Research on Application of Seismic Piezocone Penetration Tests in Pile Foundation

2011 ◽  
Vol 368-373 ◽  
pp. 2722-2730
Author(s):  
Quan Cao ◽  
Hong Chen ◽  
Fa Bo Chen
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Single Pile ◽  
In Situ Tests ◽  
Stress Theory ◽  
Theoretical Relationship ◽  
Wide Range ◽  
Penetration Tests

According to the characteristics of installation about the penetrometer of seismic piezocone penetration tests (SCPTu) and the 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 based on 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 application of seismic piezocone penetration tests have wide range in the pile foundation.

TIME TO THE END OF PRIMARY CONSOLIDATION (EOP) OF SOFT CLAYEY SOILS: CONCERNING THE EFFECT OF ATTERBERG’S LIMIT AND CYCLIC LOADING HISTORY

2019 ◽  
Vol 128 (2B) ◽  
pp. 29-41
Author(s):  
Trần Thanh Nhàn
Keyword(s):  
Cyclic Loading ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Clayey Soils ◽  
Loading History ◽  
Cyclic Shear ◽  
Wide Range ◽  
Primary Consolidation ◽  
Time Required

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.

scholarly journals Predicting the Performance of Highway Embankment Slopes

2019 ◽  
Vol 271 ◽  
pp. 02007
Author(s):  
Navid H. Jafari ◽  
Anand Puppala ◽  
Burak Boluk ◽  
Jack A. Cadigan ◽  
Sayantan Chakraborty ◽  
...  
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
High Plasticity ◽  
Soil Water Retention ◽  
Ring Shear ◽  
Wide Range ◽  
Van Genuchten Model ◽  
Ring Shear Tests ◽  
Highway Embankments ◽  
Marginal Condition

Resilience of transportation infrastructure, such as highway embankments, is critical to avoiding commuter delays and costly repairs. The majority of highway embankments in Louisiana and Texas are in marginal condition because the high-plasticity clays that are used during construction will moisten with time to significantly lower strengths. The ring shear tests demonstrate that the Gamez and Stark [1] empirical correlations are applicable to Texas and Louisiana soils. The soil water retention curves at each site were fitted to the Van Genuchten model [2]. For example, the air entry values vary from 0.013 to 0.053 kPa-1 in Louisiana and from 0.008 to 0.01 kPa-1 in Texas. The implications of this wide range of air entry values is that the matric suction pressure required to saturate and desaturate controls the pore-water pressure build-up during a rainfall event.

Numerical Analysis of the Influence of Vertical Load on the Horizontal Bearing Capacity of Single Pile

2011 ◽  
Vol 374-377 ◽  
pp. 1947-1952 ◽  
Author(s):  
Zhao Yun Xiao ◽  
Guo Xun Zhang ◽  
Wei Xu ◽  
Zhong Ming Xue
Keyword(s):  
Numerical Simulation ◽  
Bearing Capacity ◽  
Pile Foundation ◽  
Sandy Soils ◽  
Single Pile ◽  
Horizontal Load ◽  
Clayey Soils ◽  
Vertical Load ◽  
Concrete Pile ◽  
Finite Element Numerical Simulation

It is a complicated progress of interaction between pile and soil when pile is under both vertical load and horizontal load. This paper analyzes the variation of stress, strain, deformation and deflection of the pile body by finite element numerical simulation of single bored concrete pile under vertical load together with horizontal load. Based on the existing research results, conclusions could be that the vertical load can increase horizontal bearing capacity of the pile in sandy soils, but horizontal bearing capacity of the pile in clayey soils is more complicated. Hope that the simulation can provide some references for the design of pile foundation.

scholarly journals PENURUNAN OPRIT JEMBATAN SEMARANG LINGKAR UTARA DAN JEMBATAN KALI JAJAR DEMAK JAWA TENGAH DENGAN PRE-FABRICATED VERTICAL DRAIN

2021 ◽  
Vol 4 (1) ◽  
pp. 27
Author(s):  
M Zaki ◽  
Wardani SPR ◽  
Muhrozi Muhrozi
Keyword(s):  
Bearing Capacity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soil Improvement ◽  
Unit Weight ◽  
Fast Time ◽  
Foundation Soil ◽  
Vertical Drain ◽  
Long Time

