Experimental Research of Soft Soil Ground Treatment in Yangpu Port by Static-Dynamic Drainage Consolidation

2013 ◽  
Vol 353-356 ◽  
pp. 203-207
Author(s):  
Yong Kang Yang ◽  
Wu Yang ◽  
Chun Yan Feng
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Drainage System ◽  
Physical And Mechanical Properties ◽  
High Water ◽  
Surface Settlement ◽  
High Water Content ◽  
Engineering Practice ◽  
Ground Treatment

Yangpu Port has inhomogeneous soft soil with the properties of high water content, high void ratio, high compressibility and low shear strength. Based on soft soil ground treatment engineering practice, the geological characteristics are summarized, the ground treatment methods are comparatively analyzed, static-dynamic drainage consolidation method is chosen to treat the soft soil ground, the reinforcing mechanism of vertical and horizontal drainage system are discussed, the design of drainage system, preloading and dynamic consolidation are researched and the surface settlement monitoring, pore water pressure monitoring, side piling displacement monitoring, laboratory soil test and plate loading tests are carried out. The results show that average surface settlement is 1170.8 mm, the physical and mechanical properties of soft soil are improved and the characteristic value of foundation bearing capacity is greater than 120kPa.

scholarly journals METODE VACUUM CONSOLIDATION DENGAN PRELOADING UNTUK MEMPERCEPAT KONSOLIDASI TANAH PADA PERUMAHAN DI TANGERANG

2021 ◽  
Vol 4 (1) ◽  
pp. 171
Author(s):  
Jason Sastilaya ◽  
Gregorius Sandjaja Sentosa
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Drainage System ◽  
Soil Condition ◽  
Soil Improvement ◽  
Soil Conditions ◽  
Soil Plasticity ◽  
Calculation Results ◽  
Long Time

The expansion of housing in big cities cannot be denied given the rapid population growth in Indonesia. One of the areas that is currently expanding housing is Kosambi City, Tangerang. Soil conditions in Kosambi City are soft soil with high moisture content and soil plasticity, low permeability and soil bearing capacity, and high pore water pressure. This soft soil condition makes the consolidation decline take a very long time. To overcome the problem of the length of time for this consolidation settlement, it is necessary to improve the land. Soil improvement is being carried out, namely the method of vaccum consolidation with preloading. The combination of these methods is carried out by installing a vertical drainage system in the form of prefabricated fabricated drain (PVD) in soft soil, then the initial load is given in the form of preloading on the soil. The calculation results show that the amount of consolidation reduction that occurs when clay soil is loaded with a stockpile of 1.2 m high, a water surcharge of 1.3 m and a vaccum load is 0.3929 m and 0.6968 m for 85 years. The combined method of preloading and PVD is proven to be able to accelerate the time of consolidation, where Preloading and PVD are installed in a triangle pattern between 0.80 m to a depth of 12 m, capable of achieving a consolidation degree of 90% within 8 weeksPerluasan perumahan di kota besar tentu tidak dapat dipungkiri mengingat pesatnya pertumbuhan penduduk di Indonesia. Salah satu daerah yang sedang dilakukan perluasan perumahan yaitu Kosambi City, Tangerang. Kondisi tanah di Kosambi City merupakan tanah lunak dengan kadar air dan plastisitas tanah yang tinggi, permeabilitas dan daya dukung tanah yang rendah, serta tingginya tekanan air pori. Kondisi tanah lunak ini membuat penurunan konsolidasi membutuhkan waktu yang sangat lama. Untuk mengatasi masalah lamanya waktu penurunan konsolidasi ini, perlu dilakukan perbaikan tanah. Perbaikan tanah yang dilakukan yaitu metode vaccum consolidation dengan preloading. Kombinasi pada metode ini dilakukan dengan cara memasang sistem drainase vertikal berupa prefabricated fabricated drain (PVD) di dalam tanah lunak, kemudian diberikan beban awal yaitu berupa timbunan (preloading) pada tanah tersebut. Hasil perhitungan menunjukkan besar penurunan konsolidasi yang terjadi jika tanah lempung dibebani dengan timbunan setinggi 1,2 m, water surcharge setinggi 1,3 m dan beban vaccum  adalah 0,3929 m dan 0,6968 m selama 85 tahun. Metode kombinasi preloading dan PVD terbukti mampu mempercepat waktu konsolidasi, dimana Preloading dan PVD dipasang dengan pola segitiga berjarak 0,80 m hingga kedalaman 12 m, mampu mencapai derajat konsolidasi 90% dalam waktu 8 minggu. 

