Bearing Capacity Of Single Pile Research Articles

Comparison and analysis of conversion methods for self-balancing test of pile bearing capacity

The principle and method of self-balancing test are introduced briefly. In this article, through comparison of common Q-S curve of equivalent transformation to transform from the balance of the measured load-displacement curve for the traditional method of load - displacement curve, puts forward the advantages and disadvantages of each, through the three bored piles in static load test of pile reaction from balance to detect vertical compressive ultimate bearing capacity of single pile is in line with the requirements and compare the load-displacement curve after conversion. Some problems of the self-balancing method in engineering are pointed out, which is of certain reference value to the popularization and application of the self-balancing test of pile bearing capacity.

Bearing capacity assessment of bored piles equipped with expander body systems using the mechanics of unsaturated soils

Bearing capacity of single piles are occasionally predicted using the renowned theoretical methods (α and β methods). These methods are based on laboratory tests, which can be time-consuming, but also applicable in foundation engineering practice for unsaturated soils. Full-scale pile load tests were carried out on bored piles equipped with Expander Body Systems in the Federal District of Brazil, known for its unsaturated, collapsible and porous soil. This paper has the aim to assess the applicability of the β method, considering the contribution of soil matric suction, in order to estimate the bearing capacity of these piles subjected to uplift and compression loads in unsaturated soils. Based on the experimental results, it is indicated that the use of the β method considering the matric suction, can be a useful tool for bearing capacity estimation of bored piles equipped with Expander Body Systems in unsaturated soils.

Experimental Investigation of the Uplift and Lateral Bearing Capacity of Root Piles

The root pile, a new type of pile foundation with a variable cross-section, is introduced. The mechanism of root piles under uplift and lateral loading and the construction process are presented and discussed. The bearing capacity of root piles under uplift loading, lateral loading, and combined uplift and lateral loading was compared with that of conventional straight piles through field loading tests, which were performed on two straight piles and two root piles. The results indicate that the uplift and lateral bearing capacity of root piles is significantly greater than that of straight piles; the combined uplift and lateral loading has almost no influence on the uplift bearing capacity of single piles, but would weaken their lateral bearing capacity; the roots are engaged gradually from the top to the bottom under uplift loading; the resistance of the roots increased substantially because of the interaction between the soil and roots; however, the side friction of the pile shaft above the roots decreased because of this interaction. Increasing the burial depth of the roots could improve the performance of the roots for building applications.

A new type of PHC pile-sinking technology: Drilling with PHC Pipe Cased Pile and its development directions

Pile foundation has unique advantage in reducing the settlement of the upper structure and improving the foundation bearing capacity, while Drilling with PHC Pipe Cased Pile (DPC Pile) is a newly developed non-extruded soil PHC tubular pile which integrates drilling-pile sinking-dumping simultaneously to solve the pile sinking problem of large diameter (800 ∼ 1400mm) pipe pile. It solves the problem of pile sinking caused by large pile diameter or hard soil layer, breaks the situation that the pipe pile foundation can only be limited to small diameter and size, and broadens the applicable scope of engineering geology of pipe pile. It realizes the full rock-socketed of the pile tip (which can enter the middle and weak weathering stratum), improves the bearing capacity of single pile, and gives full play to the advantages of pipe pile material with higher strength. It has little damage to the pipe pile and little noise, being relatively environmentally friendly, as well as plays a major demonstration role in leading the new direction of the development of green, energy-saving and environmental protection pile foundation, conforming with the advanced development trend of upgrading traditional advantageous industries to high-tech manufacturing and construction technology with promising market.

