Anti-slide Pile Design Research Articles

Anti-slide pile structure development: New design concept and novel structure

The anti-slide pile is one of the most used measures in landslide control globally. Following its application, various structures have been developed. In this paper, we analyze the anti-slide pile structure development process and extract two development paths. One path is aimed at improving the applicability. The second path starts from an in-depth study of pile–soil interactions. However, these two paths share a single design concept: The anti-slide pile provides direct resistance to maintain landslide stability, that is, the anti-slide pile and the landslide body are thought to be confrontational sides. We here propose developing and utilizing the landslide body in anti-slide pile design. Accordingly, the confrontation relationship between the anti-slide pile and the landslide body can be changed while shifting away from the view that the landslide body is only a hazard. On this basis, we also design a novel structure: An arm-stretching-type anti-slide pile. The simulation verification results show that this novel structure works well in realizing the proposed design concept. Compared with the commonly used wholly buried pile, the safety factor of the landslide controlled by the novel structure is improved by 43.56%. This study promotes the design concept of anti-slide pile developing from the existing slide–resist single mode to the slide–self-stabilize–resist compound mode.

A New Multi-Objective Comprehensive Optimization Model for Homogeneous Slope Reinforced by Anti-Slide Piles: Insights from Numerical Simulation

Abstract Landslides have posed a huge threat to the ecological environment and human society all over the world. As the most conventional reinforcement method, anti-slide piles are widely used in the reinforcement of slopes. Currently, more and more attention has been paid to the low-cost and high-efficiency optimal design of anti-slide piles. However, limitations in the method of the optimization design for slopes reinforced with piles still exist. In this paper, a new multi-objective comprehensive optimization method was proposed for the optimization of the slope reinforced with anti-slide piles. The factor of safety, internal force, and deflection of piles were selected as the optimization indexes, and the optimization index weight was determined by integrating the subjective and objective weights. The influence of pile locations, pile lengths, and pile spacings on the reinforcement effect of a homogeneous slope was analyzed via the numerical simulation. Through the simulation case analysis, the proposed model had achieved good effects on the optimization design of anti-slide piles, which could effectively reduce the engineering costs. The optimization results showed that the best reinforcement effect for the homogeneous slope could be obtained when the anti-slide piles with the critical pile length and small pile spacing were located in the middle of the slope. This provides a new solution for the optimization design of other types of complex slopes and has broad application prospects.

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

Anti-slide piles play an important role in landslide control. However, owing to a limitation in the slide–resist design concept, large landslides are difficult to control. Moreover, the displacements of controlled projects are significant. In this paper, we propose an improved anti-slide pile design concept that develops and utilizes the landslide body. On this basis, we also design an arm-stretching-type anti-slide pile structure. We establish formulas for calculating the internal forces of this structure. The results of a case study indicate that the maximum shear force and bending moment of the arm-stretching-type anti-slide pile body were reduced by 43.6% and 25.4%, respectively, compared with those of a conventional single pile. Furthermore, the results of numerical modeling indicate that the arm-stretching-type anti-slide pile could significantly reduce landslide displacement. Thus, the proposed design is expected to solve the problems encountered when using conventional anti-slide piles for landslide control and can thereby become widely applicable in practice.

Interaction mechanism of the anti-slide pile and sliding mass based on the soil arching effect

Anti-slide pile has been one of the most used preventive measures for the landslide treatment in the recent years. The pile spacing has a significant impact on the arching effect which develops due to the relative compressibility of soil relative to the anti-slide piles. To reveal the interaction mechanism of pile and soil, the soil stress behind the anti-slide piles was studied based on the stress analysis of a semi-infinite plate. The influencing factors, such as time, pile spacing, and pile number were considered for the soil arching effect determination. A new method for determining the maximum pile spacing was presented, based on the Mohr-Coulomb failure criterion and the ultimate equilibrium method. The stress nephogram behind the anti-slide piles was obtained, and different distributions of soil arches, including the hyperbolic arch, extended shoulder arch, inverted bell arch, and circular arch were observed to be influenced by both the pile width and spacing. For the same pile width, the additional stress of soil decreases with the increase in the pile spacing. However, for the same pile spacing, a less apparent soil arching effect was observed when the pile width was smaller. This work can provide a simple solution for determining the soil stress and maximum pile spacing for the anti-slide pile design.