<p><em>Construction on soft soil, often creates problems. The Semarang North Ring Bridge and Kali Jajar Bridge are the Recent soft Marine Alluvium zones located in the Pantura area which have very soft soil characteristics with a depth of more than -30.0 meters this has resulted in a very large settlement due to very small grains, flood, rob, pore water pressure increases so that the shear strength of the soil will be small, the compression is large and the permeability coefficient is small so that if the construction load exceeds the critical bearing capacity, the damage to the foundation soil will occur. To get the increase in soil bearing capacity, it can be achieved by changing the properties of the soil from the shear angle (</em>f<em>), cohesion (c) and unit weight (</em>g<em>). The settlement can be reduced by increasing the cavity density from the compression of the soil particles (Wesley, 1977). Soil improvement takes a long time, aiming to increase shear resistance so that it requires a fast time in this case is to use Pre-Fabricated Vertical Drain (Bowles 1981). The results of the analysis of the pattern of decline and the effectiveness of the use of PVD (pre-fabricated vertical drain) at the Oprit Bridge in the two research locations have the same decrease in the range of the same heap height at (H = 4 meters) there is a decrease of 117.53 cm at 64 months on the bridge. Kali Jajar (STA. 3 + 200) and there was a decrease of 268.94 cm at 37 months at the Semarang North Ring Bridge</em></p>

scholarly journals Calculation of Bearing Capacity and Deformation of Composite Pile Foundation with Long and Short Piles in Loess Areas

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Tianzhong Ma ◽  
Yanpeng Zhu ◽  
Xiaohui Yang
Keyword(s):  
Theoretical Calculation ◽  
Bearing Capacity ◽  
Pile Foundation ◽  
Frictional Resistance ◽  
Operating Conditions ◽  
Neutral Point ◽  
Pile Foundations ◽  
Single Pile ◽  
Deformation Control ◽  
Composite Pile

In order to calculate the bearing capacity and settlement deformation of composite pile foundations with long and short piles in collapsible loess areas, the theoretical approximate solution was used to obtain the location of the neutral point of single piles. Additionally, based on the equation to calculate the bearing capacity of multielement composite foundations, a method considering the negative frictional resistance was proposed for calculating the bearing capacity of composite pile foundations with long and short piles. Based on the shear displacement method and the principle of deformation control, an equation to calculate the displacement and deformation of a composite pile foundation was presented. A model test with different operating conditions, i.e., a single pile, four piles, and eight piles, was designed to verify the proposed calculation methods. The results show that the location of the neutral point has a significant influence on the single-pile negative frictional resistance, and the neutral point ratio of the calculation meets the value range of the practical project. When the load at the top of the pile is relatively small, the experimental curve is consistent with the theoretical calculation curve, whereas when the load is comparatively large, the theoretically calculated displacement increase at the top of the pile is greater than the measured one. Under the premise that the theoretical calculation is in good agreement with the results, the theoretical value is larger than the actual value. And it contributes to strengthening engineering safety.

Time Effect of the Pile Bearing Capacity in Dredger Fill

2013 ◽  
Vol 639-640 ◽  
pp. 630-638
Author(s):  
Hua Yang Lei ◽  
Qian Qian Lv
Keyword(s):  
Numerical Simulation ◽  
Bearing Capacity ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ultimate Bearing Capacity ◽  
Time Effect ◽  
Second Phase ◽  
Excess Pore Water Pressure ◽  
Excess Pore

The dissipating of pore water pressure caused by pile sinking is one of the main factors resulting in time effect of ultimate bearing capacity of pile.The pore water pressure is monitored at each observing point during pile sinking and after that. With the pore pressure plan embedded in advance, by means of spot test in the process of pile sinking, under this geological conditions of the pile foundation by referring to the second phase project of the free port logistics processing zone in Dongjiang, Tianjin.The change law of the distribution and dissipation of excess pore water pressure with time, depth, radial distance and permeability coefficient of soil was also discussed. It’s found that the excess pore water pressure attenuates approximately linearly with the increase of the distance from the pile heart and the scope influenced is around 10d. As the numerical simulation accord with the test results effectively, promote the results then get the change rule of pile bearing capacity with time.The formula of pile bearing capacity about time effect in dredge fill was deduced for engineering reference.The effect of soil internal friction angle on the ultimate bearing capacity of pile was discussed. Numerical simulation shows that the ultimate bearing capacity of pipe pile increases over time and keeps stable after 20d.The ultimate limit bearing capacity is 1473kN with increase of 12.3%, the time when it reaches the stable state is in accord with the excess pore water pressure dissipation monitored at each observing point. The larger the internal frictional angle of soil becomes, the more the ultimate bearing capacity is. The angle exceeding 20°,the bearing capacity would not increase as internal frictional angle of soil increases.

