Formation mechanism and stability analysis of the DR landslide in national road 534 of Datian, Sanming, Fujian Province, China

Abstract

Rainfall-induced landslides occur frequently along roads in Fujian Province, China. Previously, landslides located at roads in Jianou and Yanping in Fujian were reported to claim 23 and 24 lives, respectively. The DR landslide (located on National Road 534 of DR village, Datian County, Sanming City, Fujian Province), with a state of instability and the potential of burying the road and buildings and causing human casualties, is representative. Therefore, there is a need to analyze the stability of the DR landslide. Through detailed reconnaissance and modelling, this study investigated the characteristics, formation mechanism and stability of the DR landslide. Based on GeoStudio software, the stabilities of the upper, middle and lower parts of the landslide were explored in natural, rainfall, earthquake and coupled rainfall-earthquake conditions, with the finite element, Bishop’s simplified methods and others. The results demonstrate that under the above four conditions, the upper and middle parts were stable with stability coefficients greater than the standard engineering values for China, while the lower part was unstable with stability coefficients of critical slip surfaces of 0.871, 0.798, 0.867 and 0.727, respectively, which are less than the standard values. Compared with the natural condition, rainfall influenced stability less, whereas the earthquake and coupled conditions greatly affected the stability. Based on the analyses, some technical support is provided to implement landslide prevention, mitigation and control measures such as filling cracks with grouting and widening the retaining wall.