Passive soil pressure on sloping ground and design of retaining structures for slope stabilisation

Abstract

Soil-retaining structures, such as anchored, gravity and diaphragm walls can be used effectively to stabilise unstable, shallow slopes. The present work focuses on assessing the passive soil pressure that can be mobilised by passive and active retaining structures used for slope stabilisation purposes; passive structures are taken to be those left free to move and find their own equilibrium against the soil pressure, and active structures those equipped with pre-stressed ground anchors that lead to an upward movement against the unstable sloping soil. The numerical analyses performed with the Abaqus finite-element code and the comparison drawn with available theoretical solutions show that, in the case of passive retaining structures, the maximum horizontal soil pressure that can be exerted by the unstable soil layer on the retaining structure is independent of soil–wall friction and coincides with Rankine's passive value. However, in the case of active retaining structures, the passive soil pressure may be much greater than Rankine's value and should be evaluated as suggested by Eurocode 7 (geotechnical design). Such a high soil pressure is only meaningful for the purpose of sizing the retaining structure, however, because (just uphill from the stress region perturbed by the soil–wall friction and ground anchor) the stress state at rupture coincides with Rankine's theory in the case of active retaining structures too. Thus, even in the case of anchored retaining structures, the maximum soil pressure that can be exploited for slope stabilisation coincides with Rankine's value. These conclusions have important consequences for the dimensioning of soil-retaining structures for slope stabilisation purposes. A practical application for slope stabilisation is discussed in the final part of the paper.

New Arm-Stretching-Type Anti-Slide Pile Design and Verification

“…These measures mainly include retaining walls and anti-slide piles (Li et al, 2016;Li et al, 2019;Chen et al, 2020;Liu et al, 2021). A retaining wall is primarily used for the control of small, shallow landslides (Trandafir et al, 2009;Jiang and Towhata, 2013;Muraro et al, 2015), and its construction process has a significant impact on landslide stability. Furthermore, the cost of constructing retaining walls is significantly higher than that of constructing anti-slide piles.…”

A calculation method for the embedded depth of stabilizing piles in reinforced slopes

“…For the separated full-length piles used to reinforce slopes or landslides, the internal forces of the piles, the ultimate lateral pressure on the piles, the stability of the piled slopes, and the pile spacing involved in the soil arching effect between two adjacent piles have been thoroughly investigated. [23][24][25][26][27][28][29][30] However, from the perspective of the rational thrust force on the pile, if the part of the pile above the slip surface (herein referred to as the loading segment of the pile) is appropriately reduced while the pile position remains unchanged, the thrust force will be reduced simultaneously. Therefore, compared with full-length piles, embedded piles, for which the pile top is buried in the slide mass at some depth, are more cost-effective in many cases.…”

“…31 For a slope reinforced with embedded piles, overtop-sliding failure is a potential occurrence. 26,29,32 To maximize the anti-sliding effect of the embedded stabilizing piles, the determination of the embedded depth of the pile top is significant in practice. Xiong 33 conducted some laboratory model tests for a practical piled slope to reveal the rational embedded depth in engineering.…”

“…Traditional stabilizing piles are usually full‐length structures, which means the pile head is usually at the top surface of the slope. For the separated full‐length piles used to reinforce slopes or landslides, the internal forces of the piles, the ultimate lateral pressure on the piles, the stability of the piled slopes, and the pile spacing involved in the soil arching effect between two adjacent piles have been thoroughly investigated . However, from the perspective of the rational thrust force on the pile, if the part of the pile above the slip surface (herein referred to as the loading segment of the pile) is appropriately reduced while the pile position remains unchanged, the thrust force will be reduced simultaneously.…”

“…For a slope reinforced with embedded piles, overtop‐sliding failure is a potential occurrence . To maximize the anti‐sliding effect of the embedded stabilizing piles, the determination of the embedded depth of the pile top is significant in practice.…”