Use of PDA Dynamic Test Results in Determining the Bearing Capacity of Single Pile in Marine Structures by Artificial Neural Networks

Use of PDA Dynamic Test Results in Determining the Bearing Capacity of Single Pile in Marine Structures by Artificial Neural Networks

Ultimate Load Tests on Bearing Behavior of Large‐Diameter Bored Piles in Weathered Rock Foundation

Based on the vertical compressive static load test and pile mechanics test of three large diameter bored piles (one of the test piles was treated with postgrouting) in granite gneisses foundation, the bearing capacity, deformation characteristics, and influencing factors of the single pile under the limit state are analyzed and compared with the recommended values of survey report and the recommended values of current codes. By comparing the measured and theoretical values of pile axial force, the bearing capacity of cast‐in‐place pile under normal and limit conditions is analyzed. The experimental results show that the Q-s curve of large‐diameter rock‐socketed mud wall retaining bored pile with a length‐diameter ratio of 25–33 and rock‐socketed depth of 5–8 d shows a rapid growth. After grouting treatment, the ultimate compressive bearing capacity of single pile is improved, the maximum settlement is reduced by 6.6%, the rebound rate is reduced by 11.1%, and the settlement effect of controlling pile top is not significant. The bearing capacity and deformation characteristics of the three test piles are less affected by length‐diameter ratio and rock‐socketed depth. For postgrouting piles, the ratio of frictional resistance of rock‐socketed segment and the ratio of pile lateral resistance are less affected by length‐diameter ratio and rock‐socketed depth, while, for postgrouting piles, the ratio of pile lateral resistance is more affected by rock‐socketed depth. The pile end resistance ratio of the three test piles is significantly affected by the rock‐socketed depth, whether or not the pile side postgrouting treatment is carried out.

Determination of Bearing Capacity of Single Pile based on Seismic Piezocone Penetration Tests

Based on the similar characteristics of installation about the penetrometer of seismic piezocone penetration tests(SCPTu) and the single pile, a theoretical relationship between ultimate bearing capacity of single pile, time-effect of shaft bearing capacity of single pile, excess pore water pressure around the pile during pile driven and the data measured from SCPTu is developed according to the cavity expanded theory, the Terzaghi one-dimensional consolidation theory and effective stress theory. The result of field test in KunShan and the calculated result which used the theoretical relationship mentioned above are compared. The results indicate that the analytical solutions agree well with the in-situ tests, which show that the applications of seismic piezocone penetration tests have wide range in the design of pile foundation.

软岩嵌岩桩承载力的计算与试验对比分析

在福建沿海地区许多重要建筑物都是以软岩作为其桩基持力层，本文依托某高层建筑的工程情况，对该工程中具有代表性的6根软岩嵌岩桩，按照JGJ94-2008《建筑桩基技术规范》、GB5007-2011《建筑地基基础设计规范》来计算其单桩竖向承载力，并进行了现场荷载试验，对计算和试验结果进行对比分析，得出了有意义的结论，为同类工程提供参考。 Many important buildings in coastal areas of Fujian are soft rock as its pile foundation bearing layer. Based on engineering geological conditions of a tall building, for six typical rock-socketed piles in soft rock area, according to Technical Code for Building Pile Foundation (JGJ94-2008) and Design Code for Building Foundation (GB5007-2011), this paper calculates vertical bearing capacity of single pile, and the load tests are carried out. The calculation and test results are compared and analyzed, and some useful conclusions are drawn. These conclusions will provide references for similar projects.

Assessment of CPTU and static load test methods for predicting ultimate bearing capacity of pile

ABSTRACTFor the static pressure pile, the most important is to determine the standard value of ultimate bearing capacity of single pile. At present, the bearing capacity of pile foundation is usually determined by the cone penetration test (CPT) test. The empirical formula was used in practice, but the effect of excess pore water pressure generated in the penetration on the measured cone-tip resistance and side friction is neglected. In this study, based on the field test results at Fengyu playground at Yancheng Institute of Technology by CPT and CPTU methods, the bearing capacity of pile was predicted by the standardized methods, the LCPC (France method) and CPTU direct prediction methods. The prediction was also compared with the results by the static load test method. The prediction accuracy of the CPTU method was then discussed as well. The results reveal that the accuracy of the CPTU method was the highest, which was consistent with the results obtained by the static load test method. It is the best method and worthy of being applied for predicting bearing capacity of piles in engineering applications.

