Secant Pile Wall Research Articles

Parametric and comparative study between anchored, strutted and cantilever system for a secant pile wall retaining a soil during construction an under-ground water tank

In the present study used numerical analysis to investigate the lateral displacement of secant pile walls and ground surface settlement problems for a case study. Three structural systems were modelled, analyzed, and designed to determine the best solution for each case: cantilever, anchored, and strutted secant pile wall (SPW). Field data from a case study were used to examine the lateral displacement and ground surface settlements of the strutted secant pile wall. Plaxis finite-element software was used to create a plane-strain numerical model. The findings of the numerous simulations performed are compared to field data, which shows very strong coherence.

Predicting the Maximum Axial Capacity of Secant Pile Walls Embedded in Sandy Soil

Predicting the Maximum Axial Capacity of Secant Pile Walls Embedded in Sandy Soil

Numerical Modelling of Secant Piles

This study presents numerical modeling of a secant pile wall and investigates the lateral displacements, as well as the pressure exerted on the secant pile wall due to the existing soil. The analysis was performed using a finite element method software package, which simulates the behavior of the soil-pile interaction system under various soil conditions. The numerical model considers the geometrical and material properties of the soil, pile, and concrete infill, as well as the effects of water pressure, soil swelling, and ground movement on the stability of the wall. The results of the analysis show that the secant pile wall is capable of resisting the expected lateral and vertical loads, and earth pressures, and the deflection of the wall is within the acceptable limits. Furthermore, the study investigates the effects of different design parameters on the performance of the secant pile wall, including the spacing and diameter of the piles, the thickness and strength of the concrete infill, and the soil properties. The findings of this research provide valuable insights into the behavior and performance of secant pile walls, which can help engineers and contractors to improve the safety and efficiency of deep excavation projects in urban environments.

Variation of the Hydraulic Conductivity and the Mechanical Characteristics of Plastic Concrete with Time

Sand-bentonite-cement are commonly used as cut-off walls to isolate polluted soils or in ground improvement technologies and as retaining structures as secant pile wall. In this research, a laboratory program consisted from 105 sample were prepared and tested between different tests, such as hydraulic conductivity, porosity, and compressive strength to monitor the mechanical behavior of sand-bentonite-cement at different ages. Based on the experimental relationships between hydraulic conductivity coefficient and samples age; there were reduction due to added bentonite to mixture reach about 35.0% at 7 days. Moreover, the average reduction in the compressive strength of plastic concrete samples with bentonite was lower by average range about 51.0% than the compressive strength of plastic concrete samples without bentonite at 7 days. In this study, proposed formulas were derived to estimate the splitting tensile strength based on the compressive strength and the hydraulic conductivity in terms of the bentonite/cement ratio and testing age. The predicted values showed well agreement with the experimental records for samples of sand-bentonite-cement mixtures where the standard deviation and coefficient of variation were 0.02, and 0.94%, respectively.

Performance Analysis of Axially Loaded Secant Pile Wall Embedded in Sand: An Experimental Investigation

In urban environments, temporary excavation support systems (ESSs) are intensively recommended during the construction process of structures with underground levels to preserve nearby structures and maintain the excavation sides. Once the foundations and basements are constructed, these systems are rendered useless. As a result, integrating the temporary ESS into the building foundation may have significant benefits. Therefore, the main aim of this paper was to investigate the behavior of Secant Pile Walls (SPWs) through fifteen model tests with an acceptable scale on an axially loaded SPW embedded in medium and dense sand. This study considered several factors to define wall behavior, such as normalized lateral deflection (δh/Ht%), the vertical deflection of the SPW (δvw/Ht%), vertical ground settlement (δv/Ht%), and settlement influence zone (Do). These factors were investigated and analyzed under the influence of a set of parameters including normalized penetration depth (He/Hc), sand relative density (Dr), and surcharge load density (Wsur). The findings demonstrated that SPWs had structural and overall stability features to withstand lateral earth pressures as well as applied axial loads. Generally, increasing the He/Hc ratio further than a limit value of 2.0 for the same surcharge load had a limited impact on the ultimate axial capacity, particularly in the case of dense sand. The location of the pivot point (ε′) extended from 0.24 to 0.41He from the wall tip, with a mean value of 0.34He and 0.29He for the values of Dr = 80 ± 2%, and 60 ± 2%, respectively. Other issues were also discussed for selected samples, including an analysis of the wall's bending moments and any potential wall buckling. Finally, to correlate the experimental data with the theoretical values, a modification factor for the pile static formula was developed by using nonlinear regression analysis with a significant prediction accuracy with an R2 of 0.94.

