Evaluating the Bearing Capacity of a Soil Layer Overlying Rigid Substratum Using a Modified Failure Mechanism Based on Limit State Analysis

2013 ◽  
Vol 353-356 ◽  
pp. 806-814
Author(s):  
Reza Afshar-Mazandaran ◽  
Hadi Khabbaz
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Limit State ◽  
Soil Layer ◽  
Finite Depth ◽  
Bound State ◽  
Shallow Foundations ◽  
Collapse Mechanism ◽  
Parametric Studies ◽  
Spiral Surface

The bearing capacity of shallow foundations resting on a soil layer with a finite depth over bedrock has been studied for years by many investigators. Farzaneh et al (2010) introduced a rigorous bearing capacity analysis based on the upper bound state theorem, using a log-spiral surface algorithm. This paper presents a thorough evaluation of this collapse mechanism and subsequently, a modified failure mechanism is introduced. The collapse mechanism consists of rigid blocks under combined rotational and transitional movements. The effects of the loading parameters on bearing capacity results are then discussed. The findings of this study are compared with the original limit state mechanism as well as previously published solutions, emphasising the accuracy and efficiency of the modified mechanisms. Furthermore, parametric studies are carried out to evaluate the ultimate bearing capacity of shallow foundations resting on a restricted soil, layer using the proposed mechanism. Design tables are finally presented for practical use in geotechnical engineering.

scholarly journals Reliability analysis of an end-bearing pile with account for friction forces on the pile surface

2020 ◽  
pp. 2-2
Author(s):  
Vladimir S. Utkin
Keyword(s):  
Bearing Capacity ◽  
Reliability Analysis ◽  
Limit State ◽  
Soil Layer ◽  
Material Behavior ◽  
Performance Criteria ◽  
Soil Behavior ◽  
Foundation Soil ◽  
Friction Forces ◽  
End Bearing Pile

Introduction. The behavior of end-bearing piles in the foundation soil and the methodology for their reliability analysis, treated as operational safety measures applicable to a separate bearing element of a pile foundation, need clarification and further development. The weakness of the established reliability analysis methodology, focused on the bearing capacity of the foundation soil, is its failure to take account of each case of the soil behavior above rock or low compressibility soils pursuant to Construction rules and regulations 24.13330.2011. Taking account of the bearing capacity of this soil layer in respect of the load accommodation by an end-bearing pile (taking account of the pile weight) may improve its reliability by the criterion of the bearing capacity in combination with the soil behavior below the bottom tip of a pile. Nizhne-Suyanskiy Waterworks Facility had the mission to solve water household, energy and socio-economic problems. Materials and methods. The author analyzed piles made of any applicable materials; their reliability analysis methods are based on the possibility theory due to the limited amount of statistical information on controllable parameters to be entered into the limit state design model to verify the bearing capacity of the foundation soil. Results. The author presents the design formula to identify the parameters ensuring reliable failure-free behavior of an end-bearing pile in the foundation soil and in respect of the soil bearing capacity. The pile reliability analysis performed in respect of its bearing capacity (and focused on the strength of the pile material) is provided in the references section. The author uses two performance criteria to analyze the reliability of an end-bearing pile, given that an end-bearing pile is analyzed as a consistent mechanical system in terms of the reliability theory. Conclusions. The author has developed a methodology used to analyze the reliability of end-bearing piles. It is focused on the bearing capacity of the foundation soil below the bottom tip of a pile and along its length with a view to the quantitative assessment of its safe performance at the stage of design of a facility that has a piled footing; the groundwork has been laid for further research into the behavior of end-bearing piles and for the development of design regulations applicable to various types of piles that may differ in material, behavior, sinking techniques, etc.

scholarly journals Analysis of Soil Characteristics Affecting Failure Behavior and Bearing Capacity of the Concrete Expanded-Plates Pile

2015 ◽  
Vol 9 (1) ◽  
pp. 188-191 ◽  
Author(s):  
Yongmei Qian ◽  
Dehao Ren ◽  
Ruozhu Wang
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Soil Layer ◽  
Soil Characteristics ◽  
Failure Behavior ◽  
Research Results ◽  
Bearing Plate ◽  
Soil Failure ◽  
Study Results ◽  
Different Characteristics

By analyzing the present research results on the concrete expanded-plates pile, the article presents further preliminary studies of their influence on the bearing capacity and failure behavior when the bearing plate is put adjacent to different characteristics of soil and thickness of soil layer. The pile calculation mode for ultimate compression and uplift bearing capacity of the soil failure mechanism of the concrete expanded-plates pile under different conditions is also improved. The study results ensure the rationality and reliability of the design and the applicability of this type of pile in the actual project.

