Pile Settlement Research Articles

Load-Settlement Analysis of Axially Loaded Piles in Unsaturated Soils

Unsaturated soil covers a significant part of the world, and studying the behavior of deep foundations in this medium is an important step in increasing accuracy and economic efficiency in geotechnical studies. This paper presents an analytical solution to investigate the load-carrying characteristics of single piles embedded in unsaturated soils, accounting for the effect of groundwater level on the pile’s response. For this purpose, relationships for shear modulus and Poisson’s ratio for unsaturated soils were collected from the literature to consider their effects as key parameters on pile performance. A parametric study was conducted to evaluate the effect of soil moisture content on the behavior of the pile-soil system for different soil types, and the effect of pile slenderness on its load-settlement behavior was studied for varying soil moisture contents. The results indicate that the pile stiffness increases as the soil suction increases while below a critical slenderness value, hence increasing the pile load capacity. However, this improvement occurs within a limited range of soil suction that is narrower for coarse-grained soils. The pile settlement corresponding to soil failure was also evaluated by modifying the existing solutions for unsaturated soils. The developed solutions were verified against the predictions of published solutions as well as the results of finite element analysis and pile load tests. It was found that the system stiffness decreases by 50% when the water table rises from the pile toe level to the ground surface in the studied soil.

Experimental and Numerical Simulation Study of Water Infiltration Impact on Soil-Pile Interaction in Expansive Soil

A laboratory model of a single pile embedded in Nanyang expansive soil and subjected to water infiltration is applied in this study to examine the interaction between the expansive soil and pile foundation upon water infiltration. The soil matric suction decreases as a result of the rising soil-water content. The amount of soil ground heave reaches its peak of 10.7 mm after 200 hours of water infiltration. As matric suction decreases, pile shaft friction also declines, which causes more of the load at the pile head to be carried by the pile base resulting in more pile settlements. A new numerical simulation method is provided to simulate this issue by coupling the subsurface flow, soil deformation, and hygroscopic swelling to investigate the expansive soil-pile response upon water infiltration. From the numerical simulation model, hygroscopic strain arises as a result of elevated moisture levels resulting from the entry of water, and due to ground heave and the mobilization of lateral soil swelling, the shear stress at the interface between the soil and the pile gradually increases over time. It reaches its maximum value of 4420 Pa at upper depths around 200 hours after the infiltration. The comparison between the lab model testing data and the numerical model results demonstrates a good level of concurrence.

Study on the dynamic construction mechanics of side piles in metro station using the pile-beam-arch method

Based on the Tianhe East Station in Guangzhou Metro Line 11 engineering, this paper analyzes the formation mechanism of soil arching effect (SAE) of station by pile-beam-arch (PBA) method in the excavation process and studies the mechanics and deformation laws of side piles in different construction stages under different pile spacing conditions. The results show that the formation, development and destruction of SAE between piles are closely related to construction process. Both too large and too small pile spacings are not conducive to the development about SAE between piles; when it is located between them, the SAE between piles exerts greatly. In the form of composite lining system, supporting piles as well as SAE between piles play an effective role in supporting soil behind piles. The lateral deformation of pile body is most significant in the completion of buckle arch to the excavation of first soil layer, which is the critical construction phase to reduce lateral deformation of side pile. The axial forces of side pile increase gradually with the excavation of station, and the change is the most drastic at the excavation for first soil layer. The influence of pile spacing on vertical settlement and axial force of side piles is much greater than that of horizontal displacement and bending moment.

Predicting Load-Settlement Behaviour of Large Diameter Piles using Runge-Kutta numerical Method.

A numerical solution for predicting the axial load and corresponding settlement of large diameter piles is proposed based on the hyperbolic curve load transfer function in this paper. It is important to note that the most reliable approach to determine the axial load capacity of a pile is to use the P-S curve, which is usually obtained through an on-site load test. Performing a pile load test on a large diameter pile (pile diameters over 3m), requires a thousand tons of test load, which sometimes is unachievable. The load-settlement relationship or P-S curve of this type of pile can be determined by the Runge-Kutta numerical method for practical application especially for offshore piles. Comparison is made between the results obtained by this proposed numerical, the test data, analytical solution and pile load test data, and close agreement has been found thus verifying the accuracy of the proposed method. However, the rigid body displacement of the piles did not show any significant effect on the proposed numerical when compared to the analytical and onsite pile load test results. It is expected that the proposed numerical method can be used to predict the load and corresponding settlement of large diameter piles.

