scholarly journals Study on the Behavior of Geosynthetic-Reinforced Pile-Supported Embankments in Soft Ground Improvement Solutions

2020 ◽  
Vol 55 (5) ◽  
Author(s):  
Nguyen Tuan Phuong ◽  
Nguyen Anh Tuan
Keyword(s):  
Load Transfer ◽  
Ground Improvement ◽  
Soft Soil ◽  
Soil Conditions ◽  
Soft Ground ◽  
Construction Time ◽  
Pile Cap ◽  
Pile Caps ◽  
Improvement Method ◽  
Foundation Type

Embankments on soft ground often encounter many problems such as settlement, slip, and deformation that exceed the permitted limit. In recent years, a new type of foundation called "geosynthetic-reinforced pile-supported embankments" has been used. Until now, although the behavior of this foundation type has been analyzed and certain results have been presented in literature, calculation methods do not allow geotechnical engineers to calculate the results accurately. This study builds up a field experiment model to investigate the impacts of arching effects in the sand buffer layer on pile heads to increase the load transfer on the pile caps. The results indicate that the stress distribution on the pile cap is 10.48 times higher than the stress on the surrounding soft soil. Hence, the ground improvement method using piles and geosynthetic reinforcement can be applied to roadbeds and industrial warehouses on soft soil conditions, which helps to shorten the construction time compared to other ground treatment methods such as preloading, vacuum pumps, wick drains, etc.

3D Numerical Modeling of Pile embankment performance on Soft Soil

2021 ◽  
Vol 9 (6) ◽  
pp. 715-722
Keyword(s):  
Numerical Study ◽  
Ground Improvement ◽  
Soft Soil ◽  
Ground Level ◽  
Soft Ground ◽  
Infrastructure Development ◽  
3D Numerical Modeling ◽  
Construction Time ◽  
Vertical Drains ◽  
Short Period

Embankments are often required in many civil engineering construction projects involving infrastructure development to elevate the ground level. Due to the limitation of land availability for infrastructure projects in many countries, a large number of projects are now being carried out on soft ground. However, embankment construction over soft ground is a challenging task due to several undesirable characteristics associated with soft soils such as local instability, inadequate bearing capacity and large settlements, which can occur over a long period of time. These problems can generally result in expensive remedial measures and long construction delays. The conventional soft ground improvement methods based on consolidation such as vertical drains and preloading are not suitable when projects have to be completed within a short period of time or the ground improvement has to be carried out in contaminated ground. In such situations, reinforced pile-supported embankments are increasingly used as an alternative construction method due to the shorter construction time required compared to consolidation based methods and due to the higher reliability of the method when the subsoil properties cannot be relied upon. . This paper presents a comprehensive numerical study carried out using the finite element method in order to investigate the performance of reinforced pile supported embankment. A detailed parametric study is presented inthree-dimensional conditions incorporating the full geometry of embankment system. The influence of pile embedded length, pile diameter, elastic modulus of piles, height of the embankment, construction rate of the embankment were investigated on the performance of the selected embankment.

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.

Research to build technological procedure for soft ground improvement using sea sand-cement-fly ash column

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 1-9
Author(s):  
Thinh Duc Ta ◽  
Phuc Dinh Hoang ◽  
Thang Anh Bui ◽  
Trang Huong Thi Ngo ◽  
Diu Thi Nguyen ◽  
...  
Keyword(s):  
Fly Ash ◽  
Load Capacity ◽  
Ground Improvement ◽  
Soft Soil ◽  
Soil Reinforcement ◽  
Soft Ground ◽  
Design Calculation ◽  
Sea Sand ◽  
Composite Ground ◽  
Soft Ground Improvement

