Suction Influence on Load-Settlement Curves Predicted by DMT in a Collapsible Sandy Soil

Area of Science:

• Geotechnical Engineering
• Soil Mechanics
• Foundation Engineering

Background:

• Plate load tests (PLT) are reliable for assessing footing behavior on unsaturated collapsible soils.
• Soil suction significantly influences load-settlement behavior, but inundation for PLTs is costly and time-consuming.
• Scale effects and varying suction profiles complicate in situ testing on collapsible soils.

Purpose of the Study:

• To present a novel device for flat dilatometer (DMT) testing that allows local soil inundation.
• To obtain the DMT-constrained modulus (M) for both natural and inundated soil conditions.
• To develop a model predicting load-settlement curves using DMT data, accounting for suction effects.

Main Methods:

• A device was developed and attached to a DMT blade for in situ local soil inundation.
• DMT-constrained modulus (M) was measured in natural and inundated collapsible soil conditions.
• A predictive model was created using DMT data to estimate load-settlement curves.

Main Results:

• The DMT-constrained modulus (M) showed an average reduction of 56% from natural to inundated conditions.
• The predictive model accurately estimated load-settlement curves based on DMT data.
• Predicted curves demonstrated good agreement with curves obtained from traditional Plate Load Tests (PLT).

Conclusions:

• The proposed DMT-based procedure offers an efficient method to evaluate load-settlement behavior under varying suction.
• This technique facilitates the prediction of shallow foundation performance, considering suction and collapse phenomena.
• The device enhances practical engineering applications by simplifying the assessment of collapsible soils.