Design charts for vertical drains considering construction time

2001 ◽  
Vol 38 (5) ◽  
pp. 1142-1148 ◽  
Author(s):  
Guofu Zhu ◽  
Jian-Hua Yin
Keyword(s):  
Design Procedure ◽  
Technical Note ◽  
Engineering Properties ◽  
Construction Time ◽  
Vertical Drains ◽  
Vertical Drain ◽  
Design Charts ◽  
Degree Of Consolidation ◽  
Free Strain ◽  
Consolidation Time

This technical note presents design charts for use in determining the required drain spacing explicitly using free strain assumption. The influence of time-dependent loading is incorporated in the design charts. The design procedure is also described. When the radius of vertical drain, required degree of consolidation, time available, and pertinent geotechnical engineering properties of a soil are given, the charts can be used to design a vertical drain system without unnecessary trial and error processes.Key words: consolidation, vertical drain, design charts, time dependence, drainage.

scholarly journals ANALISIS PENGGUNAAN PREFABRICATED VERTICAL DRAINS (PVD) PADA TANAH LEMPUNG LUNAK YANG TERDAPAT LAPISAN LENSA

2020 ◽  
Vol 3 (1) ◽  
pp. 119
Author(s):  
Andreyan Prasetio ◽  
Aniek Prihatiningsih
Keyword(s):  
Soft Soil ◽  
Soil Improvement ◽  
Cohesive Soils ◽  
Consolidation Process ◽  
Prefabricated Vertical Drains ◽  
Soil Layers ◽  
Vertical Drains ◽  
Vertical Drain ◽  
Installation Depth ◽  
Consolidation Time

Problem that often occurs in soft cohesive soils is settlement caused by consolidation process. If  construction activities doing when the soils has not been consolidated, settlement can occur. To accelerate  the consolidation process, soil improvement are usually do, one method of soil improvement to accelarate the consolidation process is vertical drain using prefabricated vertical drains (PVD). The soft soil layers in the field are not always continuous, sometimes found soft soil layers that have a lens layer. In this study, will discuss about the settlement and consolidation time of soft  soil layers that have a lens layer which has been improved by PVD with 1 meter distance. Infrastructure that stand on a location that is installed by PVD is taxiway and loading by Airbus A380 aircraft of 18,22ton/m2. Analysis using the 1 dimensional consolidation theory of Terzaghi. For PVD installation to a depth of 50 meters, preloading settlement of 234,80 cm with a consolidation time of  2260 days for the square pattern PVD and 1918 days for triangle pattern PVD. Post loading settlement for PVD installation depth of 50 meters by 2,50 cm. AbstrakMasalah yang sering terjadi pada tanah kohesif dan lunak adalah penurunan yang disebabkan proses konsolidasi. Penurunan dapat menyebabkan keretakan pada struktur konstruksi yang berada di atasnya. Jika suatu kegiatan konstruksi dilakukan saat tanah belum terkonsolidasi, maka konstruksi tersebut dapat mengalami penurunan.. Untuk mempercepat proses konsolidasi biasanya dilakukan perbaikan tanah, salah satu metode perbaikan tanah untuk mempercepat proses konsolidasi yaitu vertical drain dengan menggunakan prefabricated vertical drains (PVD). Lapisan tanah lunak yang terdapat di lapangan tidak selalu kontinu, terkadang ditemukan lapisan tanah lunak yang terdapat lapisan lensa. Pada penelitian ini, penulis akan membahas mengenai waktu konsolidasi yang dibutuhkan oleh lapisan tanah kohesif dan lunak yang terdapat lapisan lensa yang telah diperbaiki dengan menggunakan PVD berjarak 1 meter. Infrastruktur yang berdiri di atas lokasi yang dipasang PVD berupa taxiway dengan beban berupa pesawat Airbus A380 sebesar 18,22 ton/m2. Analisis dilakukan menggunakan teori konsolidasi 1 dimensi Terzaghi. Untuk pemasangan PVD hingga kedalaman 50 meter diperoleh penurunan pra pembebanan sebesar 234,80 cm dengan waktu konsolidasi selama 2260 hari untuk pemasangan PVD pola persegi dan selama 1918 hari untuk pola segitiga . Penurunan pasca pembebanan untuk pemasangan PVD hingga kedalaman 50 meter sebesar 2,5 cm.

scholarly journals Application of Prefabricated Vertical Drain (PVD) for Basic Soil Stabilization in the Railway Double Track Construction Project at Km 437 + 300 to Km 438 + 500 Gombong, Kebumen

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Ayu Prativi ◽  
Septiana Widi Astuti ◽  
Ahmad Ependi
Keyword(s):  
Land Subsidence ◽  
Soil Stabilization ◽  
Construction Project ◽  
Development Project ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain ◽  
Degree Of Consolidation ◽  
Double Track ◽  
Consolidation Time

