Research On Methods To Determinate Value Of The Post-construction Settlement For Approach Embankment

With the national economy development quickly, the expressway construction in our country is increasing fast in recent years. But some common faults in these constructed express is existed, such as the jump at the bridge head is universal and typical. The bumping at the bridge head is chiefly caused by the differential settlement between the fill-back soil bridge approaches and the base of abutment.Among the ways to deal with the bridge head bump, setting the approach slap is the most common way. The purpose of that is to disperse the mutational difference of elevation of the faulted slabs in the joining place of the abutment bank to the bridge slab′s two ends, so as to develop the traffic condition. However, the theories upon the approach slap′s changes of the longitudinal slope,deflection and stress is not mature, So sometimes it is hard to eliminate the bridge head bump completely because of the disjoint, rupture of the approach slap, influencing the regular service of the road.On the basis of three aspects, including the changes of the longitudinal slope,deflection and stress, this paper analyse the methods to determinate value of the post-construction settlement for the fill-back soil of bridge approach. Firstly, a mechanic model of man-chair-vehicle system with 3 degrees of freedom is built to analyze the effects on automobile ride comfort due to the differential settlement between roadway approach embankments and bridge structures. On the base of some field survey results on abundant literature and the calculating results in this paper, the controlling criterion of the post-construction settlements for approach embankment has been put forward; then, analyzing the deflection and stress of bearing disjointed approach slap with the theories including plates and shells,the flexible ground beam, determines the criterion of the settlements. The calculation product will benefit for the settlement controlling during the construction, so as to eliminate the hidden trouble of the bridge head bump.