Stability Analysis Of Slope For Gravity Anchorage Of Suspension Bridge Across Dadu River In Luding County

Gravity anchorage is an important form of suspension bridge foundation structures, bearing the main cable load and playing a vital role in the stability of the suspension bridge.Meanwhile the gravity anchorage is adaptable to the geological conditions, so It is widely used in practice. This thesis relies on the Ya’an to Luding highway suspension bridge project in Sichuan Province and analyses the stability of gravity anchorage slope of coarse layer under different conditions, the main research work and results are as follows:1)Static Stability of Luding Dadu Suspension gravity anchorage in 1,3.5,7,10.5 main cable tension conditions of the times was analysed by three-dimensional numerical simulation using MIDAS-GTScombined withFLACSD. Stability factor of the gravity anchored slope in these four conditions were 2.58,2.20,0.703 and 0.703. The potentialfailure mode is the gravity anchorage slip along the interface.2)In the typical main cable tensile force IP,3.5P,7P,10.5P, the gravity anchor saddles point towards the direction of the horizontal displacement of Dadu were 5.11cm,5.74cm, 60.57cm,1.105m. Among them, the latter has far exceeded the permissible value 18.7cm, in this case the anchor role in the failure.3)The long-term stability of the gravity anchorslope was analysed using three-dimensional numerical simulation method based on Creep test in field. The results showed that the gravity of the Dadu bridge anchored slope stability in five years is good, no slope plastically through the area. Saddles point of maximum horizontal displacement is 14.77cmwithin the allowable range.4)The slope stability undertwo designed seismic waves was analyzed by three-dimensional numerical simulationmethod. In the design of the main cable tensionthe slope safety factor is 1.02 and 1.05. The potentialfailure mode is the gravity anchorage slip along the interface. When the main cable tension is overloaded, the slope in such seismic waves will be instability.5)The ramp stress calculation formula was analysed and derived by using limit equilibrium theory. Relationship between the main cable tension and the overload factor was obtained,which is consistent with the simulation results. Approximation theory analysis shows that in the long term, when the single-cable force is less than 5.72P (without regarding to the backfill is 5.22P, P stands for the designed cable force), the anchorage will not depart from the bottom. The bottom and the slope play a supporting role at the same time.The research of the stability of the gravity anchorage slope in coarse soil stratum in the conditions of the main cable tension, super tension, slope creep, earthquake, provides a guide and referenceto calculate and design the suspension bridge gravity anchorage engineering.