Sea sand-cement-fly ash column technology for soft soil treatment is a new technology in the process of completing the theoretical basis, the experimental basis, and the construction of the ground treatment technological procedure. The paper presents the results of scientific research on design, calculation, construction, and acceptance of sea sand-cement-fly ash column. The scientific basis for the design of column is to consider the role of the column in composite ground, that is to use the column as soft ground improvement or soft soil reinforcement. The important parameters for the column design are: cement and fly ash content; column length; column diameter; number of columns; distance among columns; load capacity and settlement of composite ground. The sequence of steps of construction and acceptance of column includes: selection of construction equipment, preparation of construction sites, trial construction, official construction, evaluation of ground quality after treatment and preparation of document for acceptance.

scholarly journals Experimental application of optimal depth of PVDs determination under vacuum loading condition

2016 ◽  
Vol 19 (1) ◽  
pp. 116-121
Author(s):  
Nhat Dai Vo ◽  
Viet Hoang Quoc Lam ◽  
Tuan Minh Pham
Keyword(s):  
Loading Condition ◽  
Ground Improvement ◽  
Soft Soil ◽  
Small Error ◽  
Soft Ground ◽  
Optimal Depth ◽  
Geological Feature ◽  
Experimental Application ◽  
Technical Requirements ◽  
Soft Ground Improvement

Viet Nam is one of the country that has a very soft and complicated geological feature. Therefore, how to economize cost but satisfy the standard and technical requirements in designing by selecting an appropriate method in building especially projects constructed on soft ground is always needed to consider and research continuouslly. In this paper, a method how to determine the optimal depth of PVDs under vacuum loading condition for soft ground improvement is presented and applied to specific case in 861 provincial street, Ward Cai Be, Tien Giang District. The soft soil includes two layers with total 12m thick and is allowed to drain on the top and bottom faces (double drainage). The result shows that the optimal depth of PVDs is about 10,5m with the small error of 0,7%

Study on Artificial Island Ground Improvement Method and Effect

2014 ◽  
Vol 1030-1032 ◽  
pp. 1037-1040
Author(s):  
Jin Fang Hou ◽  
Ju Chen ◽  
Jian Yu
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Horizontal Displacement ◽  
Treatment Method ◽  
Surcharge Preloading ◽  
Porosity Ratio ◽  
Improvement Method ◽  
Consolidation Degree

The artificial island ground on an open sea is covered by thick soft soil. It must be improved before using. In accordance with a designing scheme, the ground treatment method is inserting drain boards on land and jointed dewatering surcharge preloading, the residual settlement is not more than 30cm after improvement and the average consolidation degree is more than 85%. In order to estimate ground improvement effect and construction safety, instruments are buried to monitor the whole ground improving processes. By monitoring settlement and pore water pressure, it is shown that the total ground settlement in construction is 2234mm, its final settlement is 2464mm, and consolidation degree and residual settlement respectively satisfy requirements. In ground improvement, horizontal displacement is small and construction is safe. Meanwhile, the results of soil properties and vane shear strength detection tests show the soft soil ground is greatly reduced in water content and porosity ratio, and improved in strength. It is named that the ground improvement method is reasonable and reaches expected effect.

Field Study of Improvement Mechanism of Geogrid-Reinforced and Pile-Supported Embankment

2014 ◽  
Vol 587-589 ◽  
pp. 928-933 ◽  
Author(s):  
Feng Lian ◽  
Zhi Liu ◽  
Jie Xu ◽  
Qiang Wang ◽  
Xian Hu Hu ◽  
...  
Keyword(s):  
Load Transfer ◽  
Soft Soil ◽  
Composite Foundation ◽  
Replacement Ratio ◽  
Floating Pile ◽  
Pile Cap ◽  
Soil Arch ◽  
Better Than ◽  
End Bearing Pile ◽  
Pile Supported Embankment