scholarly journals Field Study on the Waterstop of the Rodin Jet Pile Method in a Water-Rich Sandy Gravel Stratum

2019 ◽  
Vol 9 (8) ◽  
pp. 1709
Author(s):  
Chengli Guan ◽  
Yuyou Yang
Keyword(s):  
High Pressure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Tests ◽  
High Water ◽  
High Water Content ◽  
Sandy Gravel ◽  
Ultra High Pressure ◽  
Jet Grouting ◽  
Silty Soils

Due to the increasing depths of underground urban construction, the surrounding environment and hydrogeological conditions are becoming increasingly complex, and conventional high-pressure rotary jet grouting has become unable to meet construction needs. At present, Rodin jet pile (RJP) ultra-high-pressure rotary jet grouting has been widely used as a grouting reinforcement method for deep and large foundations in silty soils, fine sands and clay strata; however, there have been no successful applications in a sandy gravel stratum with high water content (namely, water-rich sandy gravel stratum). Therefore, this paper uses the ventilating shaft in a section of the Beijing Metro as the construction background to carry out field tests on the RJP ultra-high-pressure rotary jet grouting method and waterstop in a water-rich sandy gravel stratum. Through a series of experiments monitoring the formation deformation and pore water pressure and exposing the pile diameter, pile occlusion, pile strength, and permeability of the test pile construction process, it is believed that, for the RJP ultra-high-pressure construction method in a water-rich sandy gravel stratum, reliable jet solidification can occur, the joint between jets can be achieved, the solid strength can reach 10 MPa or higher, and the permeability coefficient can reach 10−8 cm/s. Therefore, RJP ultra-high-pressure rotary jet grouting can be applied as a waterstop method in water-rich sandy gravel stratum.

scholarly journals Stability and Consolidation of Sediment Tailings Incorporating Unsaturated Soil Mechanics

Fluids ◽  
2021 ◽  
Vol 6 (12) ◽  
pp. 423
Author(s):  
Alfrendo Satyanaga ◽  
Martin Wijaya ◽  
Qian Zhai ◽  
Sung-Woo Moon ◽  
Jaan Pu ◽  
...  
Keyword(s):  
Unsaturated Soil ◽  
Pore Water Pressure ◽  
Soil Mechanics ◽  
Water Pressure ◽  
High Water ◽  
Degree Of Saturation ◽  
High Water Content ◽  
Consolidation Process ◽  
Time Required ◽  
Unsaturated Zones

Tailing dams are commonly used to safely store tailings without damaging the environment. Sand tailings (also called Sediment tailings) usually have a high water content and hence undergo consolidation during their placement. As the sediment tailings are usually placed above the ground water level, the degree of saturation and permeability of the sediment tailing is associated with the unsaturated condition due to the presence of negative pore-water pressure or suction. Current practices normally focus on the analyses saturated conditions. However, this consolidation process requires the flow of water between saturated and unsaturated zones to be considered. The objective of this study is to investigate the stability and consolidation of sediment tailings for the construction of road pillars considering the water flow between saturated and unsaturated zones. The scope of this study includes the unsaturated laboratory testing of sediments and numerical analyses of the road pillar. The results show that the analyses based on saturated conditions overestimate the time required to achieve a 90% degree of consolidation. The incorporation of the unsaturated soil properties is able to optimize the design of slopes for road pillars into steeper slope angles.

