| In high mountain area, the foundation of bridge is a complex and important part in thestructure design and it also occupies a very big part in entire cost of bridge. The terrain andgeology of mountainous area highway is complicated, the ground surface elevation changesgreatly and there are many poor geological phenomenon such as karst, collapses, unstable slopeand the cliff. Therefore, the even, vertical, the horizontal should be all restrained when buildingthe route. Correspondingly, there are many curved slope bridges, many high pier and big cross,many pier forms in mountainous area highway bridge. Then the relationship between bridgestructure and geology should be considered fully. Generally speaking, the bridge foundation inslope area needs sustain of sufficient horizontal load, vertical load and has good aseismicperformance because it has the high pier, long span and relatively sever seismic intensity.Therefore, in order to improve the horizontal bearing capacity and reduce constructioninvestment, this study of new foundation not only has great economic effect, but also has greatsignificance of social effect and environment protection.Based on the G405 national highway rebuild projection and the technique of anchor tensionpile, the anchored pile foundation was adopted. This anchored pile foundation can improvedhorizontal bearing capacity on tergopleural side, which can make the abutment meet the forcerequirements, can reduce projection investment and construction risk.As it's the first time for using of anchorage foundation in the bridge foundation (there aremerely reports about the preload anchors using in redressing deviated piers of slip area andresisting bridge foundation slipping) and the control of bridge pile foundation deformation is veryimportant in the mountain area. In this paper, based on the concrete engineering geologycondition, the 3-D (three-dimensional) finite element numerical simulation was used to simulatethe reinforcement mechanism of anchors, which can check the feasibility of this project.According to the simulation and research of reinforcement program, we can get the simulationresult of horizontal displacement and settlement. By comparing this new pile foundation withgeneral pile foundation, the advantages and disadvantages of this new pile foundation in controlof deformation, cost, excavation and other aspects were discussed in this paper..Bases on the numerical value simulation and economy contrast, the following conclusions could be obtained:1. Majority of the bridge foundation in G405 line rebuilds the project is built on precipitousslope with badly rockmass. Bases on the survey and analyses of bridge foundation in the world,the anchor (rope) reinforcement in bridge foundation is to be proposed for the first time.2. In order to study its stress characteristic, reinforcing effect and true objective, the 3-Danalyze model of pier, abutment and pile was built by 3-D finite element method analysis.According to the simulation results, the stress in anchor reinforcement pile foundation of pier like40m and 100m level is more reasonable than general pier foundation because it can restrict thelevel displacement of foundation effectively.In order to confirm the stress characteristics and the reinforcement effect of reinforcedbridge new foundations, the three dimensional analysis model of pier, cushion cap and pile wasset at the first time and the d finite element software was used to do the analysis. Thecomputation results has shown that the anchoring pile foundation is more reasonable than thecommon pile foundation and can limit the horizontal displacement of foundation effectively.3. Even take the repair cost into account, this new type anchor (rope) reinforcement pilefoundation has bigger economic effect than manually excavated piles. Considering this newrockbolt (rope) reinforcement pile foundation can cut down the foundation and the excavation ofslope, which is beneficial to protect the environment and receive social benefits andenvironmental benefits.
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