Study of the Secant Pile Wall technique, its application and Sustainable Construction Using the Non-Biodegradable Waste as partial replacement for Concrete materials

The planning and execution of the project of a Secant Pile wall are presented in this study. Secant pile walls are a type of embedded retaining wall that allows for excavation of great depths in water-logged terrain and soft sub stratum. To construct the walls, pilings are placed in a certain order. Soft piles are set first, then hard piles are laid on both sides, overlapping and cutting through the soft piles. This design can also be utilised as a cut-off wall for fine sands and very soft wet soils.In light of the significant growth, the idea of using non-biodegradable trash in concrete is also incorporated. Many non-biodegradable wastes exist; this study includes research on the potential reuse of ceramic waste, plastic granules, and glass trash as partial replacements in concrete materials. These waste materials are collected in various percentages and replenished using the cited publications. The properties of concrete containing the appropriate waste material are investigated.

Liquefaction mitigation methods for existing shallow-founded elongated structures on horizontal or mildly-inclined ground

This numerical study investigates the effectiveness of selected ground improvement methods for existing elongated structures that are shallow-founded on horizontal or mildly-inclined liquefiable ground. It employs non-linear dynamic fully coupled 2D ground response analyses performed with the finite-difference method. When the mildly-inclined ground remains unimproved, narrow structures prove more susceptible to horizontal displacement and rotation than wide structures with the same load. However, settlements develop regardless of the width of the structure and the (mild) inclination angle of the ground. Focusing on the improvement of existing structures, the paper studies prefabricated vertical drains or stiff containment walls implemented solely at their perimeter. Reinforced concrete walls (diaphragm or secant pile walls) prove much more effective in reducing structural settlements, horizontal displacements and rotations than prefabricated vertical drains, provided that their tip reaches the bottom of the liquefiable layer. Constructing these walls with deep soil-cement mixing proves a viable (less costly) alternative, at least for horizontal ground conditions.

Impact of ground conditions and excavation depth on selection of excavation support system

Inappropriate selection of an excavation support system (ESS) may lead to delays, cost overruns and quality and safety problems. Soil conditions, excavation depth and groundwater level are important factors that significantly affect the selection of ESS. However, a guideline that determines the effects of these three factors and accounts for their variation in the selection of ESS is not available. To evaluate such effects, a questionnaire was sent to excavation support experts worldwide. The results of the conducted survey are presented and discussed in the current paper to determine the favourable soil conditions and maximum excavation depths for ESS in dry and wet soils. The focus is on the soldier pile, secant pile, diaphragm and jet grout walls because of their common use worldwide. Clear guidelines that can help in the selection of an appropriate ESS for given site conditions could be established. The obtained findings are compared with the conditions and adopted ESS of reported case histories.

Structural behavior of small-scale reinforced concrete secant pile wall

PurposeTo predict the real behavior of the full-scale model using a scale model, optimized simulation should be achieved. In reinforced concrete (RC) models, scaling can be substantially more critical than in single-material models because of multiple reasons such as insufficient bonding strength between small-diameter steel bars and concrete, and excessive aggregate size. Overall, there is a shortfall of laboratory and field-testing studies on the behavior of secant pile walls under lateral and axial loads. Accordingly, the purpose of this study is to investigate the validity and the performance of the 1/10th scaled RC secant pile wall under the influence of different types of loading.Design/methodology/approachThe structural performance of the examined models was evaluated using two types of tests: bending and axial compression. A self-compacting concrete mix was suggested, which provided the best concrete mix workability and appropriate compressive strength.FindingsUnder axial and bending loads, the failure modes were typical. Where the plain and reinforced concrete piles worked in tandem to support the load throughout the loading process, even when they failed. The experimental results were relatively consistent with some empirical equations for calculating the modulus of elasticity and critical buckling load. This confirmed the validity of the proposed model.Originality/valueAccording to the analysis and verification of experimental tests, the proposed 1/10th scaled RC secant pile model can be used for future laboratory purposes, especially in the field of geotechnical engineering.

