Flexible Reinforcement Method and Field Monitoring of Expansive Soil Cutting Slope
To develop a method for reinforcing newly excavated expansive soil slopes and elucidate their working mechanism,a reinforcement structure comprising a flexible facing and soil nails was designed,and the corresponding design methodology was developed.The design calculations and a field test of the reinforcement structure were conducted in conjunction with the slope reinforcement project on a weakly expansive soil cutting slope along a highway in Yunnan Province.The working mechanism of the flexible reinforcement structure for the expansive soil cutting slope was investigated through field monitoring of the stress and deformation of the reinforcement structure.The results indicate that allowing a 3.0％swelling deformation normal to the slope,the normal swelling stress can be reduced by 61.1％compared to the case where no swelling deformation is allowed,and the designed flexible reinforcement structure can meet the stability requirements.Over the one-year monitoring period,there was a general increase in the axial force in the middle of the soil nails during the rainy season and a significant decrease in the axial force at the ends of the soil nails closer to the slope surface during the dry season.The axial force along the length of the soil nails generally showed larger values in the center and smaller values at the two ends.The force was more uniform and sufficient compared to that of the anchor frame beam.The maximum tensile strain of the flexible-facing mesh was observed after the rain stopped,with a significant hysteresis that was much smaller than the ultimate elongation of the material.The change in soil pressure on the slope surface was similar to the change in strain pattern of the high-strength reinforced three-dimensional mesh,with fluctuating growth in the rainy season and gradual decrease in the dry season.The increase in soil pressure on the slope surface was close to the calculated swelling pressure.As the soil swelled in the rainy season and contracted in the dry season,the axial force of the steel cable rope showed slow growth,continuous decay,and stabilization phases.The horizontal displacement of the slope crest is the largest among the three monitoring points,at 5.4 mm,indicating that the slope was stable.The monitoring results comprehensively reflect how swelling was controlled by the mechanism of the flexible reinforcement structure.This study provides a reference for the reinforcement design and construction of newly excavated expansive soil slopes.
NETL
NSTL
万方数据