Influence of failure mechanism on seismic bearing capacity factors for shallow foundations near slopes

Géotechnique ◽  
2021 ◽  
pp. 1-14 ◽  
Author(s):  
Shangchuan Yang ◽  
Ben Leshchinsky ◽  
Kai Cui ◽  
Fei Zhang ◽  
Yufeng Gao
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Shallow Foundations ◽  
Seismic Bearing Capacity

Three-dimensional upper-bound analysis for ultimate bearing capacity of laterally loaded rigid pile in undrained clay

2015 ◽  
Vol 52 (11) ◽  
pp. 1775-1790 ◽  
Author(s):  
Jian Yu ◽  
Maosong Huang ◽  
Chenrong Zhang
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Plane Strain ◽  
Upper Bound ◽  
Three Dimensional ◽  
Soil Conditions ◽  
Soil Parameters ◽  
Collapse Mechanism ◽  
Layered Soils ◽  
Rigid Plastic

A new three-dimensional upper-bound combined failure mechanism is presented to analyze the lateral ultimate capacity of rigid piles embedded in various soil conditions, involving homogeneous soils, layered soils, and Gibson soils. The wedge curved failure surface function composed by rotating the Newton interpolation polynomial is adopted near the ground surface, and a plane strain collapse mechanism is employed at depth. Furthermore, the energy dissipation of the transition interface is introduced to keep a kinematically admissible velocity field between the wedge and the plane strain mechanism. An empirical equation is then proposed based on the upper-bound solutions for the homogeneous soils, and extended to the layered soils and Gibson soils. Meanwhile, the three-dimensional arbitrary Lagrangian–Eulerian (ALE) analysis is employed to investigate the distribution of limiting pressures along the pile shaft for different soil parameters. It is found that the upper-bound solutions based on the rigid-plastic assumption only exhibits a good agreement with the finite element (FE) results for a very high soil rigidity index of 10 000, due to a Possion’s ratio of approximate but less than 0.5 in such a typical undrained FE analysis. For such a Possion’s ratio, an inevitably slight elastic volumetric change induces the unexpected cavity flow at the deep section of the pile. It leads to the soil rigidity affecting the profile distribution of the bearing capacity, although it is not true for a real undrained analysis. Finally, a centrifuge test is analyzed by the upper-bound method to further testify the rationality of the new failure mechanism.

scholarly journals Ultimate seismic bearing capacities and failure mechanisms for strip footings placed adjacent to slopes

2019 ◽  
Vol 56 (11) ◽  
pp. 1729-1735 ◽  
Author(s):  
Haizuo Zhou ◽  
Gang Zheng ◽  
Xinyu Yang ◽  
Tao Li ◽  
Pengbo Yang
Keyword(s):  
Soil Properties ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Limit State ◽  
Seismic Loading ◽  
Relative Increase ◽  
Superposition Method ◽  
Seismic Bearing Capacity ◽  
Strip Footings ◽  
Underlying Soil

Assessment of the ultimate bearing capacity of foundations adjacent to slopes is complex as it is highly dependent on the slope geometry and soil properties. Seismic loading may impact both the critical failure mechanism and its associated bearing capacity. The existing approaches for analyzing the seismic bearing capacity of footings near slopes typically employ coefficients developed to fit the conventions of Terzaghi’s bearing capacity equation, herein referred to as the “superposition method.” In this study, a rigorous assessment of the seismic bearing capacity is performed using an upper-bound limit state plasticity framework known as discontinuity layout optimization (DLO), which makes few prior assumptions concerning the failure geometry. Results show that soil properties, slope configuration, and pseudostatic seismic loading all influence the realized failure mechanism and associated bearing capacity. The use of bearing capacity coefficients that fit within the conventional superposition method may underestimate limit loads when the underlying soil provides a relative increase in resistance, but may greatly overestimate bearing capacity when the self-weight of the soil is destabilizing in nature. A set of design charts using direct computational methods for a variety of geometric, geotechnical, and seismic conditions is provided.