Numerical Analysis Study on the Influence of Shield Cutting Pile on the Settlement of Pile–Soil Composite Foundation

Based on the shield cutting pile–soil composite foundation project of Zhengzhou Metro Line 5, numerical analysis was employed to replicate the in situ experimental conditions on site. The study focused on investigating the impact of shield cutting piles on the settlement of pile–soil composite foundation and analyzing the sensitivity of shield construction parameters, face pressure (P), and grouting pressure (Q). Comparing the numerical analysis results of land surface subsidence with field in situ test monitoring results reveals a consistent pattern, validating the rationality of the numerical modeling method presented in this paper. The results demonstrate that the vertical displacement of the formation caused by shield cutting pile construction can be divided into settlement and uplift areas. The region with significant formation displacement settlement spans within 0.9D (5.4 m above the tunnel vault), whereas the area with pronounced formation displacement uplift ranges within 0.58D (3.5 m below the tunnel arch bottom). The influence of face pressure (P) on the bearing characteristics of the composite foundation primarily occurs during the prepile cutting stage, whereas the influence of grouting pressure (Q) on the bearing characteristics of the composite foundation mainly manifests after the shield tail separates from the residual pile of the composite foundation.

Prediction of pile settlement by using hybrid random forest models

Prediction of pile settlement by using hybrid random forest models

Prediction of pile settlement using hybrid support vector regressor

Prediction of pile settlement using hybrid support vector regressor

Soil Consolidation Analysis in the Context of Intermediate Foundation as a New Material Perspective in the Calibration of Numerical–Material Models

This paper presents the authors’ research results from an analysis of intermediate foundations as well as slab and pile foundations in the context of soil consolidation. Looking at soil as a building material that changes its properties over time is very important from the point of view of the safety of construction, implementation, and operation of building structures. In addition, soil can be parameterized in such a way as to accurately describe its possible behavior under service loading. Of great interest is the phenomenon of consolidation, which is based on the reduction of soil volume over time under constant loading. This study explores existing piles and replicates soil conditions to understand individual and grouped pile behavior in combined pile–raft foundations (CPRF). To assess pile settlement from primary and secondary consolidation phases, 13 field measurements on concrete columns in gyttja clay were conducted. Analyzing data from these tests allowed engineers to accurately calibrate a numerical model. This calibrated model was instrumental in designing high-rise buildings, ensuring stability and safety. This study emphasizes the importance of understanding soil behavior, particularly consolidation phenomena, in optimizing foundation design and construction practices.

Experimental Study on Post-Grouting Pile Vertical Bearing Performance Considering Different Grouting Methods and Parameters in Cohesive Soil

The selection of grouting methods and parameters significantly affects the improvement in the pile-bearing capacity of cast-in-place bored piles. This study proposes a comprehensive set of test methods for constructing model piles, performing grouting at the pile tip and pile side. A series of single-pile grouting and static load tests were conducted using these test methods. The results reveal that pile-side grouting is more effective in controlling pile settlement compared to tip grouting. Furthermore, tip-side-combined grouting exhibits superior reinforcement effects compared to the other two grouting methods. After grouting, a grout bubble is formed at the outlet, consisting of a compact diffusion zone internally and a split diffusion zone externally. Additionally, a vertical diffusion of grout occurs along the pile body, establishing a lateral friction resistance enhancement region. Within this region, the lateral friction resistance of the pile shows a negative correlation with the distance from the grouting outlet. The test results emphasize the significance of grouting volume and its impact on the bearing capacity, settlement control, lateral friction resistance, and grout bubble size in grouted piles, while the influence of variation in grouting pressure in a small range on bearing characteristics is not significantly apparent.

Three-dimensional Finite-element Analysis of the Influence of Tunneling on Pile Foundations

Advancing tunnel boring machine (TBM) during tunnel construction induces a surface settlement, affecting adjacent buildings and facilities. A three-dimensional finite-element model (Plaxis 3D) was used to simulate and analyze this process. A comparison between the numerical model and field measurements of the Greater Cairo Metro (Line 3) was made to validate the obtained results. A sensitivity analysis was conducted to determine how changes in some parameters, such as constitutive models, pile position relative to the tunnel axis and pile spacing, affect the results of the finite-element model. Three constitutive models: hardening soil small (HSS), hardening soil (HS) and the Mohr-Coulomb (MC) models, were used to evaluate the effect of the constitutive models on the results. From the numerical analysis, it is clear that the numerical results are in good agreement with field measurements. The results of the HSS model are more realistic and closer to field measurements than those of the HS and MC models. Furthermore, the effect of the tunnel construction on the settlement of adjacent piles is virtually null at a distance of 2 D (where D is the tunnel diameter). Finally, increasing the pile spacing decreases the effect of tunnel excavation on adjacent pile foundations. KEYWORDS: Tunneling, Numerical models, Constitutive models, Pile foundation, Pile spacing

