# Analysis of Failure Mode of Reinforced Embarments Overlying Voids Based on Discrete Method
## 1 Introduction  
With the gradual laying of the traffic road network in recent years, the environment of road construction has become more and more complex. Some voids are difficult to detect during the survey process and are gradually enlarged by the self-weight of the embankment or the traffic load during road operation, thus causing road collapse accidents [1; 2; 3; 4]. Currently, the horizontal reinforcement method is widely used in engineering to prevent the sudden settlement and instability of embankments caused by overlying voids [5; 6]. Based on the demand of engineering applications, many experts have performed a lot of research in the field of horizontal reinforcement method to prevent voids. The reasonableness of geosynthetic materials to prevent voids was verified via tests [7; 8]. [PERSON] [9] analyzed the deformation characteristics of reinforced bodies. The results demonstrated that a geosynthetic material deflection curve did not completely fit a circular nor a parabolic shape. [PERSON] [10] revealed that the friction angle and particle size within the soil had obvious influence on the deformation and tension of the reinforcement material with the help of a trapdoor test model. [PERSON] [11] analyzed the stress-strain characteristics of the reinforced body and found that the peak tensile strain in the bottom layer of the geogrid was at the edge of the void. [PERSON] [12] analyzed the effect of void span on soil displacement and reinforced body deformation during traffic loading. [PERSON] [13] analyzed the load transfer mechanism and the slip surface shape of the upper part of the void. [PERSON] [14] used PLAXIS to study the effect of reinforcement length and stiffness on the settlement of reinforced embankments overlying voids. By means of finite element combined with discrete element methods, the mechanism of force transfer between the soil and reinforcement was investigated and revealed from a microscopic viewpoint [15; 16]. [PERSON] [17] compared and analyzed the deformation of the reinforced body under three types of load distribution, and concluded that it was economical and reasonable to use the inverted triangular distribution. [PERSON] [18] considered the vertical deformation of the soil in the anchorage area and proposed a method for calculating the deformation of the reinforced body. [PERSON] [19] considered the effect of soil cohesion in the design of the calculation method. A more systematic study of reinforced embankments where the void has collapsed below the reinforced body has been presented in the above literature. In practical engineering, a portion of soil may exist between the void and the reinforcement material in the embankment. For such conditions, [PERSON] [20] investigated the relationship between void depth and embankment bearing capacity. [PERSON] [21] studied the effect of eccentric load and load eccentricity on the bearing capacity characteristics of the void embankment. [PERSON] [22] took a square void embankment as the object of study to investigate the effect of the property of the fill and the relative position of the void on the failure mechanism of the embankment. [PERSON] [23] proposed a failure model for a reinforced embankment overlying a void with a full load on the embankment surface. For rigid pavements, this treatment is feasible. In the case of flexible pavements, the vehicle traffic load is equivalent to a local overload acting on the embankment under road operational conditions. The effects of void depth, reinforced body stiffness and reinforced body burial depth on the bearing capacity of embankments under strip loading have been studied [24; 25], but the failure mode of reinforced embankments overlying voids under local overload has not yet been investigated. The discrete element simulation technique based on the mechanics of particles can consider the discrete characteristics of soil particles, which can effectively reveal the failure mode and microscopic mechanism of soil structure [26; 27].