Hydrated Soil Interface Shear Testing Under In-Situ Pressure and Temperature
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Solution Overview
Problem
Existing testing devices for interface mechanical parameters of natural gas hydrated soil fail to accurately simulate in-situ conditions, including pressure, temperature, and overlying soil pressure, leading to inaccuracies in measuring mechanical properties under large deformations and uneven stress distribution.
Innovation Solution
A testing device and method that includes a reaction kettle with a rotating power mechanism, pressure mechanism, atmosphere regulating mechanism, and temperature regulating mechanism, along with a sample loading mechanism, to simulate in-situ conditions and maintain accurate pressure and temperature control during ring shear tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional testing devices are used for interface mechanical parameters of natural gas hydrated soil, then the testing process is simple, but the measurement precision is poor due to inability to simulate in-situ conditions accurately
Solution Approach 1:
The testing device employs a nested structure where the reaction kettle is placed inside the constant temperature box, and the sample loading mechanism with shear boxes is positioned within the reaction kettle. This nested arrangement allows multiple functional systems (pressure control, temperature control, atmosphere regulation) to be integrated in a compact configuration, enabling accurate simulation of in-situ conditions while maintaining reasonable device complexity
Solution Approach 2:
The testing device integrates multiple functions into a single system: the reaction kettle provides both pressure control and atmosphere regulation, the constant temperature box maintains temperature control, and the sample loading mechanism performs both sample installation and shear testing. This multi-functional design improves measurement precision without proportionally increasing device complexity
2Reliability
If high pressure and low temperature conditions are simulated to match in-situ environments, then the reliability of testing results improves, but the device complexity increases due to additional pressure and temperature control systems
Solution Approach 1:
The reaction kettle combines pressure control and atmosphere regulation functions into a single chamber, while the constant temperature box integrates temperature control with the pressure system. This merging of functions allows the device to simulate high pressure and low temperature conditions simultaneously, improving reliability of results without excessive increase in complexity
Solution Approach 2:
The reaction kettle acts as an intermediary chamber between the constant temperature box and the sample loading mechanism. It transmits and maintains the controlled temperature and pressure conditions to the sample, enabling reliable simulation of in-situ environments while decoupling the complexity of different control systems
3Reliability
If ring shear tests are performed to study large deformation behavior, then the reliability of understanding mechanical issues improves, but the measurement precision deteriorates due to uneven stress distribution at the contact surface
Solution Approach 1:
The interface between the upper and lower shear boxes is designed with specific local characteristics including a rough contact surface and a circumferential groove. The rough interface simulates actual soil-structure contact conditions, while the groove prevents soil adhesion to the box walls. These local quality features enable reliable study of large deformation behavior while minimizing measurement errors from uneven stress distribution
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 device enables precise measurement of interface mechanical parameters under high pressure and low temperature conditions, simulating real-world environments and reducing errors through automated data collection and simulation of large deformations.
Implementation Method 1
The rotating power mechanism outputs rotating power through the output axis to the sample loading mechanism, causing the sample loading mechanism to rotate
Implementation Method 2
The pressure mechanism provides testing pressure to the test sample through the sample loading mechanism
Implementation Method 3
The temperature regulating mechanism regulates the temperature in the first holding chamber
Implementation Method 4
The atmosphere regulating mechanism regulates the atmosphere composition and gas pressure in the first holding chamber
Implementation Method 5
Natural gas hydrates are cage like compounds formed by natural gas molecules such as methane (CH4) and water molecules under high pressure and low temperature conditions
Data Source
AI summary
The present invention provides a testing device and method for determining interface mechanical parameters of natural gas hydrated soil. The testing device includes a reaction kettle, a rotating power mechanism, a sample loading mechanism, a pressure mechanism, an atmosphere regulating mechanism, and a temperature regulating mechanism. The testing method is implemented based on this device. The device and method can improve accuracy and reliability of determining mechanical parameters at an interface of hydrated soil containing natural gas.