EFFECT OF REPLACING CRUSHED STONE IN STONE COLUMNS BY WASTE MATERIAL ON SOIL IMPROVEMENT RATIO

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Nahla Mohammed Salim ◽  
Shatha Hasan ◽  
Kawther Al-Soudany
Keyword(s):  
Bearing Capacity ◽  
Soft Clay ◽  
Soil Improvement ◽  
Waste Material ◽  
Stone Columns ◽  
Crushed Stone ◽  
Stone Column ◽  
University Of Technology ◽  
The University ◽  
Building Demolition

Many researchers’ studies have shown that stone column is the best material to use to improve the bearing capacity of clayey soils. There are millions of waste volumes resulting from daily human activities. This excess waste leads to disposal problems and also causes environmental contamination and health risks. Demolished concrete is such one waste material that is produced from building demolition in Baghdad, Iraq. This paper describes experimental work conducted at the University of Technology that was carried out to investigate the improved bearing capacity of soft clay using crushed stone, followed by replacing crushed stone with concrete waste with the same relative density and grain size. The replacement was carried using waste concrete with different percentages corresponding to 25%, 50%, 75%, and 100%. The main conclusion drawn is that the bearing capacity increased to 119% by using crushed stone column, while the bearing capacity increased to 155% by using 100% of crushed concrete waste.

scholarly journals The behaviour of the clay soil reinforced by stone column encased with geogrid under cyclic load

2018 ◽  
Vol 1 ◽  
pp. 33-38
Author(s):  
Kwa S.F. ◽  
Kolosov E.S.
Keyword(s):  
Bearing Capacity ◽  
Cyclic Load ◽  
Clay Soil ◽  
Soft Clay ◽  
Soil Improvement ◽  
Stone Columns ◽  
Excess Pore Pressure ◽  
Stone Column ◽  
Foundation Soil ◽  
Saturated Clay

The behavior of the fully saturated clay soil reinforced by stone columns subjected to cyclic load is of considerable very important in the design of railway subgrades, these soft clay soil are characterized by high settlement and low bearing capacity because of the excess pore pressure due to heavy freight trains significantly reduces the bearing capacity which causes serious problems, the used of stone column for reinforced the saturated clay soil will reduced the settlement and increase the bearing capacity. The purpose of the current research is cases study of foundation soil improvement by reduced the settlement for a building structure using stone columns system with and without geogrid encasement under cyclic load with rate of loading 5 mm/sec.

scholarly journals Stone Columns - Determination of the soil improvement factor

2011 ◽  
Vol 19 (3) ◽  
pp. 17-21 ◽  
Author(s):  
J. Pivarč
Keyword(s):  
Analytical Methods ◽  
Soil Improvement ◽  
Stone Columns ◽  
Crushed Stone ◽  
Stone Column ◽  
Liquefaction Potential ◽  
Improvement Factor ◽  
Consolidation Effect ◽  
Laboratory Models

Stone Columns - Determination of the soil improvement factorA stone column is one of the soil stabilizing methods that is used to increase strength, decrease the compressibility of soft and loose fine graded soils, accelerate a consolidation effect and reduce the liquefaction potential of soils. The columns consist of compacted gravel or crushed stone arranged by a vibrator. This paper deals with Priebe's theory (1976) on the design of an improvement factor, which belongs among the most used analytical methods and also describes the numerical and laboratory models of stone columns. The improvement factors calculated from numerical and laboratory models are compared with the improvement factors resulting from Priebe's theory.

Experimental and Statistical Study on Single and Groups of Stone Columns

2020 ◽  
Vol 857 ◽  
pp. 399-408
Author(s):  
Maki J. Mohammed Al-Waily ◽  
Mohammed Y. Fattah ◽  
Maysa Salem Al-Qaisi
Keyword(s):  
Shear Strength ◽  
Stress Concentration ◽  
Bearing Capacity ◽  
Soft Clay ◽  
Undrained Shear Strength ◽  
Stone Columns ◽  
Stone Column ◽  
Dependent Variables ◽  
Undrained Shear ◽  
Improvement Ratio

In the present study, 24 laboratory models on soft clay treated with stone columns were carried out. The results for each case are analysed for the purpose of constructing a statistical model linking the variables studied. The experiments showed that the stress concentration and bearing capacity of soil treated with stone column increase with increasing the undrained shear strength (cu), number of columns and L/d ratio. The models represent a single stone column and a group of stone columns. The studied variables are three dependent variables, the stress concentration ratio (n), bearing capacity of soil treated with stone column (q) and the settlement improvement ratio (Sr) due to the existence of stone columns. The independent variables are six: the undrained shear strength of clay soil, with three values (6, 9 and 12 kPa), the number of stone columns (1, 2, 3 and 4 columns) and the length (L) to the diameter (D) of the stone column or (L/D) ratio in two values (6 and 8). Besides, the bearing capacity of the soil treated (q) with stone columns and the settlement improvement ratio were used in some statistical models as independents. After regression analysis, a set of equations that correlate the previous variables have been suggested. The incepted values for dependent variables are close to the laboratory results.

