Split Pile Foot for Load-Bearing Capacity Testing

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Solution Overview

Problem

Current methods for determining the load-bearing capacity of piles in subsoil are costly and unreliable, as they require additional reaction piles and cannot separately measure tip resistance and skin friction, leading to inaccurate data due to mutual influence and high testing efforts.

Innovation Solution

A test arrangement where the pile foot is axially displaceable relative to the pile shaft, allowing for single-pile test loading without additional reaction piles, with a hydraulic element loading the pile and displacement sensors measuring axial displacements to separately record tip resistance and skin friction, reducing costs and improving data reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pressure tests with reaction piles are used, then load-bearing capacity can be determined, but testing costs and complexity increase due to additional reaction piles and heavy loading bridges

Engineering Contradiction:
Improveload-bearing capacity determinationVSAvoidtesting arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the reaction system from external elements (reaction piles and loading bridges) and integrates it into the test pile itself through the split pile foot design. The first pile foot portion serves as the reaction element, eliminating the need for separate reaction piles and heavy loading infrastructure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pile foot is designed to serve multiple functions: it acts as both the test subject and the reaction system. The first pile foot portion provides both the reaction force for loading and the measurement surface for displacement sensors, eliminating the need for separate dedicated reaction elements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If conventional test methods are used, then load-bearing capacity can be measured, but tip resistance and skin friction cannot be determined separately

Engineering Contradiction:
Improveload-bearing capacity measurementVSAvoidseparate tip resistance and skin friction data
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The pile foot is segmented into a first portion and a second portion, with the first portion serving as the reaction element and the second portion as the measurement element. This segmentation allows separate measurement of displacements at different locations, enabling calculation of both tip resistance and skin friction components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The split pile foot design introduces an intermediary measurement system where displacement sensors measure relative displacements between the first and second pile foot portions. This intermediary measurement approach enables the separation of tip resistance and skin friction contributions to the total load-bearing capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If reaction piles are used to provide reaction forces, then tensile forces can be introduced into the subsoil, but mutual influence between reaction piles and test pile distorts measurement results

Engineering Contradiction:
Improvetensile force introductionVSAvoidmeasurement result accuracy
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The invention removes the external reaction piles from the system and replaces them with an internal reaction mechanism within the test pile itself. The first pile foot portion provides the reaction force locally, eliminating the source of mutual influence and ground disturbance caused by external reaction piles.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables cost-effective and reliable determination of load-bearing capacity by allowing separate measurement of tip resistance and skin friction, reducing testing efforts and improving data accuracy, and can be reused, specifically applicable to micropiles and displacement piles.

Implementation Method 1

a hydraulic element for tensile or compressive loads of the pile

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

displacement sensors for measuring axial displacements of the pile

Methodology Applied
Scientific EffectDisplacement sensing: Displacement

Data Source

PatentEP2295647B1Inspection method for piles
Publication Date: 2012.10.24 GRUND PFAHL & SONDERBAU
  • EP2295647B1 patent drawingFigure 1~4
  • EP2295647B1 patent drawingFigure 5

AI summary

The testing arrangement comprises a pile base (1), a pile head (17), a pile shank (3b) as exterior boundary, and a tubing shank (3a) as interior boundary. A measuring head (4) is provided, which is connected with a tubing shank. A hydraulic element (11) is provided for tensile or pressure loading of the pile. The pile base is formed axially adjustable corresponding to the pile shank. An independent claim is also included for a testing method for determining the bearing capacity in an underground.