Active Earth Pressure Research Articles

Novel Application of a Swift-Assembled Support Method with Prefabricated Corrugated Steel for Vertical Shaft Excavation in a Metro Station

For the construction of a subway station, temporary vertical shafts were commonly used to facilitate machine operation. In densely urban areas, the requirement of settlement control and environmental impact called for a novel construction method of vertical shafts. In this paper, a novel swift-assembled support (SAS) structure and construction method for vertical shafts of a metro station was proposed, using prefabricated steel components. A comprehensive scheme of full-time monitoring was conducted to evaluate the performance of this novel support structure and ground response. Field monitoring results indicated that the SAS method was able to control the settlement of ground and adjacent buildings. Based on the field measurements, the calculation theory for design parameters were discussed. The active earth pressure yield from the method considering wall movement was closer to the field measurements. All of the local buckling values were both overestimated based on the technical standards’ methods. The calculation methods were thereby adopted carefully to determine the designed loading share ratio of structure components. The advantage of the SAS method, including rapid construction, safety, and lower environmental impacts, were obviously clear.

Analysis of the Active Earth Pressure of Sandy Soil under the Translational Failure Mode of Rigid Retaining Walls Near Slopes

Analysis of the Active Earth Pressure of Sandy Soil under the Translational Failure Mode of Rigid Retaining Walls Near Slopes

Examining Active Earth Pressure: Translational Mode Impacts on Cantilever Retaining Walls with Relief Shelves

Examining Active Earth Pressure: Translational Mode Impacts on Cantilever Retaining Walls with Relief Shelves

Deformation-related earth pressure within grid wall-pattern foundation under adjacent surcharge

This study investigated the deformation-dependent earth pressure evolution on the periphery of the grid wall-pattern foundation fully embedded into soft ground. The numerical modelling was performed using the embedded Modified Cam Clay Constitutive model in the FLAC3D software platform and numerical results were validated using centrifuge results. The induced effective vertical and horizontal stresses acquired from the numerical modelling were used to compute the corresponding deformation-dependent earth pressure at different buffer zone distances and surcharge loading. Thereafter, the parameters that influence the determination of the lateral displacement, induced effective vertical stress and deformation-dependent earth pressure coefficient were investigated using machine learning and genetic programming was used to establish the physical equations that could be used to estimate parameters for similar problems. Moreover, for the deformation-dependent earth pressure to be within Rankine's active and passive earth pressure the buffer zone distance/depth ratio should be 10% of the grid wall-pattern foundation embedment into the ground. Furthermore, it was also discovered that the structure fully embedded into the ground under adjacent loading cannot only be designed based on Rankine's active and passive earth pressure investigation on the periphery but the evaluation should be done within the entire location of the grid wall foundation.

Calculation method for static and seismic active earth pressure on counterweight retaining walls under translation based on two critical slip surfaces

The counterweight retaining wall with polyline wall back is a kind of gravity walls, which can be alternatively used in high embankments. To completely analyze active earth pressure on the polyline back under the wall translation mode, a comprehensive method is proposed based on two planar slip surfaces in the retained soil, an inclined slice method within the frame of limit equilibrium, and the pseudo-static approach. Meanwhile, the two critical slip surfaces include the global and local ones in the soils behind the whole wall and only the upper wall, respectively; and mobilized shear strength coefficients on interslice surfaces are introduced to fully consider the interslice shear forces. Some examples show that the proposed resultant forces on the whole wall are close to the experimental and numerical results generally within 10% error. The dip angle of backfill surface has a significant effect on the two slip surfaces, and the inclination of the lower back mostly influences the global slip surface. The unloading effect of the platform on the lower earth pressure becomes obvious as the upper wall lengthens under a constant height of the whole wall. The magnitude and profile of the seismic earth pressure on the polyline back are greatly influenced by the seismic coefficients.

