Research On Compensation Techniques Of Anchorage Prestress Losses

The prestressed anchorage has been widely used for geotechnical engineering. In order to ensure the efficiency of active reinforcement, the stress of anchorage should be steady and lasting during service period. But the creep of reinforced rock may lead to a large amount of prestress losses and failure of reinforcement. In this case, accidents would happen. Therefore, it’s necessary to study the mechanism of stress losses and search for techniques which can reduce the stress losses of anchorage, the same as compensation techniques of prestress losses.This paper has research on compensation techniques of prestress losses by the method of comprehensive investigation and analysis, the main contents and conclusions were as follows:(1)Having investigated the reinforcement datas, this paper summed up the unefficient reasons and patterns. Inspect methods of anchorage stress and mechanism of stress losses were introduced and analyzed.(2)Factors and evaluation index of research were selected seriously, orthogonal experiment design method was used for the design of experiment schedule. Numerical model for analysis was created by software ABAQUS. Anchorage was simulated by the function of bolt in ABAQUS.(3)Results of prestress research and compensation technique research were calculated by finite element analysis, and they were discussed by the method of orthogonal design-direct analysis. The mechanism of stress losses was summarized. It shows that creep usually occurs among the rocks which under the anchor block and near the tips of anchorage grout. If stress concentration in these areas could be eliminated, the stress losses will be decreased.(4)Compensation techniques of prestress losses were summarized at last. Compensating tensioning was recommended for comensation of prestress losses, prestressing force and size of anchor block should be added. If necessary, depth and diameter of anchorage hole should be increased, and compression dispersion anchorage or compression concentrated anchorage could be used, because their stress condition in anchorage zone were better.