Behaviour of flexible piles under inclined loads

1990 ◽  
Vol 27 (1) ◽  
pp. 19-28 ◽  
Author(s):  
V. V. R. N. Sastry ◽  
G. G. Meyerhof
Keyword(s):  
Soft Clay ◽  
Ground Surface ◽  
Embedment Depth ◽  
Loose Sand ◽  
Bending Moments ◽  
Soil Pressure ◽  
Inclined Loads ◽  
Load Tests ◽  
Test Pile ◽  
Flexible Model

The lateral soil pressures, bending moments, pile displacements at ground surface, and bearing capacity of instrumented vertical single flexible model piles in homogeneous loose sand and soft clay under central inclined loads have been investigated. The results of these load tests are compared with theoretical estimates based on the concept of an effective embedment depth of equivalent rigid piles. Reasonable agreement has been found between the observed and predicted behaviour of flexible piles. The analyses are also compared with the results of some field case records. Key words: bending moments, clay, displacements, inclined loads, instrumentation, lateral soil pressure, model test, pile, sand.

Behaviour of flexible piles in layered sands under eccentric and inclined loads

1994 ◽  
Vol 31 (4) ◽  
pp. 513-520 ◽  
Author(s):  
V.V.R.N. Sastry ◽  
G.G. Meyerhof
Keyword(s):  
Bearing Capacity ◽  
Reasonable Agreement ◽  
Ground Surface ◽  
Embedment Depth ◽  
Loose Sand ◽  
Bending Moments ◽  
Inclined Loads ◽  
Load Tests ◽  
Flexible Model ◽  
Compact Sand

The lateral soil pressures, bending moments, pile displacements at ground surface, and bearing capacity of instrumented vertical single flexible model piles in layered sands consisting of loose sand overlying compact sand under vertical eccentric and central inclined loads have been investigated. The results of these load tests are compared with theoretical estimates based on the concept of an effective embedment depth of equivalent rigid piles. Reasonable agreement has been found between the observed and predicted behaviour of flexible piles. The analyses are also compared with the results of some field case records. Key words : bearing capacity, instrumentation, model test, layered soil, pile, sand.

Behaviour of flexible piles in layered clays under eccentric and inclined loads

1995 ◽  
Vol 32 (3) ◽  
pp. 387-396 ◽  
Author(s):  
V.V.R.N. Sastry ◽  
G.G. Meyerhof
Keyword(s):  
Bearing Capacity ◽  
Soft Clay ◽  
Ground Surface ◽  
Embedment Depth ◽  
Layered Clays ◽  
Inclined Loads ◽  
Clay System ◽  
Load Tests ◽  
Layered Clay ◽  
Test Pile

The lateral soil pressures, bending moments, pile displacements at the ground surface, and the bearing capacity of instrumented vertical single flexible model piles in a layered clay system consisting of medium clay overlying soft clay under vertical eccentric and central inclined loads have been investigated. The results of these load tests are compared with theoretical estimates based on the concept of the effective embedment depth of equivalent rigid piles for ultimate and elastic cases. Reasonable agreement has been found between the observed and predicted behaviour of flexible piles. The analyses are also compared with the results of some field case records. Key words : bearing capacity, clay, instrumentation, model test, pile.

Bearing capacity of rigid piles under eccentric and inclined loads

1985 ◽  
Vol 22 (3) ◽  
pp. 267-276 ◽  
Author(s):  
G. G. Meyerhof ◽  
V. V. R. N. Sastry
Keyword(s):  
Bearing Capacity ◽  
Soft Clay ◽  
Horizontal Load ◽  
Soil Pressure ◽  
Pile Capacity ◽  
Inclined Loads ◽  
Pure Moment ◽  
Load Tests ◽  
Rigid Model ◽  
Test Pile

The ultimate bearing capacity of instrumented vertical single rigid model piles in homogeneous loose sand and soft clay under vertical eccentric and central inclined loads has been investigated. The results of these load tests provide a more realistic lateral soil pressure distribution on the pile shaft and better theoretical estimates of pile capacity under pure moment and under horizontal load. For intermediate eccentricities and inclinations of the load, the bearing capacity can be obtained from simple interaction relationships between the axial load and moment capacities and between the axial and horizontal load capacities, respectively. The influence of lateral soil pressures due to installation of displacement piles in clay is examined in relation to the ultimate load of the pile. The analyses are compared with the results of model tests and some field case records. Key words: bearing capacity, clay, eccentric loading, horizontal load, instrumentation, model test, pile, sand.

