## 1 Introduction  
Because the facilities installed during a construction project are usually temporary, when applying an earth retaining method for the ground excavation in an urban setting, a stability analysis is generally conducted using the earth pressure and without considering the stability under a cyclic load or earthquake event. However, even when such a retaining method is applied, there may be special circumstances in which the structure is maintained for longer than the normal two-month period (the standard in the Korea [1]). However, investigations into the stability under cyclic loading or earthquake events have typically been simplified or even omitted. The occurrence of earthquakes has recently increased worldwide with the increased activity of the seismic belt. Consequently, the development of stable earth retaining walls is becoming increasingly important. In addition, unlike static loads, the behavior of the ground differs under dynamic load conditions such as cyclic loading. In recent years, the change of earth pressure or earth pressure coefficient have been studied mainly through laboratory model tests or numerical analysis of the grounds with retaining walls or earth retaining walls [2; 3; 4; 5; 6]. A few studies have been conducted to assess the deformation of structures caused by dynamic loads such as railway loads. Therefore, dynamic behavioral analyses are required for cyclic railway loading. Figure 1 shows a diagram outlining an earth retaining wall used to improve the stability through the installation of stabilizing piles (hereinafter referred to as the \"back support\") at an angle and  
connecting them to the front wall (hereinafter referred to as the \"front support\"). This is called an inclined earth retaining (IER) method. An IER structure increases the stability by preventing the earth pressure from acting on the front wall as a result of the connection between the front and back supports. The stability of an IER structure was confirmed through laboratory model tests and field experiments. First, prior to the laboratory model experiments, an IER model was installed in a plane strain model box placed in ground consisting of sand or clay. The lateral displacement according to the installed back support was then analyzed. The decrease in lateral displacement for the case in which the back support was placed in sandy ground was only 8% compared to the case without a back support [7]. When placed in clay however, the lateral displacement decreased by 68% when the back support was installed [8]. Therefore, the lateral displacement is suppressed from the combination of inclined front and back supports, which is a feature of an IER structure. Based on an analysis of the stability and field applicability, as well as field experiments and laboratory tests of the soil deformation in clay ground, it was confirmed that the spacing between the front and back supports is important [9]. However, such studies did not analyze the dynamic stability required in the field where structures are maintained for a considerably long period, including embankment construction for a double line high-speed railway or rockslide prevention during the installation of a retaining wall (Figure 2). In this study, the displacement restraining effect of the IER method applied to embankment construction was analyzed by considering the ground and analysis conditions used by [PERSON] et al. [10] under dynamic loading. In addition, a two-dimensional (2D) dynamic numerical analysis was conducted. By analyzing the lateral and vertical displacements, the effect of the presence or absence of the back support was compared and the displacement restraining effect was investigated for the same H-pile per length. Figure 1: Basic structure of the IER (inclined earth retaining) method. Restraining Effect of Lateral Displacement of Inclined Earth Retaining (IER) Structure During Field Embankment Experiment  
[PERSON] et al.