A servo controlled gradient loading triaxial model test system for deep-buried cavern.

Area of Science:

• Geotechnical Engineering
• Geomechanics
• Civil Engineering

Background:

• Deep-buried caverns experience complex geostress conditions.
• Accurate simulation of in-situ geostress is crucial for understanding cavern stability.
• Existing model test systems often lack the precision to replicate real-world geostress gradients.

Purpose of the Study:

• To develop and validate a servo-controlled gradient loading model test system.
• To simulate realistic geostress fields around deep-buried caverns.
• To investigate the geomechanical response of underground structures under simulated stress conditions.

Main Methods:

• Development of a gradient loading apparatus with independently controlled zones.
• Implementation of a digital servo control system for automated and visualized loading/unloading.
• Utilization of optical and grating-based methods for precise deformation monitoring.
• Conducting a 3D geomechanical test on a simulated deep-buried underground reservoir.

Main Results:

• The system successfully simulates gradient geostress, enabling realistic cavern geomechanics testing.
• Radial convergence increased rapidly with reservoir stress release.
• Model deformation correlated positively with increased gas production rates, consistent with field observations.

Conclusions:

• The developed servo-controlled gradient loading system is effective for simulating geostress in deep-buried caverns.
• The system provides valuable insights into the geomechanical behavior of underground structures.
• Findings have implications for petroleum engineering and the design of deep-buried facilities.