Hybrid AHP-Fuzzy TOPSIS Approach for Selecting Deep Excavation Support System

This paper introduces and further applies an approach to support the decision makers in construction projects differentiating among a variety of deep excavation supporting systems (DESSs). These kinds of problems include dealing with uncertainty in data, multi-criteria affecting the decision, and multi-alternatives to select one from them. The proposed approach combines the analytic hierarchy process (AHP) with the fuzzy technique for order of preference by similarity to ideal solution (fuzzy TOPSIS) in a multicriteria decision-making (MCDM) model. The MCDM model emphasize the ability to combine expert knowledge, cost calculations, and laboratory test results for soil properties to achieve the scope. The model proved it had a superior ability to deal with the complexity and vague data that are related to construction projects. Furthermore, it was applied to a real case study for a governmental housing project in Egypt. Secant pile walls, sheet pile walls, and soldier piles and lagging are selected and studied as being the most common DESSs and as they satisfy the project requirements. The model utilized four criteria and fourteen comparing factors, including site characteristics, safety, cost, and environmental impacts. Based on the results of the model application on the investigated case study, a decision was reached that using secant piles as a supporting system in this project is mostly preferred. Furthermore, sheet pile wall, and soldier piles and lagging, come next in the ranking order. A sensitivity analysis is carried out to investigate how sensitive the results are to the criteria weights. In addition, the paper discusses in detail the reasons and factors which affect and control the decision-making process.

On the use of both diaphragm and secant pile walls for a basement upgrade project in Vietnam

On the use of both diaphragm and secant pile walls for a basement upgrade project in Vietnam

ANALISA PERBANDINGAN PELAKSANAAN SECANT PILE DENGAN DIAPHRAGM WALL SEBAGAI PERBAIKAN PONDASI BENDUNGAN SEMANTOK

The Package I Semantok Dam Contruction Project is a project belonging to the Balai Besar Wilayah Sungai (BBWS) Brantas. In a dam to prevent seepage of water on the dam foundation, it is necessary to repair the foundation. The Semantok Dam uses the Secant Pile as a foundation repair. On the other side, there is another foundation dam repair, namely Diaphragm Wall which also has the same function as the Secant Pile. This Comparative Analysis of Secant Pile with Diaphragm Wall aims to compare the most efficient method with the required HSE, Time and Cost parameters. The data needed in the preparation of the Comparative Analysis are drawings of the Secant Pile and Diaphragm Wall work plans, technical specifications for foundation repair, and the unit price of the Nganjuk Regency work in 2021. The preparation of risk analysis in HSE uses HIRARC, the work schedule using Microsoft Project 2016 program and cost plan using Microsoft Excel 2019 program. The result of this comparative analysis is that Diaphragm Wall is more efficient in terms of implementation method, HSE, time, and also cost than Secant Pile. In the Secant Pile there are 43 accident risks, with a total processing time of 301 days, and the required cost is Rp. 198,009,706,092.05,. On the Diaphragm Wall there are 41 accident risks, with a total processing time of 74 days, and the required cost is Rp. 149,974,022,220.27,.

Excavation case study in Manhattan, NY with practical approach to predict ground movements

This paper presents the case study of the staged excavation for the New York University College of Nursing building in Manhattan, NY, supported by corner-braced secant pile walls. A commercial fini...

Lateral Deflection of Cantilever Secant Pile in Soft Clay

The performance of deep excavations is governed by the ground conditions such as soil stiffness and in situ stress conditions. Cantilever secant pile wall (CPW) is one of the retaining systems which are used to support deep excavation. Its lateral deflection has great importance as it shows the behavior of CPW in the soil. Two dimensional analysis (2D) and three dimensional analysis (3D) may be used to get the lateral deflection in numerical solution. This study is focused on 2D and 3D analysis for CPW in soft clay. The finite element software Abaqus/CAE-v6.9 has been used in the analysis. The 2D study analysis takes into account the different CPW depths and its diameter effect. The construction stages effect on the lateral deflection have been studied also. The 3D study analysis takes into account the different excavation geometry “the length and width of the excavation” effect, also different depths for CPW in 3D analysis have been studied also. The results showed that longer CPW has larger lateral deflection while CPW diameters have no effect on lateral deflection. Later deflection in one construction stage may be double that of previous stage. Also it was found that later deflection in three dimensional (3D) analysis is higher than the 2D analysis by three times. This confirms that 3D analysis of CPW in soft clay leads to more accurate results than 2D analysis.

