Abstract: It is of great significant to study the bearing behavior and the design procedure of geosynthetics beneath highway embankment built in karst terrain as a treatment to sinkhole. Firstly, the load and load transfer in geosynthetics are investigated according to its characteristics; and the Terzaghi’s soil arch theory in ideal soil is introduced to evaluate the upper load. The strain in geosynthetics and anchorage length are considered as two key design values, which are related to pull-out length at tip of anchorage segment. Then, the linear elastic-fully plastic model is introduced; and the corresponding analytical solution is deduced by the basic equation. The calculating procedures of the lengths of pull-out and load transfer are established by combining the boundary conditions. Based on these, an example in engineering practice is analyzed with its parameters; and the result calculated by proposed method is compared to that calculated by the method based on fully plastic model. The errors influenced by the width of the hole, the stiffness of the geosynthetics, the height of the upper soil, the friction angle on the interface of the soil and the geosynthetics are studied; and the relationship between the length of load transfer and the height of upper soil is investigated as well. The results indicate that, both the length of pull-out and that of load transfer calculated by the method based on the fully plastic model are larger than that by the proposed method; and the error of the length of load transfer is over 40% in some cases. The design base on the fully plastic model may cause unsafe of engineering.

Key words: road embankment, sinkhole, geosynthetics, linear elastic-fully plastic model, length of load transfer