Analysis on Pore-Forming Pouring Pile Construction Technology of House Building Project

Compared with the in-place pile, the pore-forming pouring pile is more simple and convenient, with a wider range of construction. In the actual construction process, it is able to pass through complex bottom layer and water layer underground without very high requirements in equipment. The actual bearing capacity of single pile is very strong, so that it can be better to adapt to the actual needs of different scales or the different geological conditions in building. And it has been promoted and used greatly in building construction work [1]. This paper introduces the concept of the pore-forming pouring pile technology, analyzes the pore-forming construction technology and the pile construction technology, then talks about prevention problems of the pore-forming pouring pile construction in House Building Project, at last draws a conclusion that the pore-forming pouring pile technology is the most basic construction technology and is the most effective and convenient way of construction.

Finite Element Analysis of the Influence About the Space Between Bearing Expanded-Plate to the Bearing Capacity of Single Pile of the MEEP Pile

In this paper, by ANSYS software it is built that a computer simulation analyzing model according to the finite element method, which is analyzed that the failure mechanism of the main pile and the soil around the bearing expanded-plate of the Multi-Expanded-plates pile(the MEEP pile), it is qualitatively determined that the space between the bearing expanded-plates affect the bearing capacity of the single pile of the MEEP pile, and of which the lower limiting value is put forward, in order to provide the theoretical support to the actual design of the MEEP pile

The Research on the Affect of Collapse State and Bearing Capacity of the Soil Layer Properties Adjacent to the Bearing Plate of the Multi-Extruded-Expanded-Plates Pile

This paper introduces the research status and analysis of the Multi-Extruded-Expanded-Plates pile (the MEEP pile) at home and abroad, by studying when the plate of pile embedded in different characteristics soil layer, the thickness, physical properties of upper and lower soil layer adjacent to the soil with plate cause the influence on soil break and bearing capacity of the soil layer with plate, analyzing the work together with pile and soil in different soil layer, providing a theoretical basis to improve the calculation formula of bearing capacity of single pile, ensuring the rationality and reliability of the design of the MEEP pile.

Analyzing on Bearing Performance Influence Factors of Step Cross-Section Pipe Pile

In order to improve the bearing behavior and the bearing capacity of single pipe pile, the technology of step cross-section pipe-pile is proposed.Based on FLAC3D, the finite difference model of the pile-soil interaction established,bearing behaviors of step cross-section pipe pile and unimate cross-section pipe pile is studied comparatively and bearing performance influence factors of step cross-section pipe pile is discussed.The results show that the bearing capacity of step cross-section pipe pile is much higher than unimate cross-section pipe pile in the same geological conditions and material dosage. For layered foundation, the bearing capacity of single pile may be improved by setting variable cross-section pile joint in relatively hard soil. But the depth of joint embedded in hard soil has little influence on bearing capacity of single pile.There is an obvious effect on increasing capacity of single pile by improving soil properties of soft soil surrounding pile.

A Study of PHC Pipe Pile Vertical Ultimate Bearing Capacity Calcula-tion Method and its Numerical Simulation Analysis

According to the PHC pipe pile design of Xinwan Plaza, Huaiyuan, Anhui and pile test results of static sounding method and experience method using the ultimate bearing capacity of single pile are calculated, considering the effect of soil plug the influence of vertical ultimate bearing capacity of single pile, and the formula for calculating the lateral resistance and end resistance, static sounding method and the correction formula to calculate the bearing capacity calculated results was coincident with the results of test pile. Combining with the project of Xinwan Plaza, Huaiyuan, Anhui, through the static load test, a study of the load transfer mechanism of PHC pipe pile, analyzes the vertical load, the change rule of the settlement of pile body and pile and the use of finite difference software FLAC3D simulation of the PHC pipe pile static load test, the simulation results agreed with the measured load-settlement curve.

The Research on the Ultimate Bearing Capacity of Soil around the Push-Extend Multi-under-Reamed Pile at Sliding Failure State

In the paper, the existing unreasonable place of the calculation formula of the bearing capacity of single pile is put forward. Through analyzing the failure mechanism of the soil up and under the Multi-under-reamed, the method for calculating the ultimate bearing capacity of soil around the PEMUR pile can be determined by using the slide-line theory, and the calculation formula of the bearing capacity of single pile of the PEMUR pile is further revised and perfected.