Two experimental areas in a highway soft soil ground treatment project in Guangdong Province were designed to investigate the improvement mechanism of geogrid-reinforced and pile-supported embankment(GRPS).The experimental results showed: In End-bearing Pile Area,the differential settlement between pile and soil was bigger than that of Floating Pile Area,so the bearing capacity of soil was exerted to a certain extent in Floating Pile Area. The bearing efficacy of soil below the pile cap was little, so the replacement ratio of composite foundation could be calculated according to the pile cap dimension. The load transfer efficacy of the geogrid was better than that of the soil arch. Five kinds of methods were used to evaluate the soil arch in the fill and it was indicated that the results calculated by the BS8006 method and Carlsson method was close to the experimental data which was smaller than results calculated by Hewlett method and Terzaghi method, bigger than Guido method. Through the analysis of the pile-soil stress ratio, the improvement mechanism of the two types of GRPS were revealed.

Consolidation in Soft Soil – Case Study on Prefabricated Vertical Drains (PVDs)

2021 ◽  
Vol 15 (1) ◽  
pp. 310-319
Author(s):  
Nadarasa Kuganeswaran ◽  
Afikah Rahim ◽  
Nazri Ali
Keyword(s):  
Ground Improvement ◽  
Soft Soil ◽  
3D Analysis ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain ◽  
Improvement Method ◽  
Plaxis 3D

Background: Constructing on soft ground is one of the challenges of geotechnical engineering. The unpredictable behaviour and characteristics of soft soil can cause much damage resulting in high maintenance costs in the post-construction phase. Objective: The purpose of this study is to analyse the consolidation process and ground improvement method using surcharge and a prefabricated vertical drain by measuring the accuracy of the prediction settlement value with the actual site settlement results. Methods: An effective ground improvement method is the application of a surcharge and prefabricated vertical drains (PVDs). Various methods can be used to predict the settlement effectively, one such method being PLAXIS 3D simulation. A case study on ground improvement works was selected for this research, where PVDs were constructed and implemented at the site. A few undisturbed samples were collected from the site to generate the parameters based on the lab test conducted in the simulation process. This parameter was carefully studied and representing the principal input for the 3D model, which is generated and represents the actual ground improvement method for the selected case study. The analysis was performed using a borehole and soft soil model to generate the diagram. The prediction settlement value was generated from the PLAXIS 3D analysis as the baseline comparing to the actual results. The factors that influence the settlement value, such as the length and spacing of the prefabricated vertical drain, construction method, and soil characteristics, are also discussed. Results: A predicted settlement of 2553 mm was generated by the simulation, while the actual settlement outcome at the site was 2096 mm, a difference of 457 mm, and a prediction accuracy of 82.1%. Conclusion: The study found that the combination of surcharge and prefabricated vertical drain in the ground improvement worked well. Also, discussed were the factors that influenced the accuracy of the prediction and the site results.

INNOVATIVE SOFT SOIL IMPROVEMENT BY VACUUM DE-WATERING AND DYNAMIC COMPACTION

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Tuncer B. Edil
Keyword(s):  
Large Scale ◽  
Ground Improvement ◽  
Soft Soil ◽  
High Vacuum ◽  
Cohesive Soil ◽  
Soil Improvement ◽  
Economic Benefits ◽  
Dynamic Compaction ◽  
Environmental Benefits ◽  
Improvement Method

Recently, an innovative soft soil improvement method was advanced in China by integrating and modifying vacuum consolidation and dynamic compaction ground improvement techniques in an intelligent and controlled manner. This innovative soft soil improvement method is referred to as “High Vacuum Densification Method (HVDM)” to reflect its combined use of vacuum de-watering and dynamic compaction techniques in cycles. Over the past ten years, this innovative soft soil improvement technique has been successfully used in China and Asia for numerous large-scale soft soil improvement projects, from which enormous time and cost savings have been achieved. In this presentation, the working principles of the HVDM will be described. A discussion of the range of fine-grained, cohesive soil properties that would make them ideal for applying HVDM as an efficient ground improvement method will be discussed. The economic benefits and environmental benefits of HVDM are elucidated.

Sign in / Sign up

Export Citation Format

Share Document