Model Test and Study on Pile Foundation in Transversely Isotropy Clay

2011 ◽  
Vol 105-107 ◽  
pp. 1380-1384
Author(s):  
Zan Cheng Zhu ◽  
Fan Bo Guo ◽  
Feng Hua Jiang ◽  
Xiao Gang Wang
Keyword(s):  
Pile Foundation ◽  
Similarity Theory ◽  
Soft Clay ◽  
Plane Curve ◽  
Soil Surface ◽  
Test Point ◽  
Foundation Soil ◽  
Transversely Isotropy ◽  
Hyperbolic Curve ◽  
Shock Frequency

To further verify the feasibility of theoretic calculation, according to similarity theory, the principles and methods of pile foundation-soil interaction in saturated soft clay are determined. It studies acceleration interaction of each test point on the soil surface under the same largest shock force with different frequency on the top of the pile. The results of experiment show that the acceleration interaction trend of each point changes with the change of shock frequency, it shapes like a down N with the shock frequency of 5Hz, like an M with the shock frequency of 10Hz, like a down V under the shock frequency of 15Hz～30Hz. With the shock frequency of 40Hz and 50Hz, it likes a plane curve (hyperbolic curve) shape.

MODEL Test and Study of Vertical Loading Single Pile in Transversely Isotropy Clay

2011 ◽  
Vol 368-373 ◽  
pp. 85-88
Author(s):  
Zan Cheng Zhu ◽  
Feng Hua Jiang ◽  
Xiao Gang Wang
Keyword(s):  
Similarity Theory ◽  
Soil Surface ◽  
Test Point ◽  
Vertical Loading ◽  
Transversely Isotropy ◽  
Exciting Frequency ◽  
Transverse Isotropic ◽  
The Moment ◽  
Pile Model ◽  
Variation Trends

According to the basic idea of similarity theory, the pile model in saturated transverse isotropic clay is determined. It imitates the moment of different positions along the pile and acceleration of each test point on the soil surface, under the same largest exciting force with different frequencies on the top of the pile. The results of experiment show that the variation trends of the moment are the same for different frequencies of excitation, looking like an inverse S. Acceleration value of each test point on the soil surface decreases with decline of the exciting frequency.

Shake table study on seismic soil-pile foundation-structure interaction in soft clay

Structures ◽  
2021 ◽  
Vol 29 ◽  
pp. 1229-1241
Author(s):  
Swagata Deb Roy ◽  
Animesh Pandey ◽  
Rajib Saha
Keyword(s):  
Pile Foundation ◽  
Soft Clay ◽  
Shake Table ◽  
Structure Interaction ◽  
Foundation Structure

Feasibility Study of Lateral Buckling Using Residual Curvature Method for Deep Water Pipelines

2020 ◽  
Author(s):  
Qiang Bai ◽  
Fengbin Xu ◽  
Mark Brunner
Keyword(s):  
Deep Water ◽  
Twist Angle ◽  
Soft Clay ◽  
Soil Surface ◽  
Lateral Buckling ◽  
Finite Element Software ◽  
User Subroutine ◽  
Maximum Value ◽  
Water Pipelines ◽  
Residual Curvature

Abstract In recent years the residual curvature (RC) method has been used to provide buckle initiators to control and mitigate the lateral buckling of pipelines for some shallow water projects. With the appropriate planning of the controlled buckles using RC sections, an acceptable design of the pipeline in-place behavior is achieved. However, the RC method has not yet been applied to deep-water pipelines. The twist of RC sections in the sagbend during installation has been observed, and the orientation of as-laid RC section on the seabed is difficult to control in deep-water pipelines. The effects of as-laid RC-section orientation on in-place lateral buckling in deep water are unknown. The FRIC user subroutine in the Abaqus finite-element software suite has been developed for modelling pipe-soil interactions based on uncoupled axial and lateral soil resistances that are assumed to be independent of vertical pipe penetration after initial embedment into the soil surface. However, the penetration of a twisted RC section can vary dramatically from a normal pipeline on the seabed. The UINTER user subroutine in Abaqus was selected for presenting 3D pipe-soil interactions that incorporate the variations of independent axial and lateral soil resistances as a function of pipe penetration more accurately. UINTER is used in the present study to account for the effects of soil penetration on the lateral buckling performance of a pipeline with RC sections in soft clay. The analysis results show that the RC section twists in the sagbend area during installation, and the twist angle reaches its maximum value just prior to the RC section touching the seabed. The in-place lateral buckling analysis is carried out after the installation analysis is finished. The analysis results demonstrate the feasibility of applying the RC method as the primary buckle triggering mechanism for deep water pipelines, and it shows how the RC orientation affects the pipeline in-place performance in terms of strength and fatigue damage (only the stress ranges for use in fatigue calculations are shown in the paper).

Predicting the overall horizontal bearing capacity of jack-up rigs using deck–foundation–soil-coupled model

2020 ◽  
pp. 147509022092590
Author(s):  
Qilin Yin ◽  
Jinjin Zhai ◽  
Sheng Dong
Keyword(s):  
Bearing Capacity ◽  
Failure Mode ◽  
Double Layer ◽  
Soft Clay ◽  
Coupled Model ◽  
Single Layer ◽  
Horizontal Load ◽  
Foundation Soil ◽  
Failure Envelopes ◽  
Jack Up

The overall bearing capacity of a jack-up rig under horizontal load is conducted using finite element models that consider the deck–foundation–soil interaction. In these models, the simplified horizontal load acts on the deck and increases until the platform loses its stability. The effects of the self-weight of the platform W and load direction α on the ultimate horizontal bearing capacity Hult are investigated, and W- Hult failure envelopes under different α conditions are obtained. Two typical seabed types, including the double-layer seabed of sand overlying soft clay and the single-layer seabed of sand, are considered. The results show that a critical self-weight Wcritical exists in the double-layer seabed. Based on Wcritical, the failure of the platform presents two different modes. When W <  Wcritical, the windward leg is pulled up, and Hult increases with the increase in W. When W >  Wcritical, the failure mode is the leeward leg or legs puncturing the bearing sand layer, and Hult decreases with the increase in W. In the single-layer seabed, the failure mode is the windward leg being pulled up, and Hult increases with the increase in W throughout the whole range. The W- Hult envelopes in these two types of seabeds are basically the same when W <  Wcritical.

