Experimental Study On Resilience Modulus In Controlling Bumping At Bridge-head Using Two-way Tensioned Geogrid

Vehicle bumping at bridge-head is a common quality fault of theexpressways in our country. Though much work has been done about this at home and abroad, good method hasn't been found yet. With the development of expressway construction in our country, it is urgent to solve this problem theoretically and practically.First, the existing achievements on this problem are summarized in the thesis, combined with the construction reality of our country the reasons lead to the bumping phenomenon are analyzed here and the tolerance settlement value of the embankment at bridge-head that regulated by the current criterion is discussed also. After analyzing the simplified vehicle bumping models built in this thesis, the conclusion that the auto load on the connecting part between the abutment is larger than that of embankment can be drawn.The author use the two-way tensioned geogrid to reinforce silt soil which comes from intense weathering red gritstone, finish the modulus of resilience experiment on samples of different degree of compaction and reinforcemental number of layers (degree of compaction:90%,95%,100%; number of layers: 0,1,2,3,5),Summarize and analyze the influence rule of the two-way tensioned geogrid location , numbers of layers and the degree of compaction on modulus of resilience. And use the red gritstone silt soil build an embankment which reinforced by two-way tensioned geogrid. It divided to four sections, three have been reinforced ,the space between each layer are 20cm, 40cm, 60cm ,the last section without reinforcement. Through mensurate modulus of resilience on the four sections, we find modulus of resilience on the embankment reinforced by two-way tensioned geogrid increase with the minish of the space between the layers ,but the increment rate is down.Outcome of the test show us the appropriate of reinforcemental way , the number of layers and degree of compaction can increase the modulus of resilience on embankment, which show that the technique of the two-way tensioned geogrid make the back of abutment and bridge-head embankment easy transition come true, and make progress on control the Vehicle bumping at bridge-head.