Estimation of Screw Displacement Pile-Bearing Capacity Based on Drilling Resistances

Abstract This article presents an engineering, empirical method of estimating the bearing capacity and settlement characteristics Q-s of screw displacement piles and columns, based on soil resistance encountered during the drilling to form piles/columns in the ground. The method was developed on the basis of correlation analyses of the test results of 24 piles made during the “DPDT-Auger” research project (Krasiński et al., 2022a). In the proposed method, the load capacity of a screw displacement pile is estimated using two main parameters of auger screwing resistance: torque MT and the number of auger rotations per depth unit nR . The method applies to piles and columns made with a standard screw displacement pile (SDP) auger and with the proprietary, prototype DPDT (displacement pile drilling tool) aguer, patented in Poland (2020). Based on the estimated ultimate capacities of the pile shaft and base, an approximate method of predicting the pile settlement characteristics Q-s was also proposed, using the transfer function method. This article describes a correlation procedure of field test results together with their statistical analysis and presents a method of estimating the pile-bearing capacity based on correlation results. A calculation example is also provided. The conclusion looks at the useful practical applications that could be found for the proposed method.

Prediction of socketed pile settlement based on a hybrid form of multilayer perceptron via meta-heuristic algorithms

Prediction of socketed pile settlement based on a hybrid form of multilayer perceptron via meta-heuristic algorithms

Predicting the settlement of pile based on a hybrid form of the model by considering Least Square Support Vector Regression

Predicting the settlement of pile based on a hybrid form of the model by considering Least Square Support Vector Regression

Assessment of twin tunnelling induced settlement and load transfer mechanism of a single pile in dry sand

This study conducted both three-dimensional physical model tests and numerical back-analyses to examine the performance of a single pile subjected to twin tunnelling beneath the pile toe in dry sand. Moreover, numerical parametric analyses were carried out to assess the impact of working load level and tunnel volume loss on pile behaviour. The findings revealed that the first tunnelling induced a 1.9% dp (pile diameter) settlement in the pile when the pile toe was 0.5 D (tunnel diameter) above the twin tunnels, which had a 1.0% volume loss. The settlement was accompanied by an upward load transfer mechanism. The second tunnelling had a reduced impact and induced only 76% of the settlement caused by the first tunnelling. The study also showed that tunnelling-induced shearing behaviours weakened beneath the pile toe with a decrease in working load, resulting in reduced pile head settlement. Moreover, the computed pile settlement increased by 178% when the tunnel volume loss increased from 0.5% to 2%. The findings of this study offer valuable data for the validation and calibration of numerical models. In addition, the outcome from this study provides useful insights into the prediction of the pile-soil-tunnel interaction when subjected to twin tunnelling.

Research on the bearing behavior of single pile in self-weight collapsible loess areas.

The negative skin frictional caused by loess collapse will decrease the bearing capacity of single pile, which is essential to the design of pile foundations in loess areas. In this study, a method for estimating the subsidence of soil layer at any depth is firstly proposed based on the total self-weight collapse value. Secondly, a new load transfer constitutive model for pile-soil interface is developed, which considers the nonlinear stress-strain relationship and the ultimate shear strength of soil. Then, a load transfer calculation model for pile foundation is established, which can calculate the pile axial force, the pile skin frictional, neutral point position and the settlement of a single pile. The calculation results are compared with the test data that obtained from a pile foundation on-site immersion test and the effectiveness of the calculation method is verified well. This calculation method may be useful for designing pile foundations in collapsible loess regions.