Research on Surface-Layer Improvement Technology for Dredger Fill by Vacuum Preloading

2012 ◽  
Vol 256-259 ◽  
pp. 1703-1706
Author(s):  
Yan Hua Yang ◽  
Fu Quan Ji ◽  
Zhao Yang
Keyword(s):  
Large Scale ◽  
Soft Soil ◽  
Soft Clay ◽  
Drainage System ◽  
High Water ◽  
Soil Improvement ◽  
High Water Content ◽  
Construction Technology ◽  
Vacuum Preloading ◽  
Reclaimed Land

The surface-layers have very high water content and low bearing capacity, so far to be the very soft clay foundation, which come from the reclaimed land in project of reclamation. It is difficult to improve the very soft clay foundation by traditional vacuum preloading. A new method named surface soft soil improvement is presented in this paper, which can make the soft clay foundation to be improved in preliminary. Once forming the hard coat layer, the foundation may reach the needs of further construction. In the construction technology, the horizontal filter pipe net is used to instead of the sand bedding course. By laying of woven cloth and non-woven geotextile over the surface of reclaimed silt, installing PVDs by manpower becomes possible. Besides, the vertical PVDs all are connected with the horizontal filter pipe net directly, that makes a whole spatial drainage system. The loss of the degree of vacuum is decreased, and the improvement is increased. Thus, this construction technology is as a reference to the large scale engineering construction and similar projects.

Research on Mechanism of Consolidating the Saturated Soft Clay with the Application of Pile-Supported Composite Foundation

2012 ◽  
Vol 594-597 ◽  
pp. 370-375
Author(s):  
Zhao Hua Zhang
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soft Clay ◽  
Drainage System ◽  
Single Layer ◽  
Composite Foundation ◽  
Critical Height ◽  
The Stability ◽  
Saturated Soft Clay

In order to reduce both uneven settlements and construction duration, researches on pile-supported composite foundation of highway were carried out. When the groundfill is higher than the critical height（1.35 times space between piles）, a complete geostatic arch is formed in the pile-supported composite foundation, which could significantly reduce the uneven settlement. Grids installed at the bottom of embankment could markedly reduce the side displacement and increase the stability of embankment, multilayer grids with layout of loose on the top and dense at the bottom prefer to single layer grids. Plastic drainage board makes up well-functioned drainage system, which can shorten the dispersal time of pore water pressure and accelerate the consolidation of soft soil to shorten the construction duration.

Initiation Analysis of an Irrigation-Induced Loess Landslide

2012 ◽  
Vol 170-173 ◽  
pp. 574-580 ◽  
Author(s):  
Hong Jie Li ◽  
Yan Li Jin
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
High Water ◽  
Underground Water ◽  
Shanxi Province ◽  
Triaxial Tests ◽  
High Water Content ◽  
Compression Tests ◽  
Loess Landslide ◽  
Water Level Rise

Underground water level rise because of irrigation has induced a lot of loess landslides in South Jingyang Plateau located in Shanxi Province, PR China. This paper presents a detailed initiation analysis of the landslides through field investigations, a series of GDS triaxial tests composed of isotropically and anisotropically consolidated undrained (ICU/ACU) compression tests and constant-shear-drained (CQD) triaxial tests for undisturbed saturated loess and numerical modeling. The tests show that the contractive failure will cause excess pore water pressure that cannot be dissipated instantly, and will result in the decrease of the shearing resistance. Shear deformation during failure moves the soil toward the critical state rapidly and make the loess completely in liquefactive condition. Therefore, the slope is prone to rapid and long run-out flow slide after failure under the action of gravity because of its high water content.

The effect of pore-water pressure on NATM tunnel linings in decomposed granite soil

2005 ◽  
Vol 42 (6) ◽  
pp. 1585-1599 ◽  
Author(s):  
J H Shin ◽  
D M Potts ◽  
L Zdravkovic
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Drainage System ◽  
Tunnel Lining ◽  
Natm Tunnel ◽  
Decomposed Granite ◽  
Secondary Lining ◽  
Granite Soil ◽  
Functional Components