scholarly journals The influence of the stratum structure of the pipe pile sliding pile of the offshore platform

2021 ◽  
pp. 6
Author(s):  
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Soft Soil ◽  
Limit State ◽  
Soil Layer ◽  
Measurement Data ◽  
Friction Resistance ◽  
Side Friction ◽  
The Impact ◽  
Bearing Layer

This article has carried on the theoretical analysis to the generation mechanism of the sliding pile phenomenon. A certain prediction was made on the causes of slipping piles and their influencing factors. At the same time, it is based on the collected field measurement data, an engineering example is selected to briefly analyze the changes in the bearing capacity of the pile foundation after the sliding pile occurs. It is found that the influence of the sliding pile on the bearing capacity of the pile foundation is mainly the influence on the side friction resistance of the pile, and the reduction of the soil resistance is also mainly due to the reduction of the side friction resistance of the pile. Finally, using ABAQUS finite element analysis software, a numerical simulation analysis was carried out on the changes of the stratum structure, the analysis results show that the position change of the soft soil layer has a certain influence on the bearing capacity of the pile, but it does not change the settlement of the pile top under the limit state; The greater the strength of the supporting layer, the greater the bearing capacity and the greater the displacement when reaching the limit state; The length of the slipped pile does not affect the bearing capacity of the pile foundation, and the farther the slipping occurs from the bearing layer, the smaller the impact on the bearing capacity of the pile foundation. Therefore, in the actual project, attention should be paid to the selection of the bearing layer and the soft soil layer close to the bearing layer should be removed to reduce the impact of the slipping pile on the bearing capacity of the pile foundation and ensure that the bearing capacity of the pile foundation meets the design requirements.

scholarly journals DESIGN OF REINFORCEMENT OF FOUNDATIONS OF RECONSTRUCTED, RESTORED BUILDINGS USING PILES

2020 ◽  
Vol 11 (4) ◽  
pp. 33-45
Author(s):  
A. I Polishchuk ◽  
I. V Semyonov
Keyword(s):  
Bearing Capacity ◽  
Soil Layer ◽  
Shallow Foundations ◽  
Soil Conditions ◽  
Building Structures ◽  
Building Structure ◽  
Construction Site ◽  
Structural Elements ◽  
Before And After ◽  
Design Loads

The procedure for designing reinforcement of shallow foundations of reconstructed, restored buildings using piles (injection, bore injection, composite pressed, screw, etc.) is considered. At the first stage of the design, the constructive solution of the existing foundations, the structural diagram of the building (structure), as well as the loads transferred to the building structures before and after the reconstruction (restoration) of the building are established. An assessment of the soil conditions of the construction site of the building being reconstructed is carried out; a bearing soil layer is identified for deepening the lower ends of the piles. Based on the data obtained, the loading of the base of the foundations of the reconstructed (restored) building is assessed and the need for their strengthening (or their further operation without reinforcement) is established. In the event that strengthening of the building foundations is required, the method of transferring the additional load to the piles is chosen. After that, the bearing capacity of the piles and the design loads allowed on the piles are substantiated. The design of foundations is carried out taking into account their reinforcement with piles, as well as verification calculations of the base of reinforced foundations (combined) for the first and second groups of limiting states (for bearing capacity and deformations). In accordance with the regulatory documents, strength calculations of the main structural elements of foundations are performed, which are necessary to ensure their full-fledged operation, taking into account reinforcement. At the final stage, working documentation is developed to strengthen the foundations of the reconstructed, restored building (structure). The presented algorithm for the design of strengthening the foundations of reconstructed, restored buildings using piles allows to correctly and consistently organize the work of specialists.

scholarly journals Bearing strength calculation of end-bearing piles under recognition of cohesive friction on the pile surface