scholarly journals DESIGN OF SUBSOIL IMPROVEMENT BELOW HALL FLOORS

2017 ◽  
Vol 10 ◽  
pp. 56
Author(s):  
Peter Turček ◽  
Monika Súlovská
Keyword(s):  
Bearing Capacity ◽  
Soft Clay ◽  
Thick Layer ◽  
Soil Improvement ◽  
Stone Columns ◽  
Clay Soils ◽  
Industrial Park ◽  
Construction Site ◽  
Geological Conditions ◽  
The Town

The construction of an industrial park is now being prepared near the town of Nitra. The investor fixed very strict conditions for the bearing capacity and, above all, the settlement of halls and their floors. The geological conditions at the construction site are difficult: there are soft clay soils with high compressibility and low bearing capacity. A detailed analysis of soil improvement was made. Stone columns were prepared to be fitted into an approximately 5 m thick layer of soft clay. The paper shows the main steps used in the design of the stone columns.

scholarly journals Improvement of Soft Soil Using Linear Distributed Floating Stone Columns under Foundation Subjected to Static and Cyclic Loading

2019 ◽  
Vol 5 (3) ◽  
pp. 702 ◽  
Author(s):  
Mahdi O Karkush ◽  
Anwar Jabbar
Keyword(s):  
Cyclic Loading ◽  
Bearing Capacity ◽  
Soft Soil ◽  
Friction Angle ◽  
Soil Improvement ◽  
Stone Columns ◽  
Stone Column ◽  
Column Material ◽  
Area Replacement Ratio ◽  
Static And Cyclic Loading

A stone column is one of the soil improvement methods that are mainly used for improving the geotechnical behavior of soft soils. For deep improvement of soft soil, the floating stone columns are considered the best and effective economically which provide lateral confinement and drainage and longitudinal skin friction. In this study, six tests were carried out on the natural soft soil of undrained shear strength of 5.5 kPa improved by single and two linear distributed floating stone columns. The stone column dimensions are 30 mm in diameter and 180 mm in length and the stone column material is sand of high internal friction angle of 48°. The natural and improved soil samples are tested under isolated raft foundation of dimensions 120×120 mm subjected to vertical static and cyclic loading of frequency 2Hz and continued for 50 seconds. The results showed a significant improvement in soil bearing capacity when reinforced with stone columns despite the small area replacement ratio, where the bearing capacity of improved soil increased by 120 to 145%. The compressibility of improved soil decreased by 57 to 86% in comparison with that of natural soft soil. Also, the floating stone columns reduced the porewater pressure, where the stone columns considered efficient in providing short drainage pathways. This can be one of the reasons why soil reinforced with floating stone columns hold higher cyclic and static stresses regardless the end bearing of stone columns.

scholarly journals Investigation of the Effect of Dimensional Characteristics of Stone Column on Load-Bearing Capacity and Consolidation Time

2018 ◽  
Vol 4 (6) ◽  
pp. 1437 ◽  
Author(s):  
Mohammad Reza Mohtasham ◽  
Mahdi Khodaparast
Keyword(s):  
Bearing Capacity ◽  
Clayey Soil ◽  
Stone Columns ◽  
Stone Column ◽  
Rigid Foundation ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Soil Subsidence ◽  
Behavioural Model ◽  
Consolidation Time

One of the best methods for rehabilitating loos and soft soils is the application of stone columns. This method enhances the soil properties by increasing its load-bearing capacity, decreasing the soil subsidence, and accelerating the consolidation rate. In the present paper, numerical analysis of a stone column of 10 m in length into a clayey soil using ABAQUS software is presented. The stone column was modelled based on the concept of unit cell, i.e. a single stone column with the surrounding soil. In this respect, material of the stone column was modelled using the elastoplastic behavioural model of Mohr-Coulomb, while Cam Clay behavioural model was used for the surrounding clayey soil. Furthermore, throughout the analyses performed in this study, effects of different parameters (e.g. applied load on rigid foundation, and the stone column length and diameter) on the subsidence and consolidation time of the rigid foundation were examined. The results indicated that, construction of a stone column into clayey soil decreases the subsidence and consolidation time of the soil considerably. In additions, increases in length and diameter of the stone column were found to significantly contribute to reduced subsidence and consolidation time of soil.

