Study On Post-Grouting Of Bored Piles In Passage Bridge Construction Of Changchun-Siping Highway

Bored pile has been widely used in our country`s construction, the sediment in pile tip and the mud cake in pile side have great influence to pile`s bearing capacity. Currently, the method to solve those problems is post grouting. By injecting consolidation grout into pile tip or pile side, sediment and mud cake can be eliminated with the effect of penetration replacement, splitting reinforced and compaction solidification, it also can improve pile-soil contact conditions, thus, the pile`s capacity can be improved.This article analyzed the grouting principle and factors of post grouting with bridge reconstruction in Changchun-Siping highway, summarized the formula of pile-end post grouting, designed its construction technology. Field test on effect of post grouting by self-balance method, the test results indicated that the pile-end post grouting can effectively improve pile`s bearing capacity and decrease pile`s settlement. The post grouting technology can obviously control the settlement.The nature of grout has great influence to the design of post grouting, this article summarized the water-cement ratio and grouting pressure combining with laboratory grout mixing simulation test and numerous projects about post grouting of domestic and foreign.Analyzed the Q-S curve, load-pile top displacement curve, axial force, side friction and side friction-relative displacement curve of piles after post grouting and without post grouting to research the improvement effect about ultimate bearing capacity and displacement of pile-end post grouting technology, combining with the results of self-balance field test.