2019 ◽  
pp. 1-1 ◽  
Author(s):  
Vladimir Utkin
Keyword(s):  
Bearing Capacity ◽  
Limit State ◽  
Soil Layer ◽  
Design Stage ◽  
Material Strength ◽  
Soil Base ◽  
Foundation Soil ◽  
Bearing Strength ◽  
Base Soil ◽  
End Bearing Pile

Introduction. It is a drawback of the existing end-bearing pile design method for soil base bearing capacity that the latter is not taken into account in the assessment of the foundation soil action above the rock or a low-compression soil layer in all cases in accordance with the Building Code 24.13330.2011. However, taking into account the bearing capacity of this layer of the soil base in the load accommodation by the end-bearing pile (under recognition of the pile weight) could increase its calculated bearing capacity by the respective value of the soil base bearing capacity in combination with the soil support action under the pile’s lower end. The objective of the research is improving the trustworthiness of the calculation result of the bearing strength of end-bearing piles in the soil base, identifying the pile’s bearing strength reserve by taking in account the additional soil base bearing capacity due to the cohesive friction on the side surface of the pile. Materials and methods. The object of the research are piles of any applicable materials. The methods of calculation of the end-bearing piles are based on on cohesive friction values and their distribution along the pile length in a limit state calculation model in terms of the soil base bearing capacity. Results. The paper presents the equation of the ultimate compression load of the end-bearing pile in terms of the foundation base soil bearing capacity and the formula for the base soil bearing capacity reserve factor of the pile. The calculation of the pile bearing strength in terms of the material strength is referenced in the bibliography. Conclusions. A calculation method of end-bearing piles bearing strength was developed based both on the bearing capacity of soil base under the pile lower end and the additional soil bearing capacity along the flanks of the pile. The method could be applied also for calculations of the bearing strength of deep slot-type foundations. A quantitative assessment of the end-bearing pile on the design stage of a building with a pile foundation is given, prerequisite is made for further studies of the action of end-bearing piles and development of design codes for various piles in terms of material, type of support action, methods of immersion in the soil, etc.

scholarly journals Flexural bearing capacity and failure mechanism of CFRP-aluminum laminate beam with double-channel cross-section

2021 ◽  
Vol 28 (1) ◽  
pp. 139-152
Author(s):  
Teng Huang ◽  
Dongdong Zhang ◽  
Yaxin Huang ◽  
Chengfei Fan ◽  
Yuan Lin ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Cross Section ◽  
Failure Criterion ◽  
Failure Modes ◽  
Channel Cross Section ◽  
Fiber Layer ◽  
Flexural Bearing Capacity ◽  
Double Channel

Abstract In this study, the flexural bearing capacity and failure mechanism of carbon fiber-reinforced aluminum laminate (CARALL) beams with a double-channel cross-section and a 3/2 laminated configuration were experimentally and numerically studied. Two types of specimens using different carbon fiber layup configurations ([0°/90°/0°]3 and [45°/0°/−45°]3) were fabricated using the pressure molding thermal curing forming process. The double-channel CARALL beams were subjected to static three-point bending tests to determine their failure behaviors in terms of ultimate bearing capacity and failure modes. Owing to the shortcomings of the two-dimensional Hashin failure criterion, the user-defined FORTRAN subroutine VUMAT suitable for the ABAQUS/Explicit solver and an analysis algorithm were established to obtain a progressive damage prediction of the CFRP layer using the three-dimensional Hashin failure criterion. Various failure behaviors and mechanisms of the CARALL beams were numerically analyzed. The results indicated that the numerical simulation was consistent with the experimental results for the ultimate bearing capacity and final failure modes, and the failure process of the double-channel CARALL beams could be revealed. The ultimate failure modes of both types of double-channel CARALL beams were local buckling deformation at the intersection of the upper flange and web near the concentrated loading position, which was mainly caused by the delamination failure among different unidirectional plates, tension and compression failure of the matrix, and shear failure of the fiber layers. The ability of each fiber layer to resist damage decreased in the order of 90° fiber layer > 0° fiber layer > 45° fiber layer. Thus, it is suggested that 90°, 0°, and 45° fiber layers should be stacked for double-channel CARALL beams.

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