scholarly journals Field Study on Deformation and Stress Characteristics of Large Open Caisson during Excavation in Deep Marine Soft Clay

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xin Yan ◽  
Wei Zhan ◽  
Zhi Hu ◽  
Danqiang Xiao ◽  
Yiqiang Yu ◽  
...  
Keyword(s):  
Torsion Angle ◽  
Soft Soil ◽  
Reaction Force ◽  
Soft Clay ◽  
Reference Value ◽  
Suspension Bridge ◽  
Soil Pressure ◽  
Good Opportunity ◽  
Time To Build ◽  
Tip Resistance

Oujiang River North Estuary Bridge in Wenzhou is the world’s first double-deck suspension bridge under construction with three-tower and four-span. It is the first time to build large open caisson foundation in the deep marine soft clay in estuary with strong tide, extending the application scope of caisson. To study the deformation and stress characteristics of large open caisson during excavation and ensure the safety of anchorage excavation, a large number of sensors are arranged in the caisson. By analyzing the change of tip resistance, lateral soil pressure, and posture parameters during caisson excavation, the stress characteristics and deformation of caisson are described. The result shows the following. (1) Because of the thixotropy of soft clay, the reaction force of partition wall in deep soft soil area of caisson is similar to that of blade foot, and the reaction force of blade foot can be effectively reduced through the layering construction of caisson. (2) The height of caisson construction and the sand-bearing stratum will obviously affect the plane torsion angle of caisson. When the caisson enters the sand-bearing stratum, the lateral soil pressure increases significantly, which leads to the increase of the plane torsion angle. (3) The inclination and central deviation of caisson are sensitive to the caisson construction and stratum property. It can be found that the lateral soil pressure, plane torsion angle, inclination, and central deviation of caisson are sensitive to stratum property, and inhomogeneity of stratum easily leads to inclination of caisson. Based on the field monitoring data, the stress characteristics and geometric posture of caisson during sinking are studied, which provide technical guidance for scheme design and subsidence prediction analysis of caisson in deep marine soft clay. It can provide a good opportunity to study the behaviors of large caisson foundation constructed in deep marine soft clay and has great significance and reference value for construction optimization of anchorage structure.

Behavior of Micropiles in Soft Soil under Vertical Loading

2011 ◽  
Vol 243-249 ◽  
pp. 2143-2150 ◽  
Author(s):  
Zen Zheng Qian ◽  
Xian Long Lu
Keyword(s):  
Linear Trend ◽  
Load Capacity ◽  
Soft Soil ◽  
Soft Clay ◽  
Field Tests ◽  
Silty Clay ◽  
Compression Load ◽  
Vertical Loading ◽  
Tip Resistance ◽  
Tension Loading

The behavior of micropiles in soft clay, under vertical compression and tension loading, was examined by field tests at a site in Shanghai. The soil profile consists of topsoil, silty clay, sandy silt, muddy clay, and clay soil. Two compression and three tension loading tests were conducted on five single micropiles. The piles were instrumented with vibrating wire force sensors, and they were monitored during the process of loading to investigate the mechanisms of load transfer. Both the ultimate vertical load capacity and the deflection at applied loads were examined. The results indicate that the pile load–displacement response under vertical compression or tension loadings was nonlinear. Both the compression and the tension load carrying capacity basically increased with a linear trend. But, the ultimate load capacities under tension were about 50-60% of those under compression. Tip resistance was about 10-15% of the applied compression load, not existing in the micropiles under tension. The average skin friction for micropiles under compression loading was about 50% higher than that for piles under tension loading.

Uplift and Settlement Prediction Model of Marine Clay Soil e Integrated with Polyurethane Foam

2019 ◽  
Vol 9 (1) ◽  
pp. 481-489
Author(s):  
D.C. Lat ◽  
I.B.M. Jais ◽  
N. Ali ◽  
B. Baharom ◽  
N.Z. Mohd Yunus ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Clay Soil ◽  
Ground Improvement ◽  
Soft Soil ◽  
Soft Clay ◽  
Effective Thickness ◽  
Marine Clay ◽  
Uplift Pressure ◽  
Pu Foam ◽  
Improvement Method