Behavior of cantilever secant pile wall supporting excavation in sandy soil considering pile-pile interaction

This study presents the results of a numerical investigation performed to investigate the behavior of a cantilever secant pile wall (CSPW) used to support excavation in sandy soil. These types of excavations have the potential to cause severe ground movement and possible damage to the adjacent structures. A major concern in supporting excavation is to predict and control ground movement associated with excavation particularly in cohesionless soils, as it could trigger global instability and catastrophic failure. The magnitude and distribution of lateral earth pressure and ground movement depend mainly on soil properties, excavation depth, excavation plan geometry, the stiffness of the supporting wall, and the contact between the secant piles themselves. Three-dimensional finite element model has been developed in this study to capture the excavation and wall geometry. A parametric study has been performed using a wide range of sand density, excavation depth, wall flexural stiffness, and bonding between piles within the wall. The results allowed for the development of an approach to predict both the wall deflection for the case of fully and partially bonded piles. This will help engineers to predict ground movement and select an appropriate supporting system that can maintain the stability of the adjacent structures.

THE EFFECT OF LATERAL CONFINEMENT ON THE SETTLEMENT CHARACTERISTICS OF SHALLOW FOUNDATIONS ON SAND

Free to read on publisher website Today, most of the high rise buildings consist of basements as part of the substructure. Basement construction is usually supported by embedded type retaining walls such as secant pile walls or diaphragm walls. This provides lateral confinement and the performance of shallow foundations would be affected by this lateral confinement. In this study, the effect of lateral confinement on the settlement characteristics of shallow foundations on sand was studied experimentally and numerically. First, experimental investigation using small-scale laboratory models were carried out and the results were used to validate the finite element (FE), model. Changing the depth of lateral confinement and the distance to the edge of the shallow foundation from the lateral confinement, the stress immediately below the footings corresponding to a settlement of 25 mm was compared. Furthermore, the effect of lateral confinement due to embedded retaining wall on the settlement characteristics of a raft foundation on sand was also studied using the validated finite element model. In scaled physical models of confined foundations, there was an enhancement in allowable bearing capacity at the tolerable settlement with the increase in depth of embedment and the reduction of distance to the confinement. It was observed, for the study variables considered in this study that the bearing capacity can be improved up to 4 times by laterally confining the footing. However, in the analysis of confined raft foundations on sand, there was no significant change in bearing pressure for a 50 mm tolerable settlement with the change of study variables.

Strutting systems for deep excavations – technical challenges

Constant development carried out in town centres causes that many problems related to earthworks and tunnelling must be resolved. Investors are required to ensure respective number of parking bays, which in turn demands 2-3 storeys of underground car parks. This paper presents interesting case studies of deep excavations in Wrocław, Poland. As the geotechnical works in the old city centres may bring some risks to the surrounding area, proper strutting or anchoring systems must be provided. Apart from solving engineering problems, one needs to meet very stringent requirements of heritage conservator supervision. In order to ensure the stability of the excavation walls, it is necessary to examine the foundations of neighbouring structures, and if necessary, to strengthen them for the process of installing the excavation protection walls, progressing the excavations and constructing basement storeys. Another problem refers to constructing underground storeys below the level of groundwater. This requires efficient cutting-off or long-term lowering of water table inside the excavation with a possibly limited intervention in hydrological regime beyond the project in progress. In the typical case of old cities in river valleys such “hoarding off’ the excavation and cutting off groundwater leads to temporary or permanent disturbances of groundwater flow and possible local swellings. Contemporary technologies make it possible to protect vertical fault and simultaneously cut-off groundwater inflow by means of steel sheet pilings, diaphragm walls or secant pile walls.