A CASE STUDY ON CAUSATION OF THE LANDSLIDE IN PORONG-SIDOARJO FOR ROAD CONSTRUCTION WITH HIGH EMBANKMENTS ELEVATION

Landslides occur in virtually every region of the world under diverse environmental conditions and topographies. These events negatively impact humans, resulting in countless casualties. Therefore, this research aims to determine the causes of landslides on man-made national road embankments in East Java, Indonesia. In addition, the occurrences at high elevations, despite reinforcement with soil retaining walls and group pile foundations, appear to be major sources of concern. In the present study, back analysis is conducted to evaluate the conditions of soil subgrade, existing pile capacity, and the effects of groundwater table on embankment stability, as slides typically occur after intense rainfall. Moreover, a stability analysis is carried out using the limit equilibrium process, and the embankment capacity assessment incorporates the anti-slide pile design method. The results show that the landslides are caused by varying soil depths. However, in a landslide embankment section, the soft soil depth appears deeper, compared to the middle zone, where soil data are employed in the existing reinforcement design. Furthermore, the overall stability evaluation for sliding requires wider application in anti-slide pile planning to complement the passive/active stress assessments on the retaining wall. Planning for anti-slide pile design is more often done using active and passive pressure calculations compared to overall stability calculations. Therefore, the results of this study can be used as suggestions for further planning, especially those related to overall stability.

Influences on Antislide Piles Used for Slope Reinforcement: Numerical Simulation Based on the Soil Arching Effect

This study explores the pile-soil interaction mechanism and the optimal use of antislide piles for slope reinforcement based on finite difference numerical modelling. The force and displacement principles of slopes and antislide piles are analysed. The influences of various factors are investigated, such as postpile filling parameters, pile embedding methods, and pile cross-sectional shapes. Numerical modelling is used to determine the optimal layouts of antislide piles for push and traction landslides. The findings indicate that the cohesive force of the fill has a greater influence on the piles and slope than the friction angle and is the primary control factor. Fully buried antislide piles provide a better antisliding effect than semiburied ones. With fully buried piles, the best controlling effect is obtained when the ratio of the length of the pile’s free section to the height of the sliding body is approximately 4/5. Moreover, stepped-cross-section piles provide better slope reinforcement than those with rectangular, T-shaped, or trapezoidal cross-sections. In practical applications, end-bearing arches can be utilized as the primary control structures, with friction arches used for secondary control to improve the soil arching effect as much as possible, thereby enhancing the stability of the piles and slope. To control landslides of various thrust forms, antislide piles should be set in the active section, the core sliding section, or both, as required. This paper provides guidance for improving the design of antislide piles.

Investigation of internal force of anti-slide pile on landslides considering the actual distribution of soil resistance acting on anti-slide piles

Frequent landslides have generated huge security threats and economic losses all over the world. As an important anti-slip retaining structure, anti-slide piles can maintain the slope stability. The distribution of soil resistance acting on piles is the critical factor influencing the design of anti-slide piles, and the method of calculating the internal force is directly related to the landslide treatment and construction cost. However, limitations in the method of calculating the internal force of anti-slide piles still exist. In this paper, the influence of the internal force of anti-slide piles both considering and ignoring the soil resistance acting on the piles was verified using ABAQUS software, revealing that the soil resistance indeed had a significant effect on the anti-slide piles, especially when the gradient of the soil before piles was less than 40°. Therefore, the formula for calculating the internal force of anti-slide piles was proposed considering the soil resistance. Based on this formula, the optimum quantity of steel reinforcement and the safety factor were compared in practical slope engineering. This proposed formula considering actual distribution of soil resistance can be used for approximate calculation for anti-slide piles, which can reduce the construction cost, especially in large and neutral landslide engineering.

Deformation Control Method of the Antislide Pile under Trapezoidal Load in the Zhangjiawan Landslide

Antislide piles are set in the Zhangjiawan landslide area, where the general features of the bedrock below the slip surface include upper weak and lower hard strata. Based on a site investigation, the horizontal displacement of the antislide pile head is 14.8 cm, which is not conducive to the stability of the landslide. In the study, a displacement calculation method for the pile under trapezoidal load is proposed for a colluvial landslide controlling. Furthermore, factors affecting the deformation and internal forces of the pile were also studied. The results indicated that (1) when the embedded length of an antislide pile increases, the horizontal displacement on the pile and maximum absolute shear force decrease, while the bending moment of the pile exhibits opposite trends; (2) the relationship between maximum shear force and maximum bending moment is linear with increasing driving force of landslide; and (3) increase in the ratio of the driving force between the pile head and slip surface (q0/q1) steadily increases the horizontal displacement of the pile. The relationship between the distribution of the driving force (q0/q1) and the reasonable embedded length of a pile is a quadratic function, which can be used to determine the reasonable embedded length of a pile under the action of rectangular or triangular loads. It is very useful to use the above method to guide the design of antislide piles in similar areas.