Ultimate capacity of flexible piles under eccentric and inclined loads

1989 ◽  
Vol 26 (1) ◽  
pp. 34-42 ◽  
Author(s):  
G. G. Meyerhof ◽  
D. P. Ghosh
Keyword(s):  
Bearing Capacity ◽  
Soft Clay ◽  
Ultimate Bearing Capacity ◽  
Embedment Depth ◽  
Pile Groups ◽  
Single Model ◽  
Eccentric Load ◽  
Inclined Loads ◽  
Load Tests ◽  
Ultimate Moment

The ultimate bearing capacity of flexible single model piles and small pile groups of timber and nylon in loose sand and soft clay has been determined under various combinations of eccentricity and inclination of the load varying in direction from vertical to horizontal. The results of the load tests are presented in the form of polar bearing capacity diagrams and they are compared with the theoretical estimates based on the concept of an effective embedment depth in terms of the behaviour of equivalent rigid piles. Reasonable agreement has been found between the observed and predicted ultimate bearing capacity of flexible piles under any combination of eccentricity and inclination of loads. Key words: flexible piles, pile groups, ultimate bearing capacity, ultimate moment, model test, eccentric load, inclined load, sand, clay.

Lateral soil pressures and displacements of rigid piles in homogeneous soils under eccentric and inclined loads

1986 ◽  
Vol 23 (3) ◽  
pp. 281-286 ◽  
Author(s):  
V. V. R. N. Sastry ◽  
G. G. Meyerhof
Keyword(s):  
Soft Clay ◽  
Test Results ◽  
Soil Pressure ◽  
Eccentric Load ◽  
Load Range ◽  
Pressure Distributions ◽  
Inclined Loads ◽  
Rigid Model ◽  
Test Pile ◽  
Theoretical Pressure

The lateral soil pressures, tip load, and displacements of instrumented single rigid model piles in homogeneous loose sand and soft clay under vertical eccentric and central inclined loads have been investigated. A comparison of the test results with theoretical pressure distributions and displacements of the pile for the working load range has been made. Reasonable agreement has been found between the observed and predicted displacements and suggested nondimensional p–y curves. The analyses are also compared with the results of some field case records. Key words: displacements, clay, eccentric load, horizontal load, lateral soil pressure, instrumentation, model test, pile, sand.

scholarly journals Compression Load Tests on Composite Foundations of Spread Footing Anchored by Helical Anchors

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Mingqiang Sheng ◽  
Zengzhen Qian ◽  
Xianlong Lu
Keyword(s):  
Composite Foundation ◽  
Embedment Depth ◽  
Load Testing ◽  
Soil Pressure ◽  
Foundation Soil ◽  
Total Load ◽  
Compression Load ◽  
Spread Footing ◽  
Interpretation Criteria ◽  
Load Tests

This study elucidates the compression behavior of a type of composite foundation of spread footing anchored by helical anchors. Three composite foundations were installed at a field site, and compression load testing was carried out on each foundation. Both the site conditions and the load tests were documented comprehensively. The compression load-settlement curves of composite foundations exhibit an initial linear-elastic segment, a curve transition, and a final linear region, and their capacities should be interpreted from the load-settlement curves. Five representative interpretation criteria (Chin, Terzaghi and Peck, slope tangent, tangent intersection, and L1–L2) were employed to determine the capacity of each foundation. Both the helical anchors and the footing share compression loadings on the composite foundation. Soil pressure cells at the center, near the edge, and at the corner of the footing represent a distribution from the lower, middle, and higher ranges of incremental soil pressures underneath the footing. Helical anchors underneath the footing approximately share 60%–80% of total load applied on the composite foundation pier, and higher compression resistance of a composite foundation can be obtained by increasing the footing embedment depth and the number of helical anchors underneath the footing.

scholarly journals Seismic Behavior of Triple Tunnel Complex in Soft Soil Subjected to Transverse Shaking

2020 ◽  
Vol 10 (1) ◽  
pp. 334
Author(s):  
Ahsan Naseem ◽  
Muhammad Kashif ◽  
Nouman Iqbal ◽  
Ken Schotte ◽  
Hans De Backer
Keyword(s):  
Soft Soil ◽  
Ground Surface ◽  
Sharp Decrease ◽  
Soil Mass ◽  
Embedment Depth ◽  
Bending Moments ◽  
Ground Shaking ◽  
Complex Needs ◽  
Seismic Vibrations ◽  
Ground Displacements

Combining multiple tunnels into a single tunnel complex while keeping the surrounding area compact is a complicated procedure. The condition becomes more complex when soft soil is present and the area is prone to seismic activity. Seismic vibrations produce sudden ground shaking, which causes a sharp decrease in the shear strength and bearing capacity of the soil. This results in larger ground displacements and deformation of structures located at the surface and within the soil mass. The deformations are more pronounced at shallower depths and near the ground surface. Tunnels located in that area are also affected and can undergo excessive distortions and uplift. The condition becomes worse if the tunnel area is larger, and, thus, the respective tunnel complex needs to be properly evaluated. In this research, a novel triple tunnel complex formed by combining three closely spaced tunnels is numerically analyzed using Plaxis 2D software under variable dynamic loadings. The effect of variations in lining thickness, the inner supporting structure, embedment depth on the produced ground displacements, tunnel deformations, resisting bending moments, and the developed thrusts are studied in detail. The triple tunnel complex is also compared with the rectangular and equivalent horizontal twin tunnel complexes in terms of generated thrusts and resisted seismic-induced bending moments. From the results, it is concluded that increased thickness of the lining, inner structure, and greater embedment depth results in decreased ground displacements, tunnel deformations, and increased resistance to seismic-induced bending moments. The comparison of shapes revealed that the triple tunnel complex has better resistance against moments with the least amount of thrust and surface heave produced.

