Application And Calculation Of Geosythetics In Widening Of Old Road

In recent years, with the rapid development of economic construction in our country, high-grade highway construction is evolving with unexampled speed. Also the traffic volume of the constructed high-grade highways in 1990s in our country has been saturated at first, and these highways need widening and improving. What's more, many 2 or 3 grade highways in the highway network of country also need to be rebuilt, and this also deal with widening and heightening of the embankment. In the process of widening and improving the used road, how to assure the new & old embankment, especially on soft ground, not occurring significantly different settlement and minimizing the deformation and crack of the pavement is a problem to be solved simultaneously. The most economic and feasible approach to solve the question is to select a correct embankment structure, to improve the whole and lateral stability between the new & old embankment.Geosynthetics(such as geotextile, geogrid and so on) can be used as a treamment in the process of widening the used road on soft ground. On the one hand, the tensile strength of geosynthetics can reinforce the structural association between the new & old embankment, and make them have enough entirety. On the other hand, geosynthetics can reduce settlement of the subgrad, and greatly reduce non-uniform settlement of the new & old embankment.In this paper, according to the reaction of deformation and crack of pavement caused by the non-uniform settlement and the whole stability between the new & old embankment after widening the used road on soft ground, based on the study of settlement and stability of soft ground, the author systematically analyzed the mechanism of geosynthetics in the widening pavement structure, and presented a whole settlement computing method of reinforced embankment in widening structure with the theory of soil mechanics.What's more, the paper, based on a project example, suggested a rational widening embankment structure. By using finite element software-ANSYS, and according to different environment on soft ground (including different height of embankment, different thickness of soft ground and different layer-number of reinforcements and so on), the paper also analyzed the effects of the geosynthetics which reducing the non-uniform settlement of the new & old embankment, the deformation characteristics and settlement rule of the widening embankment structure, then presented rational widening programs of the embankment structure.