Displacement Drill String Torque Analysis for Borehole Load Capacity

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Solution Overview

Problem

Existing displacement drilling methods are complex and costly, with limited accuracy for determining the load-bearing capacity of boreholes, often requiring additional equipment and separate exploratory devices for precise soil assessment.

Innovation Solution

A method and device that record and analyze operating parameters such as torque, penetration depth, and penetration force during displacement drilling to directly determine the load-bearing capacity of boreholes, using a load capacity index and empirical tables for precise characterization of soil conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If displacement drilling is used to determine load-bearing capacity, then the measurement precision is improved, but the device complexity increases due to additional sensors and computing devices

Engineering Contradiction:

Improveload-bearing capacity determination accuracyVSAvoiddrilling device structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The drilling device is designed to perform multiple functions: it既能钻探 boreholes又能 determine load-bearing capacity using the same drill string equipped with sensors. The drill string serves both as a drilling tool and as a measurement platform, eliminating the need for separate probing equipment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The drill string itself generates the measurement data through its own operating parameters (torque, penetration force, rotation speed) during the drilling process. The system uses self-generated data from the drilling operation to determine soil properties and load-bearing capacity without requiring external testing equipment.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If separate exploratory devices are used for soil assessment, then the measurement precision is improved, but the productivity decreases due to additional equipment and time requirements

Engineering Contradiction:

Improvesoil assessment accuracyVSAvoiddrilling efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The exploratory measurement function is merged with the drilling operation. The same drill string that creates the borehole also measures soil properties through integrated sensors, combining two previously separate operations into one unified process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The measurement process occurs continuously during the drilling operation itself. As the drill string penetrates the soil, sensors continuously record operating parameters, eliminating the need for separate intermittent testing operations and maintaining continuous productive action.

Inventive Principle:

Principle #20Continuity of useful action

3Ease of operation

If empirical factors and offsetting procedures are used for load-bearing capacity estimation, then the ease of operation is improved, but the measurement precision deteriorates

Engineering Contradiction:

Improveassessment simplicityVSAvoidload-bearing capacity accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system implements feedback by continuously monitoring drill string operating parameters during penetration and using this real-time data to determine soil properties and load-bearing capacity. The computing device processes the measured data and provides immediate feedback about soil conditions, replacing empirical estimation with actual measured feedback.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The mechanical/empirical estimation method is replaced with a sensor-based measurement system. Instead of using empirical factors and manual assessment, the system uses electronic sensors to directly measure operating parameters and a computing device to calculate load-bearing capacity, substituting mechanical estimation with electronic measurement and calculation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 simple, economical, and precise determination of borehole load-bearing capacity, reducing the need for separate exploratory devices and providing accurate soil assessments, with the ability to automatically adjust drilling based on determined soil properties.

Implementation Method 1

In the displacement area, drilled material that is present is displaced radially with respect to the drill string, forming a cavity and compacting adjacent soil areas.

Methodology Applied

Scientific EffectRadial displacement and compaction: Compression

Implementation Method 2

a drive device for rotary driving and axial displacement of the drill string

Methodology Applied

Scientific EffectRotational motion and axial displacement:

Implementation Method 3

means are provided for detecting operating parameters of the drill string when the drill string is axially driven into the ground

Methodology Applied

Scientific EffectParameter detection:

Implementation Method 4

a computing device is provided which mathematically relates the operating parameters to determine the carrying capacity of the borehole

Methodology Applied

Scientific EffectMathematical relationship between torque and penetration depth:

Data Source

PatentEP1942247B1Method and apparatus to drill in the soil by displacement

Publication Date: 2009.04.08 BAUER MASCH GMBH

Figure 1

AI summary

The method involves driving the drill string (10) in the ground (3) in a rotating manner, where the drill string has a cross sectional large displacement area (20) in its sub area. The operating parameters are detected while driving the drill string in the ground. The operating parameters are used for determining the load-carrying capacity of the drilling (1). An independent claim is also included for a device for building a drilling in the ground by displacement boring.