PullーOut Mechanism of Geogrid in Soil and Its Application to the Design Method of Earth Reinforced Soil Wall

Earth Reinforcement by using geogrid has been widely applied to soil结构such as embankments, slopes, retaining wall and foundations，but the设计方法which evaluates the reinforcing effect properly has not been established.Theobjectives of this research to make clear the mechanism of geogrid—earth—reinforcement underpull - out forces, to develop an evaluation method of the reinforcing effectand to establish the design method of the reinforced soil wall. For the purposesa series of pull out tests of geogrid in soil was conducted under different relative density ofsoil. The mechanism of The pull out resistance of geogrid in soil was clarified by discussing Theinteraction properties between soil and geogrid from the test results. mechanism was modeled and在joint element to take it into finite element method.Main中指定的属性conclusions are summarized as follows:1) Strain distribution on the geogrid in soil is not uniformunder pull - out forces, and the corresponding pull - out resistance is the same property，因此，reinforcing effects depends on the relative displacement between soil and geogrid.2)reinforcing effect was evaluated by finite element analysis which the pull - out mechanism wasintroduced in the shearing property of joint element.3) From the分析结果of the reinforcedsoil wall,这应该是设计papameters were the maximum lateral displacement of the wall，the maximum settlement of the foundationvertical stress in the foundation and maximum tensile force of geogrid.4)一种设计方法geogrid - reinforced - soil - wall，which is based on the charts in terms of the design papameters described above, was proposed。

Earth Reinforcement by using geogrid has been widely applied to soil structures, such as embankments, slopes, retaining wall and foundations, but the design method which evaluates the reinforcing effect properly has not been established.The objectives of this research are to make clear the mechanism of geogridーearthーreinforcement under pullーout forces, to develop an evaluation method of the reinforcing effect, and to establish the design method of the reinforced soil wall. For the purposes, a series of pullーout tests of geogrid in soil was conducted under different relative density of soil. The mechanism of the pullーout resistance of geogrid in soil was clarified by discussing the interaction properties between soil and geogrid from the test results. The mechanism was modeled and formulated as a shearing property in the joint element to take it into finite element method.Main conclusions are summarized as follows :1) Strain distribution on the geogrid in soil is not uniform under pullーout forces, and the corresponding pullーout resistance is the same property, so that the reinforcing effects depends on the relative displacement between soil and geogrid.2) The reinforcing effect was evaluated by finite element analysis which the pullーout mechanism was introduced in the shearing property of joint element.3) From the analysis results of the reinforced soil wall, it was shown that the design papameters were the maximum lateral displacement of the wall, the maximum settlement of the foundation, vertical stress in the foundation and maximum tensile force of geogrid.4) A design method for geogridーreinforcedーsoilーwall, which is based on the charts in terms of the design papameters described above, was proposed.