Centrifuge Study of the Effects of Lattice Leg on Penetration Resistance and Bearing Behavior of Spudcan Foundations in NC Clay

2012 ◽  
Author(s):  
Yu Ping Li ◽  
Fook Hou Lee ◽  
Siang Huat Goh ◽  
Jiang Tao Yi ◽  
Xi Ying Zhang
Keyword(s):  
Bearing Capacity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Clay ◽  
Penetration Resistance ◽  
Cavity Depth ◽  
Circular Column ◽  
Model Study ◽  
Vertical Bearing ◽  
Vertical Bearing Capacity

This paper reports the primary results of a centrifuge model study into the possible effects of the lattice leg on the penetration resistance and vertical bearing capacity of spudcan foundations in normally consolidated clay. Up to now, the possible effects of the lattice leg has been largely ignored in both research and design of spudcan foundation. Centrifuge experimental results show that there is an increase in penetration resistance for spudcan footing equipped with lattice leg, in comparison with spudcan footing connected to slender circular column leg as widely used by current research. Larger excess pore water pressure was generated by the spudcan penetration with lattice leg in compare with that without. Moreover, the presence of the lattice leg is shown to affect the cavity depth formed around the penetrated spudcan footing, which is simply assumed completely back flow for spudcan penetration in soft clay by SNAME (2008). It was found that the bearing capacity of spudcan foundation has been further underestimated by SNAME (2008) due to the neglecting of lattice leg effect. Taken altogether, this implies that changes in penetration resistance arising from the lattice leg may be due to the effect of the latter on the backflow pattern. Apart from highlighting the effect of the sleeve with big openings, the results also highlight the possible future use of sleeves to enhance the bearing capacity and possibly reduce the penetration of spudcan foundations in various soil deposits.

Development of a new calibration chamber for conducting cone penetration tests in unsaturated soils

2011 ◽  
Vol 48 (2) ◽  
pp. 314-321 ◽  
Author(s):  
Mohammad Pournaghiazar ◽  
Adrian R. Russell ◽  
Nasser Khalili
Keyword(s):  
Unsaturated Soils ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Bottom Plate ◽  
Cone Penetration ◽  
Rubber Membrane ◽  
Cone Penetration Tests ◽  
Horizontal Pressure ◽  
Calibration Chamber ◽  
Penetration Tests

A calibration chamber has been developed to conduct laboratory-controlled cone penetration tests in unsaturated soils. The chamber allows independent application of lateral and vertical pressures to an unsaturated soil specimen. Horizontal pressure is applied by cell water pressure pushing on a rubber membrane enclosing the specimen, while vertical pressure is maintained by a hydraulic loading ram at the base of the specimen. Suction is controlled using the axis-translation technique. Air pressure is applied to the top of the chamber where it spreads uniformly across the top of the specimen. Pore-water pressure is applied through eight high air-entry value porous disks embedded in the bottom plate. A particularly original aspect of the chamber design is the specimen formation system comprising four moveable cylinder quarters, which enables the creation of specimens of repeatable properties from a variety of soil types. The results of typical cone penetration tests conducted on dry, saturated, and unsaturated sand specimens are presented and highlight the contribution of suction to cone penetration resistance.

Research study of the hydraulic behaviour of the Po River embankments

2013 ◽  
Vol 50 (9) ◽  
pp. 947-960 ◽  
Author(s):  
Giovanni Calabresi ◽  
Francesco Colleselli ◽  
Domenico Danese ◽  
Gianpaolo Giani ◽  
Claudio Mancuso ◽  
...  
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Engineering Properties ◽  
In Situ Tests ◽  
Po River ◽  
Fine Grained ◽  
Hydraulic Behaviour ◽  
Two Dimensional Flow ◽  
Atmospheric Variables

To investigate the hydraulic behaviour of the fine-grained embankments along the mid-course of the Po River, research was carried out on a full-scale physical model, built on the floodplain along the existing embankment and forming a pond. The pond was filled to reproduce historical floods. The prototype was built according to recommendations formulated by the Po River Management Authority. The engineering properties of the foundation soils were investigated by in situ tests and complemented by some suction-controlled laboratory tests. Pore-water pressure was measured in the embankment and in its foundation before, during, and after the experimental reproduction of two floods that occurred in 1976 and 2000. Atmospheric variables were monitored at the prototype site. Monitoring data refer to 6 months of experimental activities. Pore-water pressure measurements were first presented and subsequently interpreted through an isothermal two-dimensional flow approach where boundary flow rates express the evolution of atmospheric variables. The distribution of the pore water provided by this interpretation was used for stability analyses of the prototype. Results from the experimental activities and their interpretation indicate that the river embankment remains extensively unsaturated during floods. Typical suction trends within the embankment, suction-associated soil strength, and the resulting slope stability safety factors are also shown.

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