AbstractPolyurethane (PU) foam is a lightweight material that can be used efficiently as a ground improvement method in solving excessive and differential settlement of soil foundation mainly for infrastructures such as road, highway and parking spaces. The ground improvement method is done by excavation and removal of soft soil at shallow depth and replacement with lightweight PU foam slab. This study is done to simulate the model of marine clay soil integrated with polyurethane foam using finite element method (FEM) PLAXIS 2D for prediction of settlement behavior and uplift effect due to polyurethane foam mitigation method. Model of soft clay foundation stabilized with PU foam slab with variation in thickness and overburden loads were analyzed. Results from FEM exhibited the same trend as the results of the analytical method whereby PU foam has successfully reduced the amount of settlement significantly. With the increase in PU foam thickness, the settlement is reduced, nonetheless the uplift pressure starts to increase beyond the line of effective thickness. PU foam design chart has been produced for practical application in order to adopt the effective thickness of PU foam within tolerable settlement value and uplift pressure with respect to different overburden loads for ground improvement works.

Experimental Study of the Rotary Filling Piles with Large-Diameter under the Axial Load

2012 ◽  
Vol 594-597 ◽  
pp. 527-531
Author(s):  
Wan Qing Zhou ◽  
Shun Pei Ouyang
Keyword(s):  
Experimental Study ◽  
Axial Load ◽  
Load Transfer ◽  
Soft Soil ◽  
Large Diameter ◽  
Shaft Resistance ◽  
Tip Resistance ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Deep Soft Soil

Based on the experimental study of rotary filling piles with large diameter subjected to axial load in deep soft soil, the bearing capacity behavior and load transfer mechanism were discussed. Results show that in deep soft soil foundation, the super–long piles behave as end-bearing frictional piles. The exertion of the shaft resistance is not synchronized. The upper layer of soil is exerted prior to the lower part of soil. Meanwhile, the exertion of shaft resistance is prior to the tip resistance. For the different soil and the different depth of the same layer of soil, shaft resistance is different.

Nonlinear Finite Element Analysis of Super-Long Pile and Soil Interaction in Soft Soil

2011 ◽  
Vol 201-203 ◽  
pp. 1601-1605 ◽  
Author(s):  
Shang Ping Chen ◽  
Wen Juan Yao ◽  
Sheng Qing Zhu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Soft Soil ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Element Analysis ◽  
Friction Resistance ◽  
Tip Resistance ◽  
Side Friction

In this paper, a nonlinear three-dimensional finite element model for super-long pile and soil interaction is established. In this model, contact elements are applied to simulate the nonlinear behavior of interaction of super-long pile and soil. A nonlinear elastic constitutive model for concrete is employed to analyze stress-strain relation of pile shaft under the axial load and the Duncan-Chang’s nonlinear constitutive model is used to reflect nonlinear and inelastic properties of soil. The side friction resistance, axial force, pile-tip resistance, and developing trend of soil plastic deformation are obtained and compared with measured results from static load tests. It is demonstrated that a super-long pile has the properties of degradation of side friction resistance and asynchronous action between side and pile-tip resistance, which is different from piles with a short to medium length.

scholarly journals Compaction and Plasticity Comparative Behaviour of Soft Clay Treated with Coarse and Fine Sizes of Ceramic Tiles

2018 ◽  
Vol 34 ◽  
pp. 01012 ◽  
Author(s):  
Mohammed Ali Mohammed Al-Bared ◽  
Aminaton Marto ◽  
Indra Sati Hamonangan Harahap ◽  
Fauziah Kasim
Keyword(s):  
Soil Stabilization ◽  
Soft Soil ◽  
Soft Clay ◽  
Cost Effective ◽  
Dry Weight ◽  
Dry Density ◽  
Ceramic Tiles ◽  
Marine Clay ◽  
Maximum Dry Density ◽  
Stiff Soil