Negative skin friction from surface settlement measurements in model group tests

1995 ◽  
Vol 32 (6) ◽  
pp. 1075-1079 ◽  
Author(s):  
Mehmet Ufuk Ergun ◽  
Devrim Sönmez
Keyword(s):  
Soft Clay ◽  
Soil Surface ◽  
Pile Group ◽  
Friction Model ◽  
Model Group ◽  
Pile Groups ◽  
Negative Skin Friction ◽  
Dense Sand ◽  
Model Study ◽  
Negative Friction

Groups of model wood piles driven to end bearing through dense sand over soft clay were used to determine the relative settlement of the soil surface inside and outside the groups as the soil was compressed by air pressure. Square 30 mm piles at spacings of 2 to 6 times the pile width were used in groups of 3 × 3, 4 × 4, and 5 × 5. The results indicate that pile group effects were negligible at pile spacings at 5 to 6 pile widths. Key words : negative friction, model study, pile groups, sand.

Pile Foundation Antifreezing Measures Research in Seasonal Frozen Soil Region

2014 ◽  
Vol 578-579 ◽  
pp. 767-771 ◽  
Author(s):  
Ji Qiang Song
Keyword(s):  
Water Content ◽  
Water Level ◽  
Pile Foundation ◽  
Underground Water ◽  
Frozen Soil ◽  
Foundation Soil ◽  
Freeze Injury ◽  
Seasonal Frozen Soil ◽  
Bored Piles ◽  
Underground Water Level

Canal bridge and aqueduct main foundation types include well column, pier, bored piles, bent pile etc. Most of these foundations are in low-lying conduit. The water content of foundation soil is very rich. Especially pile foundation in the drain, due to the high underground water level, pile foundation around soil is in a state full of water. So such type of foundation freeze injury phenomenons are very serious. In order to solve such freeze injury problems, some antifreezing measures are adopted.

scholarly journals PENGARUH JARAK DAN POLA PREFABRICATED VERTICAL DRAIN (PVD) PADA PERBAIKAN TANAH LEMPUNG LUNAK = EFFECT OF DISTANCE AND PATTERN OF PREFABRICATED VERTICAL DRAIN FOR IMPROVEMENT OF SOFT CLAY SOIL

2016 ◽  
Vol 10 (1) ◽  
pp. 41-50
Author(s):  
Wimpie Agoeng Noegroho Aspara ◽  
Eka Nur Fitriani
Keyword(s):  
Clay Soil ◽  
Soft Soil ◽  
Soft Clay ◽  
Analytical Calculation ◽  
Drainage System ◽  
Coefficient Of Consolidation ◽  
Consolidation Process ◽  
Foundation Soil ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain

AbstractIf a structure for reasons of technical, economic, social, or startegic is to be built on a soft ground, then there are usually two problems to be solved, namely the low geotechnical bearing capacity and large soil deformation with sometimes differential settlement. Pre-compression is a foundation soil compression process with the provision of temporary loading (preloading) before actually constructing a building. Pre-fabricated vertical drain is a synthetic drainage system installed vertically inside soft soil layers. Soil condition at the project activity is a relatively very soft clay soil with relatively high coefficient of consolidation resulting in very long period of consolidation process. Therefore, it is needed advance soil improvement by prealoding of pre-fabricated vertical drain. Spacings of installed PVD vary, those are 50 cm, 100 cm, 150 cm, and 200 cm with a pattern of triangles and rectangles. Based on the analytical calculation, it is resulted that optimum PVD distance to achieve 90% consolidation is 150 cm with a triangular pattern. The time of consolidation was achieved within four months. AbstrakKetika suatu struktur karena alasan-alasan teknis, ekonomi, sosial, atau strategis terpaksa didirikan di atas tanah lunak, maka biasanya ada dua masalah geoteknik yang harus dipecahkan yaitu daya dukung yang rendah dan penurunan serta beda penurunan yang besar. Prakompresi adalah suatu proses pemampatan tanah pondasi dengan jalan pemberian pembebanan sementara (prabeban/preloading) sebelum konstruksi yang sesungguhnya didirikan. Prefabricated vertical drain (PVD) adalah sistem drainase buatan yang dipasang vertikal di dalam lapisan tanah lunak. Kondisi tanah di lokasi kegiatan relatif sangat lunak dengan koefisien konsolidasi relatif sangat tinggi mengakibatkan proses konsolidasi berjalan relatif sangat lama. Untuk itu diperlukan perbaikan tanah terlebih dahulu dengan prealoading menggunakan PVD. Jarak spasi antar PVD yang dipasang bervaiasi yaitu 50 cm, 100 cm, 150 cm, dan 200 cm dengan pola konfigurasi segitiga dan segiempat. Berdasarkan hasil perhitungan secara analitis didapatkan jarak optimum PVD untuk mencapai konsolidasi 90% adalah 150 cm dengan pola segitiga dengan proses konsolidasi dicapai selama waktu penurunan 4 bulan.

Sign in / Sign up

Export Citation Format

Share Document