Contiguous Pile Research Articles

Estimating Max moment and shear exerted on contiguous piles subjected to earthquake using ANN.

Recently the usage of Contiguous piles in many different aspects of construction projects are become more common. Determination of the shear force and moment values exerted on the contiguous piles require extensive analysis and calculations especially when earthquake is to be encountered. ANN mathematical models for calculating this value combining 144 input sets that represent height of excavated (H), ratio of H to the depth of embedment (D), unit weight of retained soil ( ) and angle of internal friction ( ) is presented in this paper. The mathematical models obtained show acceptable regression and deviation. It was found that both shear and moment values subjected on the piles are decreases with the decrease of ( ) and increases with the increase of ( ). The height of excavation (H) was found as the most important input parameter that affects the output values of the models

An Experimental Study on Staged Excavation Supported by Contiguous Pile Wall

An Experimental Study on Staged Excavation Supported by Contiguous Pile Wall

Analysis and evaluation study of retaining wall structures in a building project in South Jakarta

Retaining wall type contiguous pile is a structure that serves to hold and stabilize the soil in certain soil conditions. Retaining walls can be deformed by various factors. This research on retaining walls compares the deformation results between the actual data, the finite element method with the Mohr - Coulomb, Soft Soil and Hardening Soil parameters, and find the safety factor based on SNI Geotechnical 8460:2017. The result of this research is that the deformation value of Mohr - Coulomb modelling is closer than the actual value in the field, followed by the modelling of Soft Soil & Hardening Soil, Soft Soil & Mohr-Coulomb, and Hardening Soil. This difference occurs because there are differences in the correlation approach and the type of undrained type used. It was found that the Mohr - Coulomb parameter is better than the other parameters with a deformation result of 24.5 mm with a safety factor of 1.675 which is close to the actual data.

A Detailed Investigation on Contiguous Pile Wall with Homogeneous Backfill

A Detailed Investigation on Contiguous Pile Wall with Homogeneous Backfill

Characterization of Scour-Induced Subsurface Deformations in Port Structures with Contiguous Pile Walls using Ground-Penetrating Radar (GPR)

Characterization of Scour-Induced Subsurface Deformations in Port Structures with Contiguous Pile Walls using Ground-Penetrating Radar (GPR)

Stability analysis of Contiguous pile

Nowadays in modern construction, large-scale structures with greater heights that need deeper excavation are more popular. At present, the new structures from residential buildings to commercial complexes are keen on adopting basement floors for more underground utilities. These new structures with the need for basements are going for deeper excavation close to the existing buildings surrounding the proposed site of construction. In this case, understanding the behavior of soil profile based on load-bearing capacity, settlement, density, and angle of friction are important to safeguard the adjacent structures from being damaged. Very often deep excavations are supported by pile wall systems. In the literature, it appeared that pile walls are analyzed and designed for active and passive earth pressures. Recent investigations paved the way for my research to consider and implement the contiguous piles based on soil-structure interaction to eradicate soil sliding from the adjacent large buildings during the process of deeper excavation at the worksite. In the present study, the pile is analyzed by considering active and passive earth pressures using Rankine’s theory and Brinch Hansen’s technique respectively. Together with passive earth pressure, horizontal subgrade modulus is also considered using Trezaghi’s concept. With these forces, the stability of the pile is analyzed using the STAAD. Pro software. For parametric study three different pile diameters of 0.45m, 0.6m and 0.9m are considered. Deflections, shear force, and bending moment of the pile are computed. It is inferred that 0.9m diameter pile wall is stable for the given loadings.