The Force Analysis of Anchor Anti-Slide Pile in Slope Reinforcement under Seismic Load

The force affect factors of anchor anti-slide pile in slope reinforcement under seismic load are studied in this paper. First of all, the method of dynamic analysis is introduced in FLAC3D. At the same time, seismic wave is selected in seismic dynamic analysis. Then, the sensitivity influence of anti-slide pile design parameters on dynamic contact stress, shear force and dynamic bending moment is analyzed by applying the seismic wave, giving the most significant effect factors of the dynamic contact stress and dynamic moment. In the end, the distribution regular of the contact force and the pile body stress under earthquake action is analyzed by selecting a case, laying a theoretical foundation for the further study of the dynamic performance of the reinforced slope.

A novel approach for determining landslide pushing force based on landslide-pile interactions

The distribution of soil pressure in landslides above anti-slide piles is a key factor in their design. The paper describes the evolution of stresses near soil-piles by testing a physical scale model during progressive loading. Displacement monitoring data on the surface of the landslide during loading discloses four main evolutionary stages: the initial stage of deformation, the uniform deformation stage, the accelerating deformation stage, and the damage stage. During initial deformation, the vertical distribution of soil pressure above anti-slide piles is sigmoidal, with the highest pressures occurring in the middle and upper parts of the slide mass. Next, during the uniform deformation stage, the soil pressure begins to assume a parabolic shape in a vertical profile, and this shape is fully realized during subsequent accelerating deformation. Finally, during the damage stage, the soil pressure relaxes to low values near the center of the slide mass, effectively inverting the parabola. Thus, the distribution of soil pressure above anti-slide piles changes in a complex manner during deformation, and these effects must be accommodated in the analysis and design of anti-slide piles.

Research on Stability Analysis of Soil Slope in Consideration of Creep Property

The Viscoelasto-Plastic Model with Double Yield Surface is introduced in detail. Finite element equations are introduced when the deformation is considered under Coupled Deformation and Seepage Fields. The response of one soil slope is simulated during rapid drawdown of water level by FEM. The results calculated show that the critical slip surfaces and safety factors by two ways are pretty close. To assure the safety of the slope, the design of anti-slide piles is carried out. Those ways used may provide reference to engineering practice.

Sensitivity Analysis of Shear Stress between the Landslide and Pile

There are many factors which can affect the mechanical properties of interface .Targeted research about effect anti-slide pile design parameters act on the contact stress is carried out in this paper. Based on the specific slope example and the principle of orthogonal experiment, the effect that the pile spacing (s), pile cross section width (b), pile cross section length/ width (h/b), the pile length (L) conduct on the maximum shear stress between the landslide and anti-slide pile is thoroughly discussed by combining with orthogonal design method and numerical simulation organically. The results show that (1) The order of influence factors respectively is L, S, b, h / b for the maximum shear stress on interface in the front of pile, and it is L, b, S, h / b for the maximum shear stress on behind of pile;(2) L is the main factor that affects the maximum shear stress on the interface between anti-slide pile and soil;(3) Effect about S and L acting on maximum shear stress of the interface respectively is significant and very significant; h/b has no significant effect on maximum shear stress of the interface.

Stability Analysis of Soil Slope and the Design of Anti-Slide Piles during Unsteady Seepage

Principle of calculation of water and earth pressures together by Limit Equilibrium Method (LEM) is introduced, and coupled deformation and seepage analysis is conducted by Finite Element Method (FEM ).The response of one soil slope is simulated during rapid drawdown of water level by LEM and FEM. The results calculated show that seepage upraises the critical slip surfaces, and critical slip surfaces and safety factors by two ways are pretty close. To assure the safety of the slope, the design of anti-slide piles is carried out. Those ways used may provide reference to engineering practice.

Numerical Simulation of the Forming and Failure Process of Soil Arching Between Anti-slide Piles

The mechanism of soil arching effect is important for anti-slide pile design. With the 2D particle flow method (PFC2D), the forming and failure process of the soil arching between anti-slide piles are simulated. The results show that the forming mechanism of soil arching mainly depended on stress transit process of micro soil granule. In the anti-slide pile numerical models (PFC2D), the contact stress transit trace lines present the tree crown shape, which centered about the anti-slide pile. The load from far field is transited to the front and side part of piles through the compress soil. When the soil between anti-slide piles collapses, the failure surface presented the arching shape. The cross-section and spacing of anti-slide piles affect the soil arching shape strongly. With the same pile spacing and soil parameters, the ultimate bearing capacity of rectangular cross-section pile is larger than the circle cross-section pile.