BIDIRECTIONAL ADJUSTABLE ANCHOR CABLE BASED ON YIELD DEVICE AND DISC SPRING

The Sichuan-Tibet traffic corridor passes through the frozen soil area of the Qinghai-Tibet Plateau. During its life cycle,the slope protection projects would inevitably and adversely be affected by frozen soil. Some prevention and control projects nearby were damaged during the freeze-thaw cycles. To mitigate the adverse effects,we proposed a new anchor cable. The new anchor cable was mainly composed of the disc spring system and yield device. We made and tested 7 groups of yield sets with different lengths,different contact methods and different outer diameters. And we found some samples that could provide sufficient yield force and stroke. Then we proposed a calculation method for the key parameters of the yield set. We developed a yield device which consists of 4 yield sets. Each yield set could provide resistance force 120~135 kN. The total initial yield strength was 420~450 kN. The yield stroke can reach more than 100 mm. We performed the tension test of the disc spring anchor cable in the laboratory. The laboratory test results showed that the growth of the force was reduced by 60% during the frost heave process. And the loss of the force was reduced by about 40% during the melting process. We analyzed the working principle of disc springs on the basis of experiments. We combined the yielding device and the disc spring to form a new anchor cable and tested it under tension. The laboratory tests showed that it could adjust the prestress in both directions effectively. After the end of the yield stroke,we carried out the ultimate bearing capacity tests of the anchor cables. The ultimate bearing capacity of the anchor cable was 1050 kN. The initial yield force and the stroke of the anchor cable could be extended as needed. The performance of the new anchor cable was better than similar products in the market. It could be used for landslide protection in seasonal frozen soil areas along the Sichuan-Tibet traffic corridor.