Lateral earth pressures acting on circular shafts considering soil-structure interaction

Nowadays, there is a significant demand on developing and expanding the existing infrastructure which necessitates the implementation of fast and cost effective construction methods such as the secant pile walls. The secant pile walls constructed in a circular plan layout to form a vertical shaft provide unique advantages such as compression ring behaviour. Compression rings act as a single-unit system in resisting lateral earth pressure and converting loads from all directions to compressive forces which can be resisted only by low concrete strength. Secant pile walls require stringent drilling tolerances to be achieved in order to behave as a compression ring and to perform as an effective groundwater cut-off wall. This paper presents a parametric study that investigates various aspects of the behaviour of circular shafts constructed using secant pile walls. The aspects that are studied include the identification of the magnitude and distribution of earth pressures exerted on circular shafts by the retained material. The distribution of surcharge pressures on the shaft walls is also studied. The results showed that the surcharge pressures on the wall increased with increasing width of surcharge area; for example, the maximum surcharge pressure increased by at least 60% when surcharge width increased from W = 3 m to W = 48 m. In addition, the results indicated a decrease of the maximum surcharge pressure on the wall by almost 22% when shaft radius decreased from R = 5 m to R = 3 m for Soil 1. Unlike what is observed in plane strain conditions, distance between the surcharge and shaft wall was seen to have a small effect on the magnitude of maximum pressures. The results also showed that the theoretical estimate of pressures underestimated the calculated values at larger depths and that the horizontal extent of the spread of pressure around the shaft was significantly influenced by the type of soil as well as width of surcharge. The outcomes of this study address practical design concerns and are considered to be of interest to those involved in design and construction of vertical shafts.

Parametric Study on Analysis and Design of Permanently Anchored Secant Pile Wall for Earth Quake Loading

Due to space limitations in urban areas, deep excavation in to the ground has become a common practice worldwide. Deep excavations are supported by conventional retaining walls: sheet pile walls, braced walls, diaphragm walls and secant pile walls. An advantage of secant pile wall compared with other excavation supporting systems is that they are the most economical methods of creating an effective water control barriers for building structural walls. The analysis of these deep excavations requires considerations of; nonlinear, dynamic and involves consideration of soil parameters, deformation, interaction of soil and retaining configuration. Thus, in order to accurately describe the behaviour of the anchored secant pile for earthquake loading, 3D finite element simulation was applied. The study considering earth pressure, plastic analysis, and soil deformation was carried out. The analysis indicated that for 20 m excavation step in fourth stage, incremental lateral displacement was 55.2 mm and total displacement was 110.4 mm. The analysis indicated that the deeper the foundation, the larger the deformation. The real accelerogram of Loma Prieta earthquake at Del Valle Dam Station with moment magnitude 7.1 occurring at epicentral distance 66 (18 Oct, 1989) was used in the study. In order to accurately study the response of the anchored secant pile to earthquake loading; it is suggested to carry out the relevant tests to determine the right stiffness parameters. Further investigation on parameters (density and shear modulus) and other conditions that affect seismic analysis.

Seepage and pore pressures around contiguous pile retaining walls

Diaphragm and bored pile retaining walls are often used for the construction of basements, metro station boxes and cut-and-cover tunnels in urban areas. While diaphragm and secant pile walls are generally intended (and assumed in analysis) to be effectively impermeable, contiguous piles may allow through-the-wall seepage even when preventative measures have been undertaken. Provided the flow rates can be tolerated or dealt with, through-the-wall seepage should result in a reduction in pore water pressures behind the retaining wall compared with an impermeable construction, giving the potential for reductions in the depth of embedment and wall thickness, and hence cost. However, this potential is rarely realised owing to the difficulty in quantifying with sufficient confidence the hydraulic regime associated with a leaky retaining wall. This paper reports the results of laboratory investigations and numerical analyses carried out to assess the effect of the inter-pile gaps on the pore pressure distribution around a contiguous pile retaining wall. The results show that the pore pressures behind the piles reduce significantly as the pile spacing is increased. Long-term field monitoring confirms that the pore water pressures are much lower than would be expected for an impermeable retaining wall in similar soil. The applicability of a simple expression linking the pile diameter, pile spacing and the effective permeability of an equivalent uniform wall is demonstrated.