# Field and Numerical Investigation of Taihu Resort Cut Slope Failure in Suzhou, China
## 2 Project Overview of the Taihu Resort Landslide  
The slope project is located in Taihu Resort along Taihu Lake in western Suzhou, Jiangsu Province, China. The slope area location coordinates are 31\({}^{\circ}\)18\({}^{\prime}\)14.688 N and 120\({}^{\circ}\)35\({}^{\prime}\)43.368 E. The northwest corner of the site is about 1800 m from the main peak of Tan Mountain, with a height of 253 m. The northeast corner of the site is about 2400 m from the main peak of Xuanmu Mountain, with a height of 231 m (Figure 2). According to a field survey, the soil and rock masses in the Taihu area are composed mainly of mixed limestone and quartz sandstone. The slope area belongs to the monsoon ocean climate zone; the annual rainfall is 1076 mm; and the precipitation period is concentrated from 26 February to 10 September. The precipitation in June and July is estimated to account for 48% of the annual rainfall [China Meteorological Data Sharing Service System]. Furthermore, the increase in the lake water level has a big impact on the slope during monsoon rainfall, and there are no springs or valleys that cut the slope or at the foot. In March 2012, the construction of Taihu Resort (Zhu Mountain) began, and the slope was excavated on the east side of the project with a width of 34 m and a length of 55 m according to the design requirements. In all, 1690 m\({}^{2}\) of slope excavation surface area was required. The geology and topographical map of the study area of the Taihu slope are shown in Figure 2 and Figure S1. The slope design of the top elevation is approximately 13.93-15.11 m (Figure 3), and the slope direction is east-west and inclined to the south.  
Figure 1: Location of the Taihu Resort landslide.  
The topography of the southern Taihu slope at the middle part is inclined about 10\({}^{\circ}\)-20\({}^{\circ}\), while the slope foot has a gentler angle of about 5\({}^{\circ}\)-10\({}^{\circ}\), and the project terrain is relatively flat. Photos of the original and the cut slope failure are shown in Figure 3. According to drilling holes and a field geological survey, the stratigraphic structure of the slope body is relatively simple. The strata within the depth range revealed by drilling at the site are divided into four engineering geological strata as follows: The top and second soil slope layers are mainly composed of cohesive soil and silty clay, respectively, with medium dry strength and medium compressibility (gray-yellow, gray-white, plastic). The third layer  
Figure 3: Geological model and modified design scheme of the Taihu Resort slope \(0\).  
Figure 2: Geology and topographical map of the study area of Taihu slope (interpreted from the original data).  
is composed of medium-thick layered argillaceous siltstone intercalated with argillaceous quartz sandstone and silty mudstone (brown-red, gray-yellow, and gray-white), which is mainly composed of cohesive soil and gravel. The base layer of the slope is composed of strongly weathered quartz sandstone (brown-red, gray-yellow, fine-grained structure, and calcareous cementation). The slope location is in a low, mountainous, and hilly area. Figure 3 shows the scheme of the geological model and the revised design (excavation scheme) of the Taihu slope.