The Performance of a Circular Excavation Supported by a Prefabricated Recyclable Structure in a Full-Scale Test

Excavations for underground structures, such as working shafts, underground grain silos, and parking garages, are characterized by uniformity, consistent dimensions, large quantities, and strict timelines. Prefabricated recyclable supporting structures (PRSS) are gaining attention over traditional retaining structures due to their standardized design, efficient construction, and reusability, which suit such excavations better. To validate their performance, full-scale tests are conducted to analyze the deformation and stress characteristics of PRSS. The results show that the average maximum lateral displacement of supporting pile is 0.07% of the excavation depth (He), roughly half that of steel plate. Differences in ground surface settlement behind steel plates and the supporting piles are not as significant as those in their lateral displacements. While the displacement of the supporting piles is insufficient to induce soil movement into the active limit state on the non-excavation side, the circular excavation’s arching effect reduces the earth pressure on this side of the supporting piles below the active earth pressure limit. Furthermore, the earth pressure acting on the steel plates is lower than that acting on the supporting piles, suggesting the presence of a soil arching effect between two adjacent piles. These findings offer valuable insights for guiding the construction of PRSS.

Active Earth Pressure on the Rigid Support Structures of Excavations Parallel to Tunnel Construction

Active Earth Pressure on the Rigid Support Structures of Excavations Parallel to Tunnel Construction

Soil structure interaction studies on earth retaining wall

Abstract The paper offers a brand-new analytical technique for figuring out retaining wall natural frequencies, which are essential for seismic design. Using translational and torsion springs to account for soil-backfill interaction and foundation flexibility, the approach applies the theory of beams on elastic foundations. There are three closed-form techniques offered for figuring out the natural frequencies of flexural and stiff modes. The analytical model takes into account several kinds of retaining walls and the interactions between soil and structure that go along with them, such as active, passive, and dynamic earth pressures. To make the analysis simpler, certain assumptions are made about the behaviour of the structure and the state of the soil. The suggested technique provides a trustworthy means of assessing retaining wall behaviour during seismic events, which is crucial for guaranteeing structural stability and averting failure.

Active and Passive Lateral Earth Pressure with Anisotropic Seepage Effect

Active and Passive Lateral Earth Pressure with Anisotropic Seepage Effect

Active Earth Pressure Calculation of Equilateral Convex Corners in Excavation Engineering

Active Earth Pressure Calculation of Equilateral Convex Corners in Excavation Engineering

Optimization of Technical Calculation of Precast Wall Application for Kawo Secondary Canal Improvement in Sempor Irrigation Area, Kebumen, Central Java

This study aims to perform technical calculations using precast lining in the repair of secondary channels. The planning data used included a concrete grade of fc 18.68 MPa and a reinforcement grade of fy 500 MPa. The service condition analysis was carried out by taking into account the loading during the most critical condition, where the channel is empty and active soil pressure and external water pressure are the main loads. The fixed load calculation was the main focus, where the active earth pressure (PD) was calculated by considering the soil-specific gravity, soil shear angle, and soil coefficient. The calculation results show that the PD reaches 12.24 kN, which gives an idea of the load that the structure has to bear. Furthermore, the internal force analysis provides a deeper understanding of the moments occurring at specific points in the structure. For example, the maximum negative moment at point A was calculated by considering the moments due to fixed load and transient load, which reached 12.73 kNm. This research contributes to improving efficiency and safety in the application of precast lining for secondary channel improvement.

Bearing capacity of modified suction caissons in clay overlying sand under monotonic horizontal loading

The modified suction caisson (MSC) is an innovative foundation for fixing offshore wind turbines, consisting of an internal caisson (IC) and an external skirt (ES). In this study, the Plaxis3D is conducted on the bearing capacity of the MSC in clay overlying sand under monotonic horizontal loading. The parameters of the aspect ratio of the IC, the size of the ES, the clay thickness, and the soil strength are considered. Results show that the horizontal ultimate bearing capacity of the MSC decreases as the length ratio of the ES to IC decreases. Moreover, the width of the ES enhances the horizontal bearing capacity of the MSC higher than the length of the ES. With the increase of the clay thickness, the rotation center of the TSC and MSC exhibits two and three stage change patterns, respectively. When the clay and sand are the inhomogeneous soils, the horizontal ultimate bearing capacity of the MSC is enhanced by 8.96% compared to the homogeneous soils. Additionally, the passive and active earth pressures around the MSC are mainly generated at the front and rear side of the loading direction, respectively. This study will provide theoretical guidance for the design of the MSC.