Study on Optimization of Design Parameters for Composite Foundation with Cement-Fly Ash-Gravel Piles

Based on theoretical analysis and experimental result, the principle as well as the interaction between pile and soil, the design parameters of composite foundation with cement-fly ash-gravel piles (CFG piles for short) are optimized, which are pile length, pile diameter, pile spacing, pile strength and thickness of cushion layer, in order to put forward the reasonable design parameters for reaching economic and reasonable target. Through the optimized analysis, it is put forward that bearing stratum of pile tip should select a relatively better soil layer, the diameter of CFG pile is usually appropriately to select between 350mm and 500mm, it is usually appropriately to select larger pile spacing under the permissible range between 3d and 5d being ruled by standard, it is appropriately to enlarge the pile diameter to reduce the requirement of pile strength in high rise and super high rise building which requiring bearing capacity of single pile is high, and the thickness of cushion layer is appropriately to select between 0.4 and 0.6 times of the pile diameter.

Analysis of Diameter of the Bearing Push-Extend Reamed in the Size of the Influence of the PEMUR Pile Bearing Capacity of Single Pile

As the change of diameter of the bearing push-extend reamed in the size, failure pattern of soil mass around the PEMUR pile has changes. Based on the finite element method, simulated analysis has been conducted about normal stress and shear stress of soil around pile under different plate diameter size, which has qualitatively identified that the PEMUR pile bearing capacity of single pile has influence on disc diameter, application for this type of pile design provides a theoretical basis.

The Review on the Modified Exponential Model in the Fitting of Loading-Settlement Curves of Single Pile

According to optimized fitting analysis for measured data in static load test of 22 different types of single piles, a new modified exponential model was proposed by authors in this paper. In comparison between the hyperbolic model and the integrated exponential curve model, the correlativity coefficients R of the modified exponential model were over 0.996. The fitting effect of the model of proposed in this paper is better than that of other models above-mentioned. The deviations between fitting and measured data in static load test for single pile was small, especially, in the tail pasts of fitting curves, the mean deviations of 2 test pile given in the paper are 1.61% and 1.99% respectively. The modified exponential model can be better described Q-S curves of single piles. It can be used to better evaluate the ultimate bearing capacity of single piles.

Axial Force Analysis of the Single Pile Based on FLAC3D

Complex interaction mechanism of pile and soil, pile load transfer analysis is difficult. On the basis of analyzing the load transfer mechanism of the friction pile, using the FLAC3D analysis on the initial ground stress state of equilibrium , axial load under the action of pile axial force and displacement, got the ultimate load bearing capacity of single pile and the stress of the contact surface. Analysis results show that the load and displacement in a certain stage into a proportional relationship. Also shows that simulation is feasible and provide a reliable method for the analysis of pile groups.

The Discussion about Improving the Bearing Capacity of Single Pile for Bored Pile in Sandy and Silt Layer

The bored pile which have the unique advantage in having no noise, no shake, no upheaval, no sides way in the process of construction has became into one of the most widely used pile foundations in high heavy construction in Inner Mongolia region. Through an engineering project of bored piles in Inner Mongolia region, this article takes an analysis for bearing behavior of the bored piles in sandy and silt layer in this region. It also discusses the influence construction technology on pile-end ultimate resistance and the reasonable range of reduction factor of the ultimate resistance. When the soil layers structure is similar, it could improve bearing capacity of single pile for bored pile by utilizing the supporting layer and substratums optional regrouping. Utilize traditional single pile bearing capacity theory formula calculating and the static load test results it takes an analysis, finding out the approach of improving the bearing capacity of single pile for bored pile in sandy and silt layer. So we could find the optimization design for pile foundation bearing capacity of bored pile and thus promote the improvement in bored piles theory research and engineering application level in Inner Mongolia region and provide theory and engineering design experience.