Soil Arching and Its Effect on Contiguous Pile Wall Subjected to Staged Excavation: Physical and Numerical Investigations

Soil Arching and Its Effect on Contiguous Pile Wall Subjected to Staged Excavation: Physical and Numerical Investigations

Stability of limiting pressure behind soil gaps in contiguous pile walls in anisotropic clays

New average FELA solutions for the problem of the limiting pressure behind soil gaps and the lateral force acting on a pile per unit length of a contiguous pile wall in anisotropic clay are investigated in this paper. The anisotropic undrained shear (AUS) model is utilized to determine anisotropic soil behaviour. The limiting pressure factor (N) is derived by varying dimensionless parameters such as the anisotropic ratio (re), the adhesion factor (α), and soil gap ratios (S/D) which are presented in the form of sample charts and tables. The failure patterns of the soil gaps are also conducted and explained in light of the impacting factors. Aclosed-form equation of the limiting pressure factor is presented in order to efficiently and precisely establish and evaluate an undrained limiting pressure behind soil gaps and the lateral force operatingon a pile wall in practice.

Behaviour of Contiguous Piles Group with Different Pile Diameters in Sandy Soil under Vertical Loading

Behaviour of Contiguous Piles Group with Different Pile Diameters in Sandy Soil under Vertical Loading

Behaviour of Contiguous Pile Group with Different Pile Spacing in Sandy Soil under Vertical Loading

Behaviour of Contiguous Pile Group with Different Pile Spacing in Sandy Soil under Vertical Loading

Composite contiguous pile wall and deep mixing column wall as a dam –Design, construction and performance

This paper presents a case study on the application of a composite contiguous-pile wall and deep mixing (DM) column wall as a dam to develop a luxury lake in Lake Legend Chaengwatthana project, Bangkok, Thailand. This dam was constructed in a deep rainwater pond without providing the water removal, which could save on both time and cost construction. The design and construction method were challenging because the dam was located on the soft and thick Bangkok clay. The dam was designed by finite element analyses (FEA) using PLAXIS software. The 2 rows of contiguous-pile walls were first executed and then filled with soft clay. The DM columns were used to strengthen the clay backfill. The FEA results at normal and rain-shortage stages confirm the stability of the dam with accepted deformation. With insignificant water seepage over time, the dam acted as the waterproof barrier. The field performance of the dam during construction and at service state over 276 days were recorded and compared with FEA results. The numerical simulation slightly over-predicted the lateral displacement. The difference in the displacement between the measured and simulated data reduced significantly with depth. The rate of consolidation by the numerical simulation results were slightly slower than that by the field measurement. The outcome of this research will be fundamental to develop a design guideline of ground improvement in soft Bangkok clay and other similar soft clay deposits especially in Southeast Asian countries.

Numerical Investigation of Soil Arching in Dense Sand

Soil arching is relevant in various engineering applications particularly in cases where there is relative movement between soil and structure. When a portion of the soil mass yields, redistribution of stresses take place between the yielding mass and its surrounding. Several trapdoor experiments have been performed with different improvements and extensions over the past few decades to study soil arching. Numerical modeling of a trapdoor mechanism is performed in this study and the suitability of Hardening Soil constitutive model over the Mohr-Coulomb model has been studied. In the present study, extensive parametric studies were conducted to examine the extent of the zone of influence and zone of yielding. The zone of influence, beyond which there is no influence of soil arching, is bounded by straight lines to form a trapezoidal shape. The dimensions of the influence zone depend on the fill height (H) and trapdoor width (B). The two families of failure surfaces, internal and external, are described and their categorization with respect to the H/B ratio is well explained. Furthermore, the zone of yielding and the region enclosed within limits of influence and failure planes are classified as active and passive zones, considering the dilation and compression in the direction of trapdoor displacement. The equilibrium of stress transfer in soil arching that remained as an unjustified assumption until now is systematically brought out in the present study. The present study also highlights salient characteristics of the plane of equivalent settlement and critical height. The present study throws some light on the need for further understanding of arching in various field applications, such as piled embankments, tunnels, culverts, buried pipelines, excavations supported by contiguous pile walls, and slopes stabilized by a row of piles.

