scholarly journals Evaluation of SHANSEP parameters for soft clay in HCM City

2019 ◽  
Vol 20 (K9) ◽  
pp. 31-37
Author(s):  
Kieu Le Thuy Chung ◽  
Phan Thi San Ha ◽  
Le Minh Son
Keyword(s):  
Ground Improvement ◽  
Urban Expansion ◽  
Soft Clay ◽  
Ho Chi Minh City ◽  
Coefficient Of Determination ◽  
Triaxial Tests ◽  
Soft Ground ◽  
Test Results ◽  
Rapid Pace ◽  
Soft Ground Improvement

Located in a flat plain with an extensive covering of very soft clay, Ho Chi Minh city is still in its urbanization and urban expansion with an inevitable development in construction at rapid pace. SHANSEP parameters for soft clay in HCM City will be helpful for geotechnical engineers in quantifying the behavior of soft clay and proposing suitable solutions for soft ground improvement. This paper presents the results of 100 CIUC triaxial tests on 20 clay samples belonging to two different groups of soft clay (taken in Binh Thanh and Nha Be districts) tested with 5 different modes of OCRs, i.e. 1, 1.5, 2, 4, and 6. The test results are analyzed to obtain SHANSEP models with really high coefficient of determination (R2 ≈ 1).

A precompression method of soft ground improvement using dewatering

1991 ◽  
Vol 7 (1) ◽  
pp. 651-658
Author(s):  
H. Kotera ◽  
T. Sakemi ◽  
T. Matsui
Keyword(s):  
Water Pressure ◽  
Ground Improvement ◽  
Soft Clay ◽  
Soil Improvement ◽  
Tokyo Bay ◽  
Soft Ground ◽  
Improvement Project ◽  
Vertical Drains ◽  
Clay Ground ◽  
Soft Ground Improvement

AbstractThe background and geology of the Tokyo Bay area of Japan, and recent soil improvement methods used in Japan are described. The vertical drain method has frequently been used to improve thick quarternary deposits in this area. This paper describes a case history of a dewatering method in combination with the vertical drains and preloading in a major soft ground improvement project in the Urayasu area of the Tokyo Bay. The dewatering method is a vacuum consolidation method, which is tentatively applied to the soft clay ground.In the combined dewatering method, the waterhead in a vertical sand drain is lowered by pumping the water from a sand layer within or below a soft clayey layer using deep wells. The dewatering applies negative water pressure to the soft clayey layer, promoting its consolidation.The authors confirm the consolidation effect of the dewatering and establish the applicability of the combined dewatering method to the soft clay ground.It is concluded that the dewatering method described significantly increases the shear strength and the consolidation yield stress of the soft clayey layer.

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.

A Change of Undrain Shear Strength of Soft Ground during Consolidation Process

2014 ◽  
Vol 513-517 ◽  
pp. 269-272
Author(s):  
Yeong Mog Park ◽  
Ik Joo Um ◽  
Norihiko Miura ◽  
Seung Cheol Baek
Keyword(s):  
Shear Strength ◽  
Soft Clay ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Test Results ◽  
Exponential Equation ◽  
Consolidation Process ◽  
Degree Of Consolidation ◽  
Clay Ground ◽  
Strength Increment

The purpose of this study is to investigate the undrain shear strength increment during consolidation process of soft clayey soils. Thirty kinds of laboratory triaxial tests have been performed using undisturbed and remolded Ariake clay samples with different degree of consolidation and 5 kinds of confining pressure. Test results show that well known linear equation proposed by Yamanouchi et al.(1982) is overestimated the strength of undisturbed soft clay ground in the process of consolidation. A new simple and reasonable exponential equation proposed in this paper.

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%

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