Recycled blended ceramic tiles (RBT) is a waste material produced from ceramic tile factories and construction activities. RBT is found to be cost effective, sustainable, environmental-friendly and has the potential to be used as an additive in soft soil stabilization. Recent reports show that massive amounts of RBT are dumped into legal or illegal landfills every year consuming very large spaces and creating major environmental problems. On the other hand, dredged marine clay obtained from Nusajaya, Johor, Malaysia has weak physical and engineering characteristics to be considered as unsuitable soft soil that is usually excavated, dumped into landfills and replaced by stiff soil. Hence, this study investigates the suitability of possible uses of RBT to treat marine clay. Laboratory tests included Standard proctor tests and Atterberg limits tests. The plasticity of marine clay was evaluated by adding 10%, 20%, 30% and 40% of 0.3 mm RBT. In addition, the compaction behaviour of treated marine clay was compared by adding two different sizes (0.3 mm and 1.18 mm diameter) of RBT. For both coarse and fine sizes of RBT, 10%, 20%, 30% and 40% of the dry weight of the soft clay were added. The mixture of each combination was examined in order to evaluate the Maximum Dry Density (MDD) and the optimum moisture content (OMC) for the treated soft clay. MDD and OMC for soft untreated samples were 1.59 Mg/m3 and 22%, respectively. Treated samples with 10%, 20%, 30% and 40% of 0.30 mm size RBT resulted in a significant reduction of OMC ranged from 19 to 15% while MDD resulted in increment ranged from 1.69 to 1.77 Mg/m3. In addition, samples treated with 10%, 20%, 30% and 40% of 1.18 mm size RBT resulted in major reduction of OMC ranged from 15 to 13.5% while MDD increased effectively from 1.75 to 1.82 Mg/m3. For all mix designs of soft clay-RBT, MDD was gradually increasing and OMC was sharply reducing with further increments of both sizes of RBT.

scholarly journals Numerical Modelling of Prefabricated Vertical Drain for Soft Clay Using ABAQUS

2015 ◽  
Vol 773-774 ◽  
pp. 1502-1507
Author(s):  
Saiful Azhar Ahmad Tajudin ◽  
Mohd Fairus Yusof ◽  
I. Bakar ◽  
Aminaton Marto ◽  
Muhammad Nizam Zakaria ◽  
...  
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soft Clay ◽  
Elastic Model ◽  
Clay Layer ◽  
Soil Consolidation ◽  
Consolidation Process ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain

Construction, buildings and infrastructure founded on soft clays are often affected by settlement problem. Therefore, Prefabricated Vertical Drain (PVD) is one of the best solutions to accelerate soil consolidation by shortening the drainage path. In this study, numerical investigation was carried out to pursue a better understanding of the consolidation behavior of soft clay improved with PVD. The consolidation process accelerated by PVD with surcharge of 50 kPa was analysed using the ABAQUS software by adopting an elastic model. The aim of this study is to compare the settlement and the required time to fully consolidate the soft soil at different drain spacings (1.0 m, 1.5 m and 2.0 m) for two different thickness of the clay layer. The results shows that the time required to completely consolidate the soft soil for 12 m and 20 m thickness of clay layer with different spacings are in the range of 3 months to 66 months. The settlement rate and excess pore water pressure dissipation are increased when the spacing of the drain closer.

The Effect of Heat Induction on Shear Strength of Soft Soil in Radial Zone

2020 ◽  
Vol 998 ◽  
pp. 329-334
Author(s):  
Maraden Panjaitan ◽  
Lawalenna Samang ◽  
Achmad Bakri Muhiddin ◽  
Tri Harianto
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Soft Soil ◽  
Soft Clay ◽  
Experimental Result ◽  
Small Scale ◽  
Infrastructure Development ◽  
Heat Induction ◽  
Vane Shear Test ◽  
Radial Zone

The main problem in infrastructure development at the soft clay was its bearing capacity therefore it needs to be improved. In this research, the improvement method was carried out by modeling in small scale of preloading and heat induction combination. Location of soft clay sampling was in Takalar, Indonesia. The purpose of this study was to investigate the change of the shear strength of soft soil corresponding with heat induction at the radial zone. The shear strength was obtained by vane shear test and compressive strength from unconfined compressive test (UCT). The heat applied ranging from 100o C, 200o C, 300o C, and 400o C with static preloading load 0.20 kg/cm2. The strengths of the soil in radial zones have been tested at R0, R1, and R2. At lowest temperature 100° at R0 the compressive strength was 0.203 kg/cm2, at highest temperature 400° at R0 the compressive strength 0.467 kg/cm2, there was a significant increasing of compressive strength value with the change of temperature. At the highest temperature 4000 the shear strength from vane shear tests resulting at R0 0.240 kg/cm2, R1 of 0.128 kg/cm2, R2 of 0.077 kg/cm2. At the lowest temperature of 100o C shows R0 at 0.116 kg/cm2, R1 at 0.070 kg/cm2, R3 of 0.046 kg/cm2. The results show a tendency of declining strength value as the soil farther away from center of heat induction. The experimental result from this model produces strength that can be used as a parameter of the foundation model on soft soil.

