Unstable evolution of railways slope under the rainfall-vibration joint action

Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains. However, as two major factors affecting the stability of railway slopes, few scholars have explored the unstable evolution of railway slopes under the joint action of rainfall-vibration. Based on the model test of sandy soil slope, the unstable evolution process of slope under train vibration, rainfall, and rainfall-vibration joint action conditions is simulated in this paper. By comparing and analyzing the variation trends of soil pressure and water content of slope under these conditions, the change laws of soil pressure and water content under the influence of rainfall-vibration joint action are explored. The main control factors affecting the stability of slope structure under the joint action conditions are further defined. Combined with the slope failure phenomena under these three conditions, the causes of slope instability resulting from each leading factor are clarified. Finally, according to the above conclusions, the unstable evolution of the slope under the rainfall-vibration joint action is determined. The test results show that the unstable evolution process of sandy soil slope, under the rainfall-vibration joint action, can be divided into: rainfall erosion cracking, vibration promotion penetrating, and slope instability sliding three stages. If it is in a short period of time when the vibration starts or ends, the slope will also generate structural changes in vibration densification (vibration loosening). In the process of slope unstable evolution, rainfall and vibration play the roles of inducing and promoting slide respectively. In addition, the deep cracks, which are the premise for the formation of the sliding surface, and the violent irregular fluctuation of soil pressure, which reflects the near penetration of the sliding surface, constitute the instability characteristics of the railway slope together. This paper reveals the unstable evolution of sandy soil slopes under the joint action of rainfall-vibration, hoping to provide the theoretical basis for the early warning and prevention technology of railway slopes.