# Field and Numerical Investigation of Taihu Resort Cut Slope Failure in Suzhou, China
## 1 Introduction  
Landslides triggered by human excavation or rainfall are among the most common geological disasters and are the core issue of slope engineering research around the world. During the period 2004-2016, the total cases of landslide events show that there were 4862 landslides around the world [1; 2; 3], of which 409 occurred only during the monsoon rainfall. In China, from 1994 to 2018, 126 landslides were recorded after construction under rainfall, which represents 74.1% of all failure cases, and 22.4% of failures after 8 days of heavy rainfall intensity [4]. These landslide disasters caused great loss of life and property. Many research investigations have discovered that failure on slopes is mainly caused by excavations [5; 6; 7; 8; 9], rainfall infiltration [10; 11; 12; 13], or by human excavations accompanied by rainfall [14; 15; 16]. To avoid costly losses from sudden landslides, it is of great significance to conduct a comprehensive stability analysis of slopes under different scenarios. Methods such as finite elements have become a widely applied research topic in the field of geotechnical engineering for the estimation of slope stability. Further, the safety factor is considered the key indicator of slope stability. Over the previous decades, the strength reduction technique in finite element slope stability analysis has been employed by many authors, due to its efficiency in estimating slope stability [17; 18; 19; 20; 21; 22; 23; 24; 25]. At present, the technique has been developed to analyze the stability of complex geometries such as excavation slope models [26; 27; 28; 29; 30]. This method provides unique safety factor results by using the Mohr-Coulomb (MC) failure criterion [31; 32]. Recently, the authors have examined the influence of rainfall intensities on slope safety factors [33; 34; 35; 36]. Many factors lead to slope instability. In excavation slope engineering, the failure of cut slopes may be related to factors such as inadequate drainage, erosion control measures, slope angle, irregular monitoring of the cut slope, and geological setting, which is an important component of the cut slope's stability. A lack of geological investigation prior to design may increase the possibility of failure on the cut slope [37]. Many scholars have investigated excavation-induced landslide cases in China [38; 39]. They found that the failure was caused by the excavation of the slope toe with an inadequate slope geological investigation. [PERSON] et al. (2022) [40] found that the excavation of the slope in Sichuan Province was performed without a proper understanding of the geological condition of the slope. [PERSON]. [PERSON] et al. (2013) [41] analyzed a case study of a slope failure induced by excavation near Xliudou Dam. According to the results, the damage was primarily caused by excavation that activated the ancient slip zone, thereby allowing external factors to impact the slope and cause a shallow slide. Therefore, as a precaution against future failures of cut slopes, it is usually necessary to study the cut slope failure after a landslide, obtain an adequate interpretation of the causes of collapses, and conduct a series of comprehensive landslide examinations [42; 43; 44; 45]. As a result, the above-mentioned authors adopted different approaches and instruments to monitor landslide conditions. These studies provide a substantial contribution to the investigation of the complex structure of landslide areas. Hence, such investigations provide ideal guidance for land-slide emergencies. The recent research on the landslide mechanism caused by human excavations has been advanced by introducing different work conditions to reveal the instability mechanism after and before excavation, which provides an early warning measure for slopes exposed to cutting. For example, [PERSON] et al. (2021) [47] and [PERSON], [PERSON] et al. (2022) [48] analyzed a different landslide case in China.