Study on Stressed Characteristic of Gridding Concrete Retaining Wall Used in Excavation of Soft-Soil Foundation Pit

2011 ◽  
Vol 243-249 ◽  
pp. 2266-2270
Author(s):  
Guang Zhu Zhou ◽  
Xu Wei ◽  
Chen Yu
Keyword(s):  
Retaining Wall ◽  
Soft Soil ◽  
Side Wall ◽  
Building Envelope ◽  
Front Wall ◽  
Soil Pressure ◽  
Back Wall ◽  
Foundation Pit ◽  
Partition Wall ◽  
Finite Element Software

As a new type of building envelope, Gcrw is mainly used for excavation of foundation pit. It can stand by itself without the help of bracing, especially in soft soil area. Its stressed characteristic hasn’t been known yet. By using advanced big finite element software Abaqus/Cae, a simulation was made on model of Gcrw under soil pressure when a foundation pit is dug, while the whole excavation is divided into three continuous independent excavation stages. The result shows that Gcrw is a rather good building envelope, Gcrw and soil in the gridding form an integral earth-retaining structure and keep balance under soil pressure before or behind the structure, and have little displacement in horizontal direction. It is like a gravity-type retaining wall in its entirety, but takes on an elastic characteristic. The soil pressure presents a linear change, but its value is less than the theoretical value of calculation. The front wall of Gcrw, like a sheet, is the main flexural construction element, which is subjected to the pressure from side wall of foundation pit and produce curve deformation. The back wall of Gcrw has little displacement and almost is built in the clay. The partition wall endures the effect of the tensile force, its horizontal deformation increases with the build-in depth’s increasing. The back wall and the partition wall play a very important role in dragging back the front wall, the role of them is similar to a pair of anchor tie. The soil in the gridding not only provides soil pressure, but also can fix the back wall, so it is seen as a part of Gcrw and in favor of the Gcrw’s anti-overturn.

Study of “Wave Type” Uneven Settlement and Reinforcing Method of Soft Clay Foundation

2011 ◽  
Vol 243-249 ◽  
pp. 2990-2996
Author(s):  
Li Qiang Sun ◽  
Shu Wang Yan ◽  
Hong Juan He ◽  
Yu Xu
Keyword(s):  
Soft Soil ◽  
Soft Clay ◽  
Traffic Load ◽  
Dominant Factor ◽  
Wave Type ◽  
The Road ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Preloading Method

The deformation is the dominant factor of the quality of the road constructed on the soft soil foundation. Tianjin DongJiang port is located on the hydraulic filled soil foundation which is improved by using vacuum preloading method. Roads in this area often suffer wave type asymmetry settlement, which serious affects the usage of the road and causes damage to both vehicles and human being. It is found that the initial wave asymmetry deformation of the road on very soft soil foundation usually exists and will be developing continuously under the traffic load. The mechanism of the wavy failure of the road is discussed by establishing a mechanical model. The method of using geogrids to reduce the asymmetry deformation is proposed, the reinforce effect is analyzed using finite element method.

Study on the Lateral Displacement of Super-Long Pile under a Asymmetrical Surcharge Load in Soft Clay

2014 ◽  
Vol 580-583 ◽  
pp. 733-737
Author(s):  
Qi Li ◽  
Xiao Li Lu
Keyword(s):  
Lateral Displacement ◽  
Soft Soil ◽  
Soft Clay ◽  
Three Dimensional ◽  
Influence Factors ◽  
Major Influence ◽  
Small Contribution ◽  
Practical Engineering ◽  
Surcharge Load ◽  
Building Load

The pile will have a large lateral displacement in soft soil under the role of heaped load. Based on Biot consolidation theory, combined with a certain highway project, a three-dimensional FEM model is established, the process that the soil lateral deformation under heaped load lead to the pile side displacement was simulated. On the ground of the former result, the influence factors for the displacement of pile top and the pile displacement field distribution are analysed. The results show that, the building load area, load grade and the distance from loading area to pile have a major influence on the pile side displacement. On the other hand, the load on pile top have a very small contribution for stability of anti side displacement. The buildings nearby the area of pile foundation should be given attention in practical engineering.

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