Evaluation of excavation-induced movements through case histories in Hangzhou

Purpose Deep excavation in soft clay often causes additional deformations to surroundings. Then, if deformations cannot be predicted reasonably, the adjacent buildings may be threatened by the deep excavation. Based on the good field observations from ten deep excavations in Hangzhou, this paper aims to thoroughly investigate the characteristics of wall deflections and ground settlements induced by deep excavations. Design/methodology/approach On the basis of good field observation of ten deep excavations, the performances of excavations, supported by contiguous pile in Hangzhou, were studied, and also compared with other case histories. Findings The maximum wall deflections (dhm) rang mostly from 0.7 to 1.2 per cent He, where He is the final excavation depth, larger than those in Taipei and Shanghai. The observed maximum ground settlement in the Hangzhou cases generally ranges from 0.2 to 0.8 per cent He. Then, the settlement influence zone extends to a distance of 2.0-4.0 He from the excavation. The relatively large movements and influence zones in Hangzhou may be attributed to low stability numbers, large excavation widths and the creep effect. The excavation width is justified to have a significant influence on the wall deflection. Therefore, to establish a semi-empirical formula for predicting the maximum wall deflection, it is necessary to include the factor of excavation width. Originality/value The relevant literature concentrated on the characteristics of deep excavations supported by the contiguous pile wall in Hangzhou soft clay can rarely be found. Based on the ten deep excavations with good field observation in Hangzhou, the characteristics of wall deflection and ground settlements were comprehensively studied for the first time, which can provide some theoretical support for similar projects.

A Mathematical Model for Prediction the Embedment Depth of the Contiguous Piles Used in the Interchange of Zakho Entrance

Determination of the depths of the embedment of contiguous piles requires extensive soil investigation to obtain the soil physical parameters. In addition, a large number of such piles involved in restricted access projects make that depth an essential problem. A simple mathematical model for predicting the depth of embedment using the height of the retained soil, the standard penetration test values, and the bulk unit weight of the soils encountered for 261 pile data sets was introduced using an artificial neural network approach. The coefficient of determination equals to 0.99 for the tested the data reveal that the depth of embedment was accurate against those achieved in Zakho interchange. The importance and parametric studies obtained show that the major parameter which affects the depth of embedment was the height of the retained soil whereas the effect of other parameters is relatively less.

Design, Construction and Uncertainties of a Deep Excavation Adjacent to the High-Rise Building

In present infrastructure development, deeper basements are provided to satisfy parking scarcity. Safety and economy decide the system of shoring to go deeper below the ground level. This paper provides the design and construction of a deep excavation for an office building located at Bengaluru. Finite element model developed through PLAXIS 2D software is used for designing the shoring system in the present case study. The design and construction of two different deep excavation schemes are discussed in this paper, they are proposed based on the soil profile, constraint of space, presence of adjacent structures and service lines. Along the excavation line at some locations, existing buildings were located in very close proximity leading to lack of space for providing required slope for stabilising with driven nails, so in order to keep the excavation sides stable in those locations contiguous pile with soil/rock anchors was proposed. This deep excavation was of particular interest because of the uncertainties faced during construction which lead to failure of almost 20 m deep slope adjacent to existing high-rise building. The existing adjacent high-rise building was fully functional at the time of deep excavation. Potential large deformation of the adjacent high-rise building caused due to slope failure was one of the main concerns immediately after the failure. The immediate remedial measures taken to safeguard the footing of the existing high-rise building has also been included in this paper. The measure includes like immediate backfilling followed by grouted nail proposed along the failure surface.