Model test on thermo-mechanical properties of static drill rooted energy pile under long-term temperature cycles

Static drill rooted (SDR) pile emerges as a composite of a prefabricated pile and cemented soil. SDR pile technology was introduced into the energy pile design due to its high load-bearing capacity, excellent heat transfer performance and favorable stability. Indoor model tests were established to investigate the thermo-mechanical behavior of an SDR energy pile under long-term temperature cycles. It was found that the studied pile had better heat transfer performance and bearing capacity (50%) than the ordinary pile. After twenty long-term temperature cycles, Additional tensile and compressive stress were observed in the pile. The additional thermal stress in the pile initially increased and then decreased with the increasing depth of the pile. The stress fluctuation would not damage the pile material since it was maintained within the design value of concrete strength. The side friction of the pile gradually increased with the increasing cycle numbers. The cumulative settlement of the SDR energy pile was induced by temperature cycles and reached −0.155 mm (0.18% D) after 20 cycles, less than the ordinary pile. The first two cycles accounted for 53% of the total cumulative settlement, and cooling was the main factor causing pile top settlement. The ultimate bearing capacity of the SDR energy pile was decreased by 9% after 20 cycles. The investigation of the long-term thermo-mechanical behavior of the SDR energy pile provides a theoretical basis for its practical application. SDR energy piles are significant for the efficient use of shallow geothermal energy.

Effects of excavation and construction sequence on behavior of existing pile groups

In congested urban areas, new structures are regularly constructed next to high-rise buildings. At different stages of excavation for the new structures, settlement and tilting of the adjacent piled buildings may be occurred. Thus, attention here will be focused on the interaction behavior between deep excavation and adjacent piled foundations. Accurate prediction of soil movement and pile response plays an important role in preventing damages to adjacent buildings. Finite-element models are employed to compute the pile group responses. The parametric study has been performed by varying pile group configurations, center-to-center pile spacing, and new building load. Two, four, and six capped head pile groups next to excavation sites have been examined. In this paper, discussion centers on settlement and tilting of the pile groups nearby an excavation in fully saturated sand. The influence of pile group configuration and new building loads are systematically investigated. New building can be constructed in the excavated area after completion of the excavation. The effect of new building construction sequences is also investigated. Results provide confirmatory evidence that, excavation depth has the most significant effect on pile settlement and pile cap tilting. High pile cap tilting and small pile group settlement are apparent in case of two piles near the excavation. For the four pile group, the induced tilting of pile cap decreases as spacing between the piles increases. Due to construction of the new building, the settlement is exacerbated but the tilting is moderated.

Support Vector Machine to Predict the Pile Settlement using Novel Optimization Algorithm

Support Vector Machine to Predict the Pile Settlement using Novel Optimization Algorithm

Analisis Daya Dukung Fondasi Bored Pile Pada Rumah Sakit Sultan Imanuddin Pangkalan Bun

This study intended to analyze the bearing capacity of single bored pile, the bearing capacity of the bored pile group, the load carried, the safety factor, and the settlement that occurs. The first calculation method is Schmertmann and Nottingham method, and the second calculation method is Meyerhof method. Based on the calculation of the bearing capacity of a single bored pile using the Schmertmann and Nottingham method obtained a value Qu = 49005,88 kN, while the Meyerhof method obtained a value Qu = 1633.71 kN. The calculation results for bearing capacity of the pile group using the Schmertmann and Nottingham method obtained a value Qg = 164169,70 kN and the Meyerhof method obtained a value Qg = 5472.93 kN. The results of the load carried by the bored pile group using Schmertmann and Nottingham method is Qi = 353.98 kN ≤ Qg = 164169.70 kN which means it’s still within safe limits. Using the Meyerhof method is Qi = 353.98 kN ≤ Qg = 5472.93 kN which means it is still within safe limits. The safety factor using the Schmertmann and Nottingham method obtained SF = 463.78 and using the Meyerhof method obtained SF = 15.46 which means it is very safe. Total settlement of a single bored pile is S = 0.0142 m ≤ 0.04 m which means it is safe. And the settlement of the bored pile group is Sg = 0.03 m ≤ 0.08 m which also means it is safe

Investigation on thermo-mechanical response of energy piles in saturated clay

In recent years, energy piles have been widely used in the collection of shallow geothermal energy. However, the engineering characteristics of the soil and the mechanical behaviour of the pile are affected by temperature, particularly in clay. To explore the influence of heating–cooling cycles on the thermo-mechanical response of an energy pile in saturated clay, a laboratory model test was designed. The energy pile in saturated clay was subjected to ten heating–cooling cycles. A fibre Bragg grating (FBG) system was adopted to monitor the pile strain. Meanwhile, pile and soil temperature, pore water pressure and pile top displacement data were collected using a dynamic acquisition instrument. The results show that FBG sensors can achieve good results in measuring the axial strain of a pile. The distribution and transmission of thermally induced axial force and stress are affected by soil properties and pile constraints. Temperature cycling will lead to the thermal consolidation of saturated clay, improving the bearing performance of energy piles, and to an irreversible settlement of the energy pile.