The Tianjiaba landslide on the Hang Rui expressway was located in the south of Sinan County, Tongren City, Guizhou Province. From the night of 2 July to the morning of 3 July 2011, numerous house cracks, foundation subsidence, and surface cracks suddenly occurred in the Tudiwan and Tianjiaba villages on the north and south sides of the management area. Based on the field geological survey, drilling, pit exploration, surface displacement, fracture observation, and deep displacement monitoring data analysis the deformation characteristics and causes of the Tianjiaba landslide were comprehensively analyzed. In this study, the landslide was divided into three areas, in which fracture group 3 was the most severe. Among the ten inclinometer holes, the sliding surface displacement of No.8 inclinometer hole was the largest, i.e., 25 mm. The sliding surface slopes of fracture groups 1, 2, and 3 were small, i.e., 12.25°, 4.97° and 6.62° to 4.64°, respectively. The results showed that the displacement values of different positions of the landslide were different, and the ground displacement value was larger than the sliding surface displacement value. The maximum displacement of the ground was 242.68 mm, which is larger than the maximum displacement of the inclinometer hole. Because the displacement of the upper part was greater than that of the lower part, bulging cracks formed in the lower part of the landslide. When the displacement of the upper part was less than that of the lower part, tension cracks formed in the lower part of the landslide. According to the surface cracks and displacement values of inclinometer holes on the sliding surface, the landslide was in the initial sliding stage and filling the platform of the management area on the hillside was the main cause of the landslide.
