## 1 Introduction  
It is widely recognized that the dynamic response of rock slopes is one of the key issues in geotechnical engineering and earthquake engineering, and there is indisputable evidence of its significance even from the late 1960s [1; 2]. On the other hand, a rock mass usually consists of multiple joints, known as joint sets, which govern the mechanical behavior of the rock mass [3]. The stability of rock slopes is often significantly influenced by the structural geology of the rock, especially discontinuities such as bedding planes, joints and faults [4]. Studies [5; 6; 7] have confirmed that the rock mass structure plays a leading role in the stability of rock slopes under dynamic loads. Therefore, research on wave propagation regularity in a layered-structure rock slope is important for assessing the stability and damage of rock slopes under dynamic loads. Hence, many researchers have studied the dynamic response of rock slopes under stress and tried to simulate the complexity using analytical, numerical, model, and in situ test methods, and valuable conclusions about topography effects and dynamic response regularities have been drawn [8; 9; 10; 11; 12]. However, analytical solutions encounter serious limitations when the geometry is complicated and a great number of influencing parameters are to be incorporated [13]. The results obtained by model test and in situ test methods are limited and cannot be generalized. Due to complicated topography and slope structure, results from in situ test are difficult to obtain. Furthermore, the conclusion from model tests cannot reflect the natural slope. Meanwhile, numerical simulation is an economical and convenient alternative. Few works have been conducted to systemically study plane wave transmission through a layered-structure rock slope. As a result, numerical simulation of the dynamic response of a horizontal layered-structure rock slope is useful. When a wave propagates through fractured rock masses, its attenuation and slowness are mainly induced by rock joints [14; 15]. Analytical solutions and experimental data have proven that the incidence angle of waves, normalized fracture stiffness, number of fractures, and dimensionless fracture spacing have obvious effects on wave attenuation across parallel fractures [16; 17]. Many characteristic parameters of slope and incident waves have effects on wave attenuation through a horizontal layered-structure rock slope, such as height, slope angle, acceleration amplitude, frequency, and so on. Several papers [18; 19] have studied the effects of dynamic actions on the shear strength of rock mass discontinuities. In order to focus on studies of the parameters in which we are most interested, a homogeneous and elastic rock slope with normally incident Sv wave applied under the bottom of the slope is modeled, making full use of the Fast Lagrangian Analysis of Continua (FLAC) method (with the code of FLAC3D V5.0 issued by ITASCA Consulting Group, Inc., Minneapolis, MN, USA). FLAC is a three-dimensional explicit finite-difference program for engineering mechanics computation. This method follows the continuum hypothesis, which adopts the difference format. With continual change of the configuration, the coordinates update according to the solution of the time step integral. Based on the dynamic equation and dynamic method, it is able to simulate the dynamic problem well. One advantage of FLAC is that the FISH language is embedded; therefore, it is convenient to define the constitutive relation and to arrange the monitoring points. Before the simulation of the dynamic response of the slope, the verification of FLAC modeling on wave transmission across rock joints is executed. Through comparison with analytical solutions and FLAC results, the effects of joint mechanical and spatial properties on wave transmission in FLAC modeling are validated.