Deformation Characteristics of Retaining Structures and Nearby Buildings for Different Propped Retaining Walls in Soft Soil

Abstract This article reports the field performance of deep excavations of two subway station cases, including the lateral wall deflection behavior and settlement trends of the surrounding soil and nearby buildings. The retaining structures employed in these cases were contiguous pile walls (CPW), soil-mixing walls, and diaphragm walls (DW), all of which were embedded in soft clay. The measured wall deflection profiles exhibited typical bulging behavior at the end of the excavation. The ratios of the measured maximum wall deflection to the excavation depth were found to be similar for all three types of retaining wall. Furthermore, the maximum and minimum corner effects on the wall deflection development were obtained for the DW and CPW, respectively. The measured ground surface settlement increased linearly with increased maximum lateral wall deflection, while the settlement magnitude became extraordinarily large because of the presence of sludgy soil. A concave pattern was proposed for the surface settlement profiles for all three types of retaining wall. The building settlement was quantified, with the value lying between those of the surface settlement and soil settlement at 10-m depth. The soil displacement field induced changes in the side and end resistance behaviors of the loaded piles, along with additional settlement of pile-foundation buildings. In addition, the pile-foundation building settlement was influenced by the corner effect. These research results will enhance our understanding of the deformation characteristics of the retaining structure and nearby buildings. Meanwhile, the findings will provide guidance for the optimal design of the retaining structure in soft soil.

L’habitat Néolithique final de Beau Phare à Aiguebelette-le-Lac (Savoie) : nouvelles approches méthodologiques de la planimétrie d’un village littoral de l’arc alpin

L’habitat Néolithique final de Beau Phare à Aiguebelette-le-Lac (Savoie) : nouvelles approches méthodologiques de la planimétrie d’un village littoral de l’arc alpin

An engineering solution for a hillside project in Hong Kong

With the increasing land demand in Hong Kong, some developments encroach into existing hill slopes or even natural terrain, which presents a big challenge to geotechnical engineers to produce cost-effective site formation and foundation designs. This paper showcases an example of a large-scale site formation work with the use of a 3 m dia. permanent contiguous bored pile wall supported by permanent tie-backs to facilitate a 38 m deep excavation against a sloping terrain. With the use of the tie-back system, the movement of the adjacent ground was substantially reduced. This paper discusses the exceptional constraints and the construction challenges in this project, which include the limited site access, the difficult terrain with lack of suitable working platforms or flat grounds within the site, exposure to natural terrain hazards and the highly unbalanced excavation across the site. These constraints result in extensive temporary steel and earth platforms for facilitating the foundation construction and the excavation and lateral support works with a complex construction sequence. In addition, the findings of the back-analyses are presented to compare the predicted and the actual ground deformations using different soil models.

A study on the reliability analysis of a deep excavation supported with anchored pile walls

AbstractThis paper presents a study performed to examine the applicability and convenience of the random set theory in combination with the finite element method (RS‐FEM), considering a case of a deep excavation. A case history of a 15 m deep multi‐anchored contiguous pile wall in clay is considered. Existing buildings around the excavation have necessitated a careful evaluation on the deformations and the reliability of the system. However, due to the existence of limited investigations, the soil parameters had to be estimated combining the results of these investigations with previous experience and expertness under similar conditions. Plane strain numerical analyses have been performed in order to predict the wall behavior. The parameters in the random set model have been chosen based on the sensitivity analyses. Most probable boundaries of the wall horizontal deformations have been compared with inclinometer readings. As suggested by previous case histories, wall deformations have been observed to fall within the lower third of the range predicted by RS‐FEM.

Cantilever Contiguous Pile Wall for Supporting Excavation in Clay

In urban areas, there are many situations where basement of new constructions or underground utilities are proposed to be constructed adjacent to old buildings. Of greatest concern are buildings with shallow foundations that do not extend below the zone of influence of the adjacent excavation. For deep excavation, the presence of a cantilever stage at the beginning of a construction sequence can often lead to excessive movements. Therefore over-excavation can also be a primary cause of excessive movements. In the present study, shallow excavation was considered. Three Dimensional Finite Element (3D FE) study was carried out in the present study. A cantilever contiguous pile wall was selected because it is common and relatively economic to be used in cohesive soil. Parametric study were performed considering excavation depth, pile embedded depth, and wall stiffness. Some design recommendations were given to provide a safe supporting system in clay.