VELOCITY OF VISCID FLOW LANDSLIDES IN THE EVENT OF A PILE CURTAIN AND A CONTINUOUS RETAINING WALL

In regions of intensive precipitation, slopes tend to become viscid due to accumulated moisture. The ultimate resistance of soils susceptible to landslides is equal to zero, while shear stresses between layers are proportional to the velocity gradient. To prevent landslides, slope soil is stabilized by a continuous retaining wall or a row of sparsely erected piles. The effectiveness of these methods is measured by the diminishing rate of the sliding speed at the landslide-prone slope. Due to the non-linear nature of the viscid flow, the Navier - Stokes equations cannot be applied. To perform a more precise calculation, the entire flow is broken down into segments in respect of which the analysis of the viscid flow can be performed; individual results are consolidated on the basis of a common parameter. The first flow section, located at a substantial distance from the buttresses, can be considered as a steady stream of plane gravitational motion alongside the slope. In the second section, the slide is obstructed by the buttress and the parallel flow pattern is formed. There occurs a split of the flow at the critical point of entry, located on the front surface of a solid wall or a buttress. The third section, which can be compared with the flow of viscid fluid in a canal, is typical for buttresses that have a significant length in the direction of the landslide flow. The papers hows that the common parameter applicable both to solid and dispersed barriers is the controlled volume of the fluid flow at the point of entry to the pre-boundary area. As a result of application of the proposed methodology, equations were obtained that made it possible to calculate the speed of the viscid slide depending on different types of piles. The paper describes the conditions that make the viscid mass climb over the constructed barrier