**Sensibility Analysis of the Hydraulic Conductivity Anisotropy on Seepage and Stability of Sandy and Clayey Slope**

#### **Shuyang Yu 1, Xuhua Ren 1,2,\*, Jixun Zhang 1, Haijun Wang 3 and Zhitao Zhang 3**


Received: 1 December 2019; Accepted: 16 January 2020; Published: 18 January 2020

**Abstract:** Evaluation of slope stability under rainfall is an important topic of Geotechnical Engineering. In order to study the influence of anisotropy ratio (*kr* = *kx*/*ky*) and anisotropy direction (α) on the seepage and stability of a slope, the SEEP/W and SLOPE/W modules in Geo-studio were utilized to carry out the numerical analysis of a homogeneous slope in Luogang District, Guangzhou City, China, which is based on the theory of unsaturated seepage and stability. Two kinds of soils (clay and sand) were included. Results show that: For sandy soil slope, the increase of *kr* promotes the rainfall infiltration, and the decrease of α prevents the rainfall infiltration. The maximum water content of the surface (MWCS) reaches maximum with the increase of *kr* and α. The rising height of groundwater (RHG) is −3–4 m and the safety factor (SF) is 1.3–1.7. For clayey soil slope, variations of *kr* and α have little impact on the seepage characteristics and slope stability. The MWCS remains almost the same. The rainfall infiltration depth (RID) is 0.5–1 m and the SF is about 1.7. Therefore, for sandy soil slope, it is not only necessary to consider the influence of *kr*, but also the influence of α. For clayey soil slope, it can be treated as isotropic material to simplify calculation.

**Keywords:** hydraulic conductivity anisotropy; sandy soil slope; clayey soil slope; seepage characteristics; slope stability; numerical simulation
