficiency and potential pile defects due to vibration-induced cracking.
Innovation Solution
A drilling apparatus featuring a PHC pipe cased pile with a hammer element and through holes, where fluid circulation is used to scour rock and soil, combining hydraulic and impact forces to effectively drill through harder rock strata, and reinforcing structures are optionally included to prevent structural damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional drill bit is used for drilling with PHC pipe cased pile, then the construction quality and efficiency can be guaranteed for soft rock strata, but the drilling efficiency decreases significantly when encountering hard rock strata due to the inability to effectively crush the rock
Solution Approach 1:
The patent replaces the traditional mechanical drill bit system with a hydraulic hammer element system. The hydraulic hammer element utilizes high-pressure water jet technology to erode and crush hard rock strata, substituting the mechanical crushing mechanism with a hydraulic erosion mechanism that is more effective for hard rock drilling while maintaining construction quality.
Solution Approach 2:
The patent introduces a hydraulic hammer element that uses high-pressure water jets to drill through hard rock. The hydraulic system delivers intense water pressure through the hammer element to erode the rock stratum, enabling effective drilling in hard rock conditions where traditional mechanical drill bits fail, thus improving drilling efficiency without compromising construction quality.
2Strength
If vibration is applied to sink the pile and compact the bottom dregs to increase bearing capacity, then the bearing capacity of the pile tip is improved, but cracks occur in the pile leading to constructional quality defects
Solution Approach 1:
The patent replaces the mechanical vibration method with a hydraulic jet method for compacting bottom dregs and increasing bearing capacity. High-pressure water jets are directed at the pile tip and surrounding soil to densify the soil and compact dregs without inducing mechanical vibrations that could crack the PHC pipe, thereby improving bearing capacity while maintaining construction quality.
3Strength
If the pile bearing stratum is soft rock, then the pile has excellent vertical resistance to static load, but the rock body provides limited resistance to the pile tip and limited ability of sinking controlling
Solution Approach 1:
The patent uses high-pressure water jets from the hydraulic hammer element to improve sinking controllability in soft rock conditions. The water jets can be directed to control the sinking process, erode soil at the pile tip to facilitate sinking, and provide real-time feedback on soil conditions, thereby enhancing operational control while maintaining the excellent vertical resistance provided by soft rock bearing strata.
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 apparatus enhances drilling efficiency and bearing capacity by effectively crushing soft rock and bonding with harder rock, improving the quality and stability of the pile foundation.
Implementation Method 1
a localized hydraulic force will be induced in the fluid contained in the drilling section of the PHC pipe cased pile by a sharp rise in the fluid pressure in addition to the impact force directly acted on the rock and soil by the hammer element
Implementation Method 2
the impact force directly acted on the rock and soil by the hammer element
Data Source
AI summary
Provided is a drilling apparatus, comprising a PHC pipe cased pile having a drilling section for containing fluid and a hammer element arranged inside the cavity of the PHC pipe cased pile which moves along the drilling direction till the bottom of the drilling section. As the hammer element moves along the drilling direction till the bottom of the drilling section, a localized hydraulic force will be induced in the fluid contained in the drilling section of the PHC pipe cased pile by a sharp rise in the fluid pressure in addition to the impact force directly acted on the rock and soil by the hammer element. Under action of the hydraulic force and the impact force, the surrounding soft rock stratum could be crushed and the rock stratum with higher strength is left intact, that is, the drilling apparatus proceeds until harder rock. At this point, concrete casting will bond with the harder rock, resulting in a better bearing capacity of the PHC pipe cased pile foundation.