Experimental research of a flexible retaining wall model in laboratory conditions

Introduction. The Russian standards determine the lateral earth pressure at the failure surface stage, which corresponds to the Coulomb’s theory. In this case, the limit values of earth pressure on the flexible wall remain independent from the nature and intensity of deformation of the retaining structure. Therefore, computational methods for retaining walls are to be improved considering the above-mentioned factors.Aim. To obtain experimental data in order to develop a computational method for determination of the active earth pressure on retaining structures depending on their deformations.Materials and methods. Experimental tests were carried out by physical simulation for various models of flexible retaining walls using a purpose-designed laboratory test bench. Medium sand was used as a model backfill soil; its physical properties were determined under laboratory conditions in accordance with State Standard 5180-2015.Results. The tests provided data on the character of backfill soil deformations within the wedge of failure for different kinematic conditions of the retaining wall model and, accordingly, justified the application of inclined block phenomenological model, used to develop a computational method for determining the active earth pressure on retaining walls.Conclusions. Experimental tests indicate the correlation between deformation nature of the backfill soil and accepted conditions of soil operation during the development of engineering method for determining the lateral earth pressure. The obtained experimental data can be used in adoption and verification of the suggested computational method that enables shoring of excavations to be designed more reasonably in mutual conformity with the actual earth pressure diagrams.

Stability Investigation of Fully Recycled Support System of Steel-Pipe-Anchored Sheet Pile in Soft Soil Excavation

As a temporary project, the supporting system of excavation often encounters issues such as the waste of support components, environmental pollution, and high carbon emissions. This article presents a foundation pit support technology that utilizes steel tube anchorage sheet piles, which can be assembled and fully recycled. The composition of the support system is also introduced. Furthermore, a large-scale model test of steel-pipe-anchored sheet piles was designed and implemented. The displacement of each component of system and stability during excavation were investigated using 3D finite element modeling and analysis. The study results indicate that the deformation and failure mode of the model foundation under the steel-pipe-anchored sheet pile support system are closely related to the distance between the pipe pile and the sheet pile. When the distance is 10 cm, both the pipe pile and the sheet pile tilt simultaneously. When the distance is approximately 30–50 cm, the sliding surface becomes exposed from the position of the pipe pile. At distances up to 100 cm, the sliding surface is exposed between the pipe pile and the sheet pile. The anchoring effect of pipe piles and tie rods can effectively reduce the horizontal displacement of the sheet pile itself. The horizontal displacement at the top of both the pipe pile and sheet pile remains consistent throughout the excavation period of this model foundation. During excavation, measured earth pressure on the sheet pile is less with theoretical active earth pressure. After excavation, the maximum horizontal displacement of the top of the pipe pile exhibits a hyperbolic relationship with excavation depth.

Comparison of Design Requirements for Non-Anchored and Anchored Sheet Piles as Retaining Wall in a Basement

The construction of a 9-meter deep basement on clay soil with a soft consistency necessitates the use of a sheet pile for soil retention. Selected due to the soft soil conditions and a high groundwater level at the site, the sheet pile effectively addresses these challenges. The design calculations for the sheet pile, based on the Terzaghi concept, incorporated both active and passive earth pressures determined using the Rankine method. Analysis revealed a lateral force of 19,624 t/m² at a depth of 9 meters. The resulting design specifies a 10-meter embedded concrete pile without anchors, requiring a total sheet pile length of 19 meters. The chosen sheet pile type is W-600 A-1000. Alternatively, with anchors, the design calls for a 4-meter depth using type W-325A-1000 concrete sheet pile, with one anchor installed at a depth of 3 meters. The anchor's tensile strength is 5.46 tonnes, resisting a force of 113.817 Tm with a diameter of 5 cm. Modelling analysis showed that unanchored sheet piles have a safety factor of 0.770 and exhibit lateral deformation of 0.00803 meters. Conversely, the addition of anchors enhances the safety factor to 1.146 and increases lateral deformation to 0.0195 meters, indicating that anchors significantly improve safety and reduce deformation.

