Study On Technique Of Treatment For Jump At Back Of Abutment In Loess Area By The Flexible Approach Slab

Bridge bump is one of the problems that encountered when freeway are constructed in loess area. On the basis of analyzing and generalizing the jump at back of abutment in loess area, the treatment technique of the Wedged-shape Flexible Approach Slab was put forward in the paper. The treatment technique was systematically studied by test in the mechanical character of the flexible approach slab, indoor model test, numeric analysis and field test.Using the new Geosynthetics-Geocell, the Flexible Approach Slab was put forward. The construction's layer of Geocell was studied in mechanical test, load area, ground strength, loading speed and shear character. The study indicated that lateral restraining, friction, net-sliding action of Wedged-shape Flexible Approach Slab could increase ground strength and decrease ground subsidence.From the jump treatment adapting to ground subsidence, home-made model box and jacking apparatus simulate filled-in ground subsidence at back of abutment, making many work conditions' model test at rate of 1:5. The soil pressure and subsidence in varied depth of soil were monitored, systematically studied the reinforcement effect, action and adaptability.Based on the FEM software-MARC and through assumed conditions of varied ground subsidence and simulating interacting of fill and Wedged-shape Flexible Approach Slab, the numerical simulation to action of using Wedged-shape Flexible Approach Slab treating bridge bump were done. Design parameters of Wedged-shape Flexible Approach Slab were optimized.Putting forward corresponding construction process and quality assurance measure of Wedged-shape Flexible Approach Slab treatment. Carry out large-scale plate-bearing test and flexure test combine with entitative engineer, post-load settlement observation is doing at the same time and the treatment effect of geocell...