Non-destructive Anchorage Depth Detection Using Impact Vibration
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Solution Overview
Problem
Existing methods for testing the effective anchorage depth of fully grouted anchor bolts are either destructive or unable to accurately measure the anchorage length, posing challenges in geotechnical engineering.
Innovation Solution
A non-destructive testing method involving multiple impacts on the anchor bolt's extended section to generate different accelerations, using accelerometers at various depths to determine stable or vibrating acceleration values, indicating adherence to the rock, and applying a gradually increasing axial force to assess effective anchorage length without damaging the anchor bolt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If over-coring method is used to test anchoring quality, then testing accuracy is improved, but the anchor bolt is damaged and needs to be replaced
Solution Approach 1:
The patent replaces the mechanical over-coring testing method with an acoustic emission detection system. Accelerometers and acoustic emission sensors mounted on the anchor bolt detect vibration signals and acoustic waves generated during impact loading, enabling non-destructive assessment of anchorage quality through signal analysis rather than physical destruction.
Solution Approach 2:
The patent introduces acoustic emission sensors and accelerometers as intermediary detection devices. These sensors act as mediators between the anchor bolt system and the testing apparatus, capturing mechanical responses (vibrations, acoustic waves) during impact loading and converting them into measurable electrical signals for analysis, thereby enabling indirect non-destructive testing.
2Object-affected harmful factors
If traditional non-destructive testing methods using ultrasound or acoustic emission are used, then the anchor bolt is not damaged, but the anchorage length cannot be accurately measured
Solution Approach 1:
The patent applies mechanical vibration through controlled impact loading on the anchor bolt head. By impacting the anchor bolt with a hammer and analyzing the resulting vibration signals captured by accelerometers and acoustic emission sensors, the system determines anchorage length based on the propagation characteristics of mechanical waves through the bonded interface, achieving accurate measurement without damage.
Solution Approach 2:
The patent employs periodic impact loading (multiple controlled hammer impacts) to excite the anchor bolt system. By applying repeated periodic mechanical impulses and analyzing the consistent response patterns across multiple impacts, the system achieves reliable and accurate determination of anchorage length through statistical analysis of the vibration and acoustic emission signals.
3Measurement precision
If multiple sensors are installed along the anchor bolt to measure accelerations at different depths, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the anchor bolt into multiple measurement zones along its length, with accelerometers and acoustic emission sensors positioned at different depths (e.g., 0.5m, 1.0m, 1.5m from the head). This segmentation enables depth-resolved measurement of acceleration and acoustic signals, allowing determination of the anchorage length by identifying where signals transition from stable (bonded) to unstable (unbonded) characteristics.
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 method allows for accurate, non-destructive evaluation of anchorage quality, ensuring higher structural reliability and ease of site implementation with lower costs, as it differentiates between effective and ineffective anchorage lengths without damaging the anchor bolt.
Implementation Method 1
impact an end of an extended section of an anchor bolt for multiple times with different amplitudes, so as to enable the anchor bolt to generate different accelerations
Implementation Method 2
acquiring accelerations at different depths of the anchor bolt by using several accelerometers that are disposed at the different depths along the anchor bolt
Data Source
AI summary
The present invention relates to a method and an apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt, which are applicable in geotechnical engineering. The method provided by the invention is for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt; the method is convenient to operate, non-destructive to an anchor bolt, and capable of testing an anchorage length of the anchor bolt. The present invention further provides an apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt. The apparatus has a simple structure, is convenient to install, and is capable of measuring an anchorage length of an anchor bolt without damaging the anchor bolt.