Helical Pile Reinforced Secant Shoring Walls
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Solution Overview
Problem
Existing pile systems, such as tangent and secant walls, face challenges in high groundwater areas and deep excavations, where forming bore holes is difficult, and helical piles alone are insufficient for reliable shoring due to soil conditions, necessitating improved methods for constructing shoring walls.
Innovation Solution
A method involving a combination of tangent concrete piles and helical piles, where 10% to 50% of the tangent concrete piles are cast around a helical pile shaft, with the helical piles set deep into the ground to increase resistance, allowing for effective shoring without deep bore hole excavation in water-saturated soils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tangent walls are used with concrete piles in high groundwater areas, then the shoring wall can be constructed, but forming bore holes of sufficient depth becomes difficult due to water-saturated ground material
Solution Approach 1:
The patent combines two different pile types (tangent concrete piles and helical piles) into a hybrid shoring wall system. The helical piles are installed in water-saturated soils where traditional bore holes cannot be formed, while tangent concrete piles provide structural integrity in drier zones, creating a complementary system that overcomes the limitations of each individual pile type.
Solution Approach 2:
The patent changes the installation method parameter from traditional bore hole drilling to helical pile rotation and advancement. By changing how the piles are installed (from drilling to screwing), the system can successfully penetrate water-saturated ground materials that would otherwise prevent bore hole formation.
2Ease of manufacture
If helical piles are used alone for shoring, then installation is simplified without deep bore hole excavation, but the piles are insufficient for reliable shoring in deep excavations due to soil conditions
Solution Approach 1:
The patent merges helical piles (easy to install) with tangent concrete piles (reliable for deep support) to create a hybrid system that achieves both ease of installation and structural reliability. The helical piles provide quick installation in difficult soils, while the tangent concrete piles provide the necessary structural strength for deep excavations.
Solution Approach 2:
The patent creates a composite pile wall system combining two different pile materials and installation methods. The helical steel piles and concrete tangent piles work together as a composite structure, each contributing their strengths to achieve reliable shoring that neither pile type could provide alone.
3Reliability
If secant walls with overlapping piles are used, then watertightness and stiffness are improved, but the construction process becomes more complex requiring drilling through primary piles
Solution Approach 1:
The patent applies local quality by placing helical piles specifically in zones where water-saturated soils prevent proper bore hole formation, while using traditional tangent concrete piles in drier zones. This localized approach provides watertightness and structural integrity only where needed, rather than requiring the complex overlapping structure of secant walls throughout the entire wall.
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 enhances the stability and watertightness of shoring walls, enabling reliable excavation support in challenging soil conditions without the need for deep bore hole excavation, particularly in high groundwater areas.
Implementation Method 1
the helical flights penetrate into the soil and advance the pile directly into the earth without augering
Implementation Method 2
the pile is rotated about its longitudinal axis such that the helical flights penetrate into the soil and advance the pile
Data Source
AI summary
A pile shoring wall includes tangent concrete piles that are formed in the ground at an excavation site. The tangent concrete piles include a plurality of a first type of concrete piles in the ground at depths wherein the average depth is d1 and a plurality of a second type of concrete piles. The second type of concrete piles includes 10% and less than 50% of the tangent concrete piles, and each have a shaft of a helical pile secured therewithin. Each helical pile has a bottom portion with helical flights for screwing the helical pile into the ground, and each helical pile is set into the ground to a depth of at least about 2 m below d1. The helical flights of each helical pile are exposed to the surrounding soil and increase resistance below an excavation depth when the site is excavated.