The subgrade in the railway double track development project in KM 437 + 300 to KM 438 + 500 Gombong, Kebumen is soft land (N-SPT <15) so that it requires efforts to improve the land to avoid land subsidence exceeding the allowable land subsidence, which is equal to 20cm In this research, an effort to repair subgrade uses Prefabricated Vertical Drain (PVD) to accelerate the process of soil congestion due to the load of the railroad pile, the burden of railroad construction, and the burden of the passing railroad. Compression analysis results show that the subgrade will experience a land subsidence of 0.524m. The natural consolidation time needed to achieve a 90% degree of consolidation is 268.9 years. Meanwhile, the time of consolidation to reach a degree of consolidation of 90% using PVD spaced 0.8 m with a triangle and quadrilateral pattern is for 15 weeks and 18 weeks. Planting PVD in both patterns is as deep as 24 m

scholarly journals Analytical solutions and design curves for vacuum-assisted consolidation with both vertical and horizontal drainage

2007 ◽  
Vol 44 (2) ◽  
pp. 188-200 ◽  
Author(s):  
Cholachat Rujikiatkamjorn ◽  
Buddhima Indraratna
Keyword(s):  
Analytical Modeling ◽  
Excess Pore Pressure ◽  
Soil Consolidation ◽  
Factor Analyses ◽  
Soil Permeability ◽  
Vacuum Preloading ◽  
Vertical Drains ◽  
Design Charts ◽  
Horizontal Drainage ◽  
Degree Of Consolidation

A system of vertical drains combined with vacuum preloading is an effective method for promoting radial flow to accelerate soil consolidation. This study presents the analytical modeling of the consolidation of vertical drains incorporating vacuum preloading considering both vertical and horizontal drainage. The effects of a number of dimensionless parameters involving the drain length, soil permeability, and vacuum pressure are examined through average excess pore pressure, degree of consolidation, associated settlement, and time factor analyses. An analysis of selected case histories compliments the use of the proposed solutions. Design charts are also presented for practical use.Key words: analytical solution, consolidation, design charts, vertical drains.

Combined effects of reinforcement and prefabricated vertical drains on embankment performance

2001 ◽  
Vol 38 (6) ◽  
pp. 1266-1282 ◽  
Author(s):  
Allen Lunzhu Li ◽  
R Kerry Rowe
Keyword(s):  
Shear Strength ◽  
Design Procedure ◽  
Strength Gain ◽  
Foundation Soil ◽  
Simple Method ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Prefabricated Vertical Drain ◽  
Degree Of Consolidation ◽  
Embankment Stability

The behaviour of geosynthetic-reinforced embankments constructed over soft cohesive soils installed with prefabricated vertical drains (PVDs) is investigated by numerically examining an embankment constructed over different foundation soils. The partial consolidation during embankment construction, the consequent shear strength gain of the foundation soil, and the effect of the use of reinforcement on the mobilization of shear strength are examined. It is shown that the combined use of reinforcement and PVDs can significantly increase embankment stability and potentially allow the rapid construction of higher embankments than could be achieved with either method of soil improvement alone. Construction rate and spacing of PVDs can significantly affect the degree of consolidation at the end of construction and the stability of the embankment. For the situation examined, the effect of well resistance of typical vertical drains is insignificant. A relatively simple method for calculating the degree of consolidation and the strength gain of the foundation soil during construction is evaluated based on finite element results and is shown to be reasonably conservative. A design procedure is proposed to combine the design of reinforcement and PVDs.Key words: soft clay, prefabricated vertical drain, reinforcement, embankment stability, consolidation, strength gain.

Effectiveness of partially penetrating vertical drains under a combined surcharge and vacuum preloading

2011 ◽  
Vol 48 (6) ◽  
pp. 970-983 ◽  
Author(s):  
Xueyu Geng ◽  
Buddhima Indraratna ◽  
Cholachat Rujikiatkamjorn
Keyword(s):  
Analytical Solutions ◽  
Soft Clay ◽  
Three Dimensional ◽  
Vacuum Pressure ◽  
Vacuum Preloading ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Vertical Drain ◽  
Degree Of Consolidation ◽  
Pressure Suction

This paper considers the consolidation of a layer of clay in which partially penetrating prefabricated vertical drains (PVDs) are used in conjunction with a combined surcharge and vacuum preloading. Analytical solutions for partially penetrating PVDs are derived by considering vacuum pressure (suction), time-dependent embankment surcharge, well resistance, and smear zone. Three-dimensional seepage with a virtual vertical drain is assumed to reflect real seepage into the soil beneath the tip of a PVD. Analytical solutions were then used to examine the length of the vertical drain and vacuum pressure on soft clay to determine the consolidation time and degree of consolidation, associated settlement, and distribution of suction along the drain. The proposed solutions are then employed to analyse a case history. Finally, an appropriate PVD length in relation to clay thickness and drain spacing is recommended for various loading patterns.