Influence of geosynthetic encasement on the performance of stone columns floating in soft clay

2013 ◽  
Vol 50 (7) ◽  
pp. 754-765 ◽  
Author(s):  
Sujit Kumar Dash ◽  
Mukul Chandra Bora
Keyword(s):  
Bearing Capacity ◽  
Performance Improvement ◽  
Soft Clay ◽  
Full Length ◽  
Stone Columns ◽  
Column Length ◽  
Capacity Improvement ◽  
Bulge Formation ◽  
Stiffening Effect

This paper investigates the influence of geosynthetic encasement on the performance of stone columns floating in soft clay. It was found that with unencased columns the bearing capacity improvement is about 3.5 fold, but with geogrid encasement the improvement increases to 5 fold, where 60% of the column length is encased. With full-length encasement (i.e., 100%), the improvement is only about 3 fold. It is therefore evident that partially encased floating columns are superior to the fully encased ones. In contrast, with end-bearing stone columns, full-length encasement is reported to have exhibited better performance improvement than the partially encased ones. In the former case (floating columns), it is the bulge formation at a deeper depth that enhances the bearing capacity, while in the latter case (end-bearing columns), it is the stiffening effect of the encasement that enables the column to transmit the surcharge pressure onto the competent strata below.

scholarly journals ANALISIS CARA PENINGKATAN DAYA DUKUNG FONDASI DANGKAL PADA KONSTRUKSI GEDUNG BERTINGKAT

2020 ◽  
Vol 3 (3) ◽  
pp. 897
Author(s):  
Feric Antonius ◽  
Alfred Jonathan Susilo
Keyword(s):  
Bearing Capacity ◽  
Friction Angle ◽  
Shallow Foundation ◽  
Soil Reinforcement ◽  
Crushed Stone ◽  
Unit Weight ◽  
Stone Column ◽  
Deep Foundation ◽  
High Rise ◽  
Crushed Limestone

ABSTRACTThe construction of high rise buildings requires a strong foundation. High rise building construction usually requires a deep foundation which requires a large cost. Therefore, shallow foundation can be used as an alternative to replace deep foundation. The main problem that arise is the low bearing capacity of the foundation which unable to carry the load. This research conducts is to find out how to increase the bearing capacity of a square footings with several reinforcement materials for high rise buildings. The analysis bearing capacity of shallow foundation is carried out manually using the Terzaghi method and the Meyerhof and Hanna method. The results of the analysis using these two methods show that soil reinforcement materials such as stone column, crushed stone, crushed limestone, construction and demolition can increase the bearing capacity of shallow foundations. The conclusions of this research with Terzaghi method obtained that the greater the value of the friction angle and unit weight of soil from the reinforcement materials, the bearing capacity of the foundation will be even greater, while the Meyerhof and Hanna method obtained that the stronger material does not always get the greatest value of bearing capacity because it depends on the type and consistency of the soil under the reinforcement layer.Keywords: bearing capacity; stone column; crushed stone; crushed limestone; construction and demolitionABSTRAKDalam perencanaan pembangunan seperti gedung bertingkat tentunya memerlukan sebuah fondasi yang kuat. Pembangunan konstruksi gedung bertingkat biasanya memerlukan fondasi dalam tetapi memerlukan biaya yang besar. Oleh karena itu, fondasi dangkal dapat digunakan sebagai alternatif untuk menggantikan fondasi dalam. Masalah utama yang timbul dari penggunaan fondasi dangkal untuk gedung bertingkat adalah daya dukung fondasi yang rendah sehingga tidak mampu memikul gaya luar. Penelitian ini dilakukan untuk mengetahui cara peningkatan daya dukung fondasi telapak persegi dengan beberapa material perkuatan tanah untuk gedung bertingkat. Analisis daya dukung fondasi dangkal dilakukan secara perhitungan manual menggunakan metode Terzaghi dan metode Meyerhof dan Hanna. Hasil analisis menggunakan kedua metode tersebut menunjukkan bahwa material perkuatan tanah yaitu stone column, crushed stone, crushed limestone dan construction and demolition yang digunakan dapat meningkatkan daya dukung fondasi dangkal. Kesimpulan dari penelitian ini antara lain menggunakan metode Terzaghi didapatkan bahwa semakin besar nilai sudut geser dalam dan berat jenis tanah dari material perkuatan yang digunakan maka nilai daya dukung fondasi akan semakin besar sedangkan metode Meyerhof dan Hanna didapatkan bahwa semakin kuat material belum tentu berpengaruh untuk mendapatkan nilai daya dukung yang paling besar karena dipengaruhi dengan jenis dan konsistensi tanah yang berada dibawah lapisan perkuatan tersebut.Kata kunci: daya dukung; stone column; crushed stone; crushed limestone; construction and demolition

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