Behavior of bladder-type inflatable anchors in sand: Physical modeling

Area of Science:

• Geotechnical Engineering
• Foundation Engineering
• Material Science

Background:

• Inflatable anchors are innovative support members for foundation pit engineering.
• Multi-bladder inflatable anchors utilize multiple hydraulically inflated rubber membranes for enhanced pull-out capacity.

Purpose of the Study:

• To investigate the influence of inflation pressure, embedment depth, number of bladders, bladder length, and rubber film thickness on anchor performance.
• To evaluate the pull-out capacity and displacement characteristics of bladder-type inflatable anchors.

Main Methods:

• Experimental testing in a cylindrical steel chamber filled with medium coarse sand.
• Systematic variation of key parameters including inflation pressure and number of bladders.
• Analysis of pull-out behavior and benchmark determination using similarity ratios.

Main Results:

• Multi-bladder anchors demonstrate significantly higher ultimate pull-out capacity compared to single-bladder designs.
• Two-bladder anchors showed 1.2x higher capacity and 37.5% less displacement than single-bladder anchors.
• Three-bladder anchors exhibited 1.7x higher capacity and 32.3% less displacement than single-bladder anchors.
• Inflation pressure and rubber film thickness critically impact bearing capacity; bladder number controls displacement.

Conclusions:

• Multi-bladder inflatable anchors provide superior pull-out capacity and stiffness.
• The number of bladders is an effective parameter for controlling anchor displacement.
• Optimizing inflation pressure and rubber film thickness is crucial for maximizing bearing capacity.