scholarly journals Design Charts for Axially Loaded Single Pile Action

2019 ◽  
Vol 5 (4) ◽  
pp. 922-939 ◽  
Author(s):  
Anis Abdul Khuder Mohamad Ali ◽  
Jaffar Ahemd Kadim ◽  
Ali Hashim Mohamad
Keyword(s):  
Clay Soil ◽  
Skin Resistance ◽  
Soft Clay ◽  
Single Layer ◽  
Load Test ◽  
Engineering Properties ◽  
Single Pile ◽  
Dense Sand ◽  
Design Charts ◽  
Pile Length

The objective of this article is to generating the design charts deals with the axially ultimate capacity of single pile action by relating the soil and pile engineering properties with the pile capacity components. The soil and are connected together by the interface finite element along pile side an on its remote end.  The analysis was carried out using ABAQUS software to find the nonlinear solution of the problem. Both pile and soil were modeled with three-dimensional brick elements. The software program is verified against field load-test measurements to verify its efficiency accuracy. The concrete bored piles are used with different lengths and pile diameter is taken equals to 0.6 m. The piles were installed into a single layer of sand soil with angles of internal friction (20° t0 40°) and into a single layer of clay soil with Cohesion (24 to 96) kPa.  The getting results showed that for all cases study the total compression resistance is increased as pile length increased for the same property of soil, also illustrious that the total resistance of same pile length and diameter increased as the soil strength increasing. In addition, the same results were obtained for the end bearing resistance, skin resistance and tension capacity. Design charts were constructed between different types of soil resistance ratio and the pile length/diameter ratio (L/D) for all cases of study. One of improvement found from these curves that it is cheaply using piles of larger diameter than increasing their lengths for dense sand and to increasing piles lengths for loose sand. Moreover, it is inexpensively using piles of larger length in soft clay soil than increasing their diameter and piles of larger diameter in firm and stiff clay soils than increasing their length.

Solution charts for the consolidation of double soil layers

2005 ◽  
Vol 42 (3) ◽  
pp. 949-956 ◽  
Author(s):  
Guofu Zhu ◽  
Jian-Hua Yin
Keyword(s):  
Solution Procedure ◽  
Technical Note ◽  
Average Degree ◽  
Soil Layers ◽  
Consolidation Settlement ◽  
Degree Of Consolidation ◽  
Independent Parameters

This technical note presents solution charts for determining the average degree of consolidation of double soil layers for both one-way and two-way drainage. The influence of two newly introduced independent parameters on the average degree of consolidation is examined. The solution procedure is described clearly. When the compressibility, permeability, and thickness of the material making up each layer are given, the charts can be used to obtain the average degree of consolidation of the double soil layers for consolidation settlement calculations.Key words: consolidation, double soil layers, solution charts, drainage, settlement, soil.

scholarly journals Engineering Properties of Concrete by Partial Replacement of Cement with Aluminium Slag and Fine Aggregate with Foundary Sand

2019 ◽  
Vol 8 (6) ◽  
pp. 3870-3874
Keyword(s):  
Waste Product ◽  
Engineering Properties ◽  
Partial Replacement ◽  
Plastic State ◽  
Fine Aggregate ◽  
Structural Elements ◽  
Construction Time ◽  
Conventional Concrete ◽  
Waste Products ◽  
The Matrix

A self-compacting concrete (s.c.c) is a special concrete which settles itself without any vibration due to its own mass and self-weight. This will happen due to use of special admixtures which have tendency to increase the flow of concrete by reducing the viscosity nature. This particular type of concrete was developed by the japan researchers in 1988. Later it was modifies and developed in many parameter’s by UK and U.S.A researchers. This particular thesis is about the improvement of performance of the S.C.C by replacing the fines and cement of the aggregates by the waste products that obtained from the different industries. The fines are replaced partially by crushed sand obtained as quarry waste and the aluminium slag that obtained from many industries as a waste product is partially introduced as binding material By using this S.C.C the problems that are facing by the construction industries during the placement of the concrete will solve. Now days the structures are designed and made as heavy reinforced structures where the sizes of structural elements are restricted due to architectural and some structural considerations. So the concrete that poured in those elements shows the voids and honey combing it can be prevented by using this S.C.C. not only the improvement of the strength but also the construction time and cost also gets reduced by using this product, because with this material no need of vibration. It reduces the time of construction and cost regarding vibration equipment and labor. But the main problem while preparing s.c.c is to select the proper admixture to prevent the cracking and shrinkage issues. This type of concrete requires 20-25 percent higher matric paste when compared to conventional concrete. This thesis works on mainly preparing the most feasible mix for s.c.c with the partial replacement of fines and cement by above mentioned materials which makes the matrix still in plastic state without altering the original properties of the concrete. The second task is to prepare the specimens for different strength tests and like compression and tensile and bending parameters check along with the considering the shrinkage issues.

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