Deep sliding instability mechanism and remediation measures: The subgrade soil slope along the Jingguang Railway at K1219

Abstract

To explore the deep sliding instability mechanism of a soil slope, taking the subgrade slope instability at K1219+000 of the downward line of the Beijing-Guangzhou railway as an example, the deformation and failure characteristics, geomechanical process and instability causes of the soil slope are detailedly studied. The results show that the width and depth of cracks on the surface of the subgrade slope gradually become shallow and narrow from the top of the slope to the toe of the slope, and the deformation has a certain rotation, with obvious traction characteristics, which belongs to deep sliding and splitting instability. The soil slope has experienced three geomechanical processes: the redistribution of the stress field and seepage field caused by slope toe excavation and pumping, the increasing sliding force caused by rainwater infiltration softening and the deepening of the sliding surface, and the failure of retaining structure resistance. The mechanism of slope instability includes the stage of shallow sliding, the stage of shallow sliding surface moving to the deep layer, and the stage of deep sliding instability triggered by the dynamic load.On this basis, the position of the sliding surface is comprehensively determined and the mechanical parameters of the slip surface are determined by the inversion method. The regulation scheme of rigid frame double row anti-slide piles is adopted. Through theoretical calculation and numerical analysis, the deformation of slope and anti-slide piles are consistent with the deformation monitoring results, which indicates that the theoretical analysis of deep instability of soil slope is accurate and the calculation of mechanical parameters is scientific, and the measures are proven stable and reliable.

Keywords

• subgrade
• soil slope
• deep sliding
• instability mechanism
• treatment remediation measure
• jingguang railway