The Behavior of Concrete Cantilever Retaining Walls During Far-Field and Near-Fault Earthquakes

Abstract The dynamic behavior of retaining walls is a complicated subject and a considerable design challenge, particularly under seismic conditions. Seismologists and investigators have an interest in near-fault earthquakes with significant velocity pulses because it can cause considerable displacements in constructions with respect to far-field earthquakes and consequently rise the hazard of earthquake-caused failure of structures. Despite there are several studies have investigated the seismic behavior of retaining structures, but the researches about retaining walls subjected to the influence of near fault like pulse earthquakes is still not adequate. The current study targets to numerically assess the dynamic performance of concrete cantilever retaining walls during far field ground motions (FFGMs) and near-fault ground motions (NFGMs). The nonlinear analysis of time history is conducted using the finite element method for three cantilever retaining wall models. The results of the analysis gained in terms of top horizontal displacement of the wall, active seismic earth pressure, and acceleration response of the system, which have been considered to recognize the impact of near fault earthquake on retaining structures. Additionally, the influence of different PGA of NF and FF earthquakes has been studied.

Active failure mechanisms and earth pressure of narrow backfill behind retaining structures

Through a series of model tests accomplished by particle image velocimetry analyses, this study presents the visualisation of the displacement field of narrow soil behind retaining structures under translational mode. The progressive development of failure mechanisms and active earth pressure are measured in the process of tests. Finite-element limit analyses are additionally carried out to investigate and verify the ultimate failure mechanism and active earth pressure acting on retaining structures. Furthermore, this study carried out analyses on the development of failure mechanisms and active earth pressure with different aspect ratios, inclinations of the existing structure and backfill surface surcharge. A reasonable agreement was observed between experimental and numerical results. With an increase in backfill spacing, the failure mechanism of backfill turns from reflective shear bands into a single shear band, and the earth pressure exerted on the retaining structure increases.

Internal variable gradient model for active earth pressure of rigid retaining wall moving with translation

The instability of retaining wall is a key factor for many geo-hazards, such as landslides. To estimate the stability of retaining wall, the distribution of earth pressure is necessary. The results of in-situ observations and indoor experiments demonstrate that the distribution of earth pressure behind the retaining wall exhibits remarkable nonlinearity. When the results are analyzed in details, the oscillation and quasi-periodicity of the distribution of earth pressure are observed, which has not been given widely concerns and cannot be described by the existing analytical models. Based on the internal variable gradient theory and operator averaging method, a gradient-enhanced softening constitutive model is proposed in this paper to describe the oscillation and quasi-periodicity of the distribution of earth pressure acting on the retaining wall, by introducing the high-order gradient terms of the hydrostatic pressure into Mohr-Coulomb yield condition. In order to check the applicability of the proposed formulation, the predictions from the formulations are compared with the full-scale and laboratory-scale test results as well as the existing formulations. It is noted from the comparisons between predicted and measured values that the results of gradient-dependent softening constitutive model provides the comparable approximations for active earth pressure and describes the oscillation and quasi-periodicity very well. This model may enhance the comprehension of soil mechanics and provide a novel view for the design of the retaining wall.

Numerical Investigation of Seismic Behaviour for a Flexible Cantilever Retaining Wall with Cohesive Backfill

In the seismic design of flexible cantilever walls retaining cohesive backfill soil, the common practice is to neglect the cohesion effect. Dynamic lateral earth pressure is typically evaluated based on approaches primarily intended for cohesionless soils or through analytical pseudo-static methods. Nevertheless, both experimental and theoretical evidence has demonstrated significant effects due to soil cohesion that are not accounted for by these methods. This study involved finite element modeling (FE) of a flexible cantilever wall with a height of 5.4m, supporting homogeneous cohesive backfill under initial static and seismic loadings. The calculated active earth thrust was then compared with values obtained experimentally and through conventional analytical methods. The obtained results indicate that the presence of soil cohesion significantly reduces seismic demands on flexible cantilever retaining walls, resulting in a substantial reduction of seismic active earth pressures and total seismic thrust by up to 50% and 52%, respectively. It enhances also the overall stability of the system by shifting the point of application of seismic thrust toward the base of the wall, thereby increasing the safety margin. In addition, it significantly decreases the wall displacement at the stem top, with reductions of up to 104% compared with the case involving cohesionless backfill. It was observed that the conventional methods recommended by some seismic regulations largely underestimate seismic active pressure.

Failure Mechanism and Active Earth Pressure of Narrow Backfills behind Retaining Structures Rotating about the Base

Failure Mechanism and Active Earth Pressure of Narrow Backfills behind Retaining Structures Rotating about the Base