Static cone tests and settlement of calcareous desert sands

1986 ◽  
Vol 23 (3) ◽  
pp. 297-303 ◽  
Author(s):  
Nabil F. Ismael ◽  
Abdul Majeed Jeragh
Keyword(s):  
Ground Surface ◽  
Field Tests ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Cone Penetration ◽  
Soil Pressure ◽  
Cone Penetration Tests ◽  
Below Ground ◽  
Load Tests ◽  
Penetration Tests

The results of a recent in situ testing program to establish standard penetration test – cone penetration test (SPT–CPT) correlation for the windblown calcareous desert sands of Kuwait are presented and analyzed. The program consisted of auger borings and static cone tests at five sites along a 35 km long corridor. The resulting correlation was employed for prediction of the allowable soil pressure of footings at seven sites in Kuwait where load tests were carried out on square concrete footings placed at a depth of 1 m below ground surface. A comparison of the measured to the predicted soil pressures using the Schmertmann method indicated very close agreement. The average ratio of measured to predicted soil pressure is 93% for the seven test sites. Recommendations are made for further testing to determine the long-term settlement components due to creep and cyclic loading. Key words: load tests, sands, footings, allowable pressure, settlement, field tests, borings, cone penetration tests.

Contrôle de la stabilité des remblais par la mesure des déplacements horizontaux

1974 ◽  
Vol 11 (1) ◽  
pp. 182-201 ◽  
Author(s):  
René Marche ◽  
Robert Chapuis
Keyword(s):  
Factor Of Safety ◽  
Soft Clay ◽  
Ground Surface ◽  
Soft Layer ◽  
The Stability ◽  
Horizontal Displacements

The horizontal displacements measured at the toe of eight embankments are analyzed as a function of the factor of safety. The embankments are built on layers of soft clay. Only the undrained stage is studied.When the factor of safety of the embankments is higher than about 1.4, the horizontal displacements on the ground surface, at the toe of the embankment seem to follow an elastic law which is highly dependent on the ratio of the thickness of the soft layer to the width of the embankment. When the factor of safety is lower than about 1.4, the horizontal displacements do not follow an elastic law, they increase considerably. Consequently, it is suggested that the horizontal displacements be precisely measured at the toe of embankments during construction. These measurements are simple and sensitive to the approach of failure, they can be efficiently used to control the stability of embankments. This study also gives some information concerning the variation of horizontal displacements versus depth.

RESPONSE OF SOFT CLAY STRATA AND CLAY-PILE-RAFT SYSTEMS TO SEISMIC SHAKING

2007 ◽  
Vol 01 (03) ◽  
pp. 233-255 ◽  
Author(s):  
SUBHADEEP BANERJEE ◽  
SIANG HUAT GOH ◽  
FOOK HOU LEE
Keyword(s):  
Soft Clay ◽  
Ground Surface ◽  
Model Tests ◽  
Pile Foundations ◽  
Kaolin Clay ◽  
Natural Period ◽  
Soil System ◽  
Centrifuge Model ◽  
Inertial Loading ◽  
Centrifuge Model Tests

The behavior of pile foundations under earthquake loading is an important factor affecting the performance of structures. Observations from past earthquakes have shown that piles in firm soils generally perform well, while the performance of piles in soft or liquefied ground can raise some questions. Centrifuge model tests were carried out at the National University of Singapore to investigate the response of pile-soil system under three different earthquake excitations. Some initial tests were done on kaolin clay beds to understand the pure clay behavior under repetitive earthquake shaking. Pile foundations comprising of solid steel, hollow steel and hollow steel pile filled with cement in-fill were then embedded in the kaolin clay beds to study the response of clay-pile system. Superstructural inertial loading on the foundation was modeled by fastening steel weight on top of the model raft. The model test results show that strain softening and stiffness degradation feature strongly in the behaviour of the clay. In uniform clay beds without piles, this is manifested as an increase in resonance periods of the surface response with level of shaking and with successive earthquakes. For the pile systems tested, the effect of the surrounding soft clay was primarily to impose an inertial loading onto the piles, thereby increasing the natural period of the piles over and above that of the pile foundation alone. There is also some evidence that the relative motion between piles and soil leads to aggravated softening of the soil around the pile, thereby lengthening its resonance period of the soil further. The centrifuge model tests were back-analyzed using the finite element code ABAQUS. The analysis shows that the simple non-linear hypoelastic soil model gave reasonably good agreement with the experimental observations. The engineering implication arising from this study so far is that, for the case of relatively short piles in soft clays, the ground surface motions may not be representative of the raft motion. Other than the very small earthquakes, the raft motion has a shorter resonance period than the surrounding soil.

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