Tunnelling in a water bearing soil often produces a long-term interaction between the tunnel lining and the surrounding soil. With respect to lining design, infiltration and external pore-water pressures are often one of the most important factors to be considered. Development of pore-water pressure may accelerate leakage and cause deterioration of the lining. This can be particularly troublesome to structural and functional components of the tunnel and can often lead to structural failure. However, as a result of the complicated hydraulic boundary conditions and the long times often required for pore pressure equilibration, research on this subject is scarce. Consequently, most design approaches deal with the effects of pore-water pressure on the tunnel lining in a qualitative manner. In this paper, the development of pore-water pressure and its potential effects on the tunnel lining are investigated using the finite element method. In particular, the deterioration of a drainage system caused by clogging is considered. It is shown that the development of pore-water pressure on the lining is dependent on the lining permeability and the deterioration of the drainage system, particularly for a tunnel with both a primary and a secondary lining. The magnitude of pore-water pressure on a new Austrian tunnelling method (NATM) tunnel constructed in decomposed granite soil and the effect of tunnel shape are investigated. Design curves for estimating pore-water pressure loads on a secondary lining are proposed.Key words: numerical analysis, tunnel lining, decomposed granite.

Geosynthetic Encased Column: comparison between numerical and experimental results

2021 ◽  
Vol 44 (4) ◽  
pp. 1-12
Author(s):  
Nima Alkhorshid ◽  
Gregório Araújo ◽  
Ennio Palmeira
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Experimental Tests ◽  
High Permeability ◽  
Soft Soils ◽  
Column Comparison ◽  
Surrounding Soil ◽  
Granular Column

The use of granular column is one of the ground improvement methods used for soft soils. This method improves the foundation soils mechanical properties by displacing the soft soil with the compacted granular columns. The columns have high permeability that can accelerate the excess pore water pressure produced in soft soils and increase the undrained shear strength. When it comes to very soft soils, the use of granular columns is not of interest since these soils present no significant confinement to the columns. Here comes the encased columns that receive the confinement from the encasement materials. In this study, the influence of the column installation method on the surrounding soil and the encasement effect on the granular column performance were investigated using numerical analyses and experimental tests. The results show that numerical simulations can reasonably predict the behavior of both the encased column and the surrounding soil.

scholarly journals Effects of High Plasticity and Expansive Clay Stabilization with Lime on UCS Testing in Several Conditions

2021 ◽  
Vol 1000 (1000) ◽  
Author(s):  
Soewignjo Agus Nugroho ◽  
Gunawan Wibisono ◽  
Andarsin Ongko ◽  
Avrilly Zesthree Mauliza
Keyword(s):  
Soil Stabilization ◽  
Soft Soil ◽  
Fine Powder ◽  
High Water ◽  
Liquid Limit ◽  
Clay Soils ◽  
High Water Content ◽  
High Plasticity ◽  
Expansive Clay ◽  
Limit Value

Clay is a cohesive and very soft soil if it has high water content. To overcome this problem, clay soils with high plasticity need to be stabilized. The method of soil stabilization with lime is an alternative effort to improve soil that does not meet the standards. Lime reacts with groundwater so that it changes the property of the soil, reducing the stickiness and softness of the soil. Lime also functions to solidify (stabilize) and stabilize (stabilize) soil in the form of fine powder consisting of metals and inorganic mineral composition. This study aims to determine the effect of clay soils when carried out stabilization by using a limestone additive which varies in levels of mixture. The results showed that lime effective for the stabilization high plasticity and expansive clay by increasing the compressive strength value of UCS with lime content of 10% under curing conditions in 28 days and unsoaked by 319%, the liquid limit value reduced by 6% and the plastic limit value increased by 46%.

scholarly journals Perbandingan Pengujian Konsolidasi Menggunakan Alat Rowe Cell dan Oedometer pada Tanah Lanau Lunak

2020 ◽  
Vol 22 (2) ◽  
pp. 149-155
Author(s):  
Iskandar ◽  
Rabiya
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soil Samples ◽  
Soil Parameters ◽  
Soil Consolidation ◽  
Test Results ◽  
Soft Soils ◽  
Better Than ◽  
Rowe Cell

Soil consolidation testing using an oedometer and rowe cell. Oedometers are often used on clay and soft soils. However, in the development of the rowe cell device, the results of lowering soft soil were better than the oedometer. The advantage of this rowe cell is that it can determine the saturation value of the soil samples tested. The rowe cell tester can measure the pore water pressure at the beginning and end of each consolidation stage. This rowe cell can provide suitable settlement for soft soils. This consolidation test to obtain soil parameters such as Cv and Cc by using the rowe cell tool. After that, from the test results, the two tools were compared.

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