Portable Soil Shear Testing Device Using Dial Penetrometers
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Solution Overview
Problem
Existing laboratory direct shear test machines are large, heavy, expensive, and immobile, introducing errors due to carriage friction, and require transporting soil samples to a remote location for testing, which is time-consuming and costly, especially in construction sites where different soil types may be encountered at various depths.
Innovation Solution
A portable, lightweight (less than 1 pound) soil testing device using two commercially available dial pocket penetrometers to apply and measure compression and shear forces, allowing for on-site testing of soil samples without electricity, enabling quick evaluation of soil conditions and reducing costs by eliminating the need for expensive machinery and waiting for test results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing laboratory direct shear test machines are used, then measurement precision is improved, but device weight and size increase significantly
Solution Approach 1:
The patent divides the traditional monolithic shear test machine into separate functional modules: a stationary frame, a movable plate assembly, and independent force measurement systems. This segmentation allows each component to be optimized independently and reduces overall weight while maintaining testing capability.
Solution Approach 2:
The patent extracts the essential testing function from the bulky laboratory machine by removing unnecessary support structures, heavy metal components, and complex carriage mechanisms. Only the core shear testing capability is retained in a minimized form factor.
2Measurement precision
If existing laboratory direct shear test machines are used, then measurement precision is improved, but device size increases
Solution Approach 1:
The testing apparatus is segmented into compact functional units that can be arranged in a space-efficient configuration, reducing the overall volume required for the test while maintaining measurement precision through carefully designed shear planes and force application points.
3Measurement precision
If existing laboratory direct shear test machines are used, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs inexpensive materials such as acrylic or polycarbonate for the shear box and testing apparatus, replacing expensive metal construction. The focus is on creating a disposable or easily replaceable testing device that maintains adequate precision for field applications without requiring costly manufacturing.
4Measurement precision
If existing laboratory direct shear test machines are used, then measurement precision is improved, but ease of operation deteriorates due to immobility
Solution Approach 1:
The patent transforms the static laboratory machine into a dynamic, portable system that can be easily relocated between test sites. The movable plate assembly and lightweight construction enable the device to be transported and reconfigured for different testing locations, maintaining operational ease while preserving measurement precision.
5Measurement precision
If existing laboratory direct shear test machines are used, then measurement precision is improved, but loss of time increases due to sample transport and waiting
Solution Approach 1:
The patent enables preliminary on-site testing of soil samples directly at the construction site before final laboratory analysis is required. This preliminary action provides immediate feedback on soil conditions, eliminating the time loss associated with transporting samples and waiting for laboratory results, while maintaining adequate precision for initial evaluations.
6Measurement precision
If existing laboratory direct shear test machines are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates complex mechanisms such as carriage wheels, heavy metal frameworks, and intricate force transmission systems from the traditional shear test machine. Only the essential shear testing function remains, significantly reducing device complexity while maintaining measurement precision for field applications.
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 portable device provides reasonably accurate soil testing results, reducing idle time for workers and equipment, enhancing safety and efficiency by allowing multiple soil samples to be tested quickly at the construction site, thereby maintaining the integrity of the job site and preserving equipment.
Implementation Method 1
uses two commercially available dial pocket penetrometers, further used as dynamometers, to apply and measure compression force (perpendicular to the shearing plane) and shear force (parallel to the shearing plane)
Implementation Method 2
Existing devices apply a vertical load, then find maximum corresponding horizontal load which causes failure
Data Source
AI summary
A soil shear testing device having a frame with a first plate and a second plate spaced apart from the first plate and fixed with respect to the first plate for defining a gap therebetween, the first plate having a first plate aperture formed therein and the second plate having a second plate aperture formed therein and being coaxial with the first plate aperture. A movable plate being insertable into the gap, having a movable plate aperture formed therein, the moveable plate being insertable into the gap into a receiving position where the moveable plate aperture is coaxial with the first and second plate apertures for allowing the device to accept a soil sample column, the gap having a depth for permitting the movable plate to be displaced past the receiving position for shearing the soil sample column at two separate shearing planes defined by opposite sides of the moveable plate.