Application Research Of Foamed Mixture Lightweight Soil In Transition Section Of Road And Bridge

With the rapid development of traffic construction in various parts of China,the number of structures such as bridges and culverts is increasing during the construction of roads and bridges.Engineering problems of differential settlement are prone to occur in the backfill sections of the abutments and backs.During the construction process,the differential settlement of the road-bridge transition section is caused by factors such as differences in structural form,tight construction period,and insufficient compaction of the filling material during backfill construction.Based on the Sanhuan Road Crossing Fufei Road Elevated Project,taking foamed mixture lightweight soil as the research object,through theoretical analysis and numerical simulation calculation as the research method.The engineering characteristics and engineering application of foamed mixture lightweight soil were analyzed and the design,preparation process and construction process of foamed mixture lightweight soil in the transition section of road and bridge were studied.The main research results of this paper are as follows:(1)Combined with the design theory of foamed mixture lightweight soil embankment,the design of the transition section of road and bridge is summarized,including structural design,performance design,etc.(2)For the cross section of the road-bridge transition section,as the filling height increases,the cumulative vertical settlement of the subgrade increases evenly and slowly.Compared with the settlement value at the shoulder,the settlement value at the center of the road is the largest,and the distance from the outer side of the road shoulder Increase,the rate of vertical settlement of the subgrade decreases rapidly.(3)For the longitudinal section of the transition section of the road and bridge,the cumulative vertical settlement of the subgrade increases linearly within 10m from the back of the platform.At 10～20m from the back of the platform,the vertical settlement of the subgrade will grow slowly until it is gentle.(4)Through the differential settlement analysis of the weight-weight grade and elastic modulus of light-weight soil mixed with different bubbles,it is concluded that the bulk density is the main factor affecting the vertical settlement of the roadbed.It is also proposed that the optimal bulk density is W6 and the optimal elastic modulus is 100 MPa.(5)The settlement analysis of elastic modulus,cohesion,internal friction angle and Poisson’s ratio of soft soil layer shows that the change of elastic modulus has the greatest influence on the settlement of soft soil foundation.(6)Compared with the ordinary fill embankment,the maximum vertical settlement of the subgrade of foamed mixture lightweight soil embankment only accounts for 24%of the ordinary fill embankment.(7)Combined with the actual project on site,the advantages of on-site construction of foamed mixture lightweight soil,the advantages of saving time and applicability in engineering application are summarized.