MODEL TESTS STUDY ON RECOVERY TECHNIQUE OF THE LATTICE DEFECTS USING CARBON FIBER CLOTH

The lattice framed anchor structure is one of popular prevention technologies in the slope and landslide engineering. The local damage generally occurs to the lattice beam in long-term service, which would have impact on the long-term stability of slope or landslide. For this purpose, attaching carbon fiber cloth to the lattice beams is the most proven effective measure to repair the defects of lattice beams. This paper simulated the landslide mass by way of filling clay in the tank of indoor model test, designed the lattice beams with a similarity ratio of 1:10, and conducted model experiment of carbon fiber cloth applying to the repairing technology of lattice defects by using the lifting jack to exert the landslide load, so as to monitor the parameters including the soil pressure at the bottom of lattice beam, stress of lattice beam and displacement of lattice beam, and analyzed the load bearing ratio between the lattice beam and the carbon fiber cloth before and after repair by using carbon fiber cloth, improvement of steel stress and laws of previous and present change in the bending moment of lattice beam. It showed through analysis of experimental data that the load bearing ratio between the carbon fiber cloth and the lattice beam was improved. When the landslide load acted on the composite of carbon fiber cloth and lattice beam, the carbon fiber cloth sustained the load ahead of the lattice beam, and the load sustained by the carbon fiber cloth was greater than that sustained the lattice beam, with the load bearing ratio of about 83% for the carbon fiber cloth. The lattice beam was damaged by tension first and then compression. In the model test, the strain gages were stuck in the surface of steel to monitor the strain of steel and that the stress in the steel was improved after the damage was repaired, and the maximum stress in steel after repaired was approximately 1/8 of that before repaired. This paper studied the change in bending moment of lattice beam before and after the lattice beam was repaired, which found that the bending moment of lattice beam was significantly decreased upon repair using the carbon fiber cloth, about 1/10-1/3 of what it was before repairing. In consideration of the research results above, it is remarkably effective for the carbon fiber cloth to be used to repair and reinforce the defective lattice beam engineering.