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.

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 Impact of Using Different Types of Soft Soils Treated by Stone Columns on Creep Behavior

2022 ◽  
Vol 961 (1) ◽  
pp. 012052
Author(s):  
Sura Tawfeeq Al-Auqbi ◽  
Nahla M. Salim ◽  
Mahmood R. Mahmood
Keyword(s):  
Soft Soil ◽  
Horizontal Displacement ◽  
Cohesive Soil ◽  
Stone Columns ◽  
Stone Column ◽  
Geometric Conditions ◽  
Improvement Factor ◽  
Soil Deposits ◽  
Different Types ◽  
The Impact

Abstract The stone column technique is an effective method to increase the strength of soft cohesive soil, which results in a reduction in foundation settlement and an increase in bearing capacity. The topic of restraining creep settlement through the use of stone columns techniques has gained increasing attention and consideration; because stone columns are widely used to treat soft soil deposits, caution should be applied in estimating creep settlement. We discovered a reversible relation between shear parameters and the creep settlement in floating stone columns; while, in case of end-bearing stone columns shows a direct positive relation between shear parameters and the creep settlement, and the creep settlement began at the primary settlement. The shear parameters affected the improvement factor (n) of creep settlement in both floating and end-bearing stone columns. The standard creep coefficient’s n values in floating and end-bearing conditions were more significant than the low creep coefficient’s n values in forwarded geometric conditions. The stress in both floating and end-bearing stone columns was increasing and uniformly distributed along the length of the floating stone column and in the case of end-bearing stone column was limited to the stiffness layer; the maximum vertical stress was in the central point of the embankment. The embankment’s maximum horizontal displacement occurred on the edge.

scholarly journals Analisis Potensi Likuefaksi dan Perbaikan Tanah dengan Stone Column: Studi Kasus pada Coal Shelter PLTU Lontar, Banten

2021 ◽  
Vol 17 (1) ◽  
pp. 27-35
Author(s):  
Yuli Fajarwati ◽  
Rama Indera Kusuma
Keyword(s):  
Safety Factor ◽  
Soil Improvement ◽  
Silty Sand ◽  
Stone Columns ◽  
Stone Column ◽  
Silty Clay ◽  
High Demand ◽  
Research Site ◽  
New Generation ◽  
Liquefaction Analysis

ABSTRACT The high demand for electricity needs requires the availability of new generation sites. The new plant developed is a PLTU in Lontar. The condition of coal shelter as a research site dominated by silty clay and silty sand and located in the earthquake zoning is high that the planning of the coal shelter area must accordance with the feasibility of building establishment, it is necessary to analyze the potential liquefaction and improvement methods. Soil improvement efforts to reduce the potential for liquefaction include soil improvement with stone columns. The method of liquefaction analysis in this study uses the method developed by Idriss and Boulanger. The results of the analysis of the potential for liquefaction at BH-1 occurred at a depth of 3-16 m and at BH-3 the potential for liquefaction occurred at a depth of 4-24 m. Potential of the thickest layer for liquefaction is at BH-3 with a depth of 24 m. Improvement with a stone column can reduce the potential for liquefaction and can increase the value of the safety factor against the potential for liquefaction at the coal shelter location. Improvement analysis with a stone column using Plaxis software, the value of the safe factor after installing the stone column at BH-1 FS 2.89, at BH-3 FS became 2.65. ABSTRAKBanyaknya permintaan kebutuhan listrik yang tinggi diperlukan ketersediaan lokasi pembangkit baru. Pembangkit baru yang dikembangkan yaitu PLTU Batubara di Lontar. Kondisi coal shelter sebagai lokasi penelitian yang didominasi oleh lapisan tanah lempung kelanauan dan pasir kelanauan serta berada pada zonasi gempa cukup tinggi sehingga perencanaan area coal shelter harus memenuhi syarat kelayakan pendirian bangunan, maka perlu dilakukan analisis potensi likuefaksi serta metode perbaikannya. Upaya perbaikan tanah untuk mengurangi potensi likuefaksi yaitu perbaikan tanah dengan stone column (kolom batu). Metode analisis likuefaksi pada penelitian ini menggunakan metode yang dikembangkan oleh Idriss dan Boulanger. Hasil analisis potensi likuefaksi pada titik BH-1 terjadi di kedalaman 3-16 m dan pada titik BH-3 potensi likuefaksi terjadi pada kedalaman 4-24 m. Lapisan yang paling tebal mengalami potensi likuefaksi ada pada titik BH-3 dengan kedalaman 24 m. Perbaikan dengan stone column dapat mengurangi potensi likuefaksi dan mampu meningkatkan nilai faktor keamanan terhadap potensi likuefaksi di lokasi coal shelter. Analisis perbaikian dengan stone column menggunakan software Plaxis, nilai faktor aman setelah dipasang stone column pada titik BH-1 FS 2,89, pada titik BH-3 FS menjadi 2,65.

scholarly journals Settlement of Geosynthetic Encased Stone Columns Liquefaction Condition in Box Culvert

2021 ◽  
Vol 21 (1) ◽  
pp. 40-51
Author(s):  
Maftuh Ahnan ◽  
◽  
Putera Agung Maha Agung ◽  
Keyword(s):  
Bearing Capacity ◽  
Soil Layer ◽  
Soil Improvement ◽  
Stone Columns ◽  
Liquefaction Potential ◽  
The Stability ◽  
Unsafe Condition ◽  
Box Culvert ◽  
Settlement Analysis ◽  
Spt Data

When the box culvert system is placed on a sandy soil layer with a relatively low bearing capacity and is disposed to potential liquefaction, the soil layer must be repaired to avoid damages to the box culvert structure. The proposed method is Geosynthetic Encased Stone Columns (GESC) to increase the bearing capacity and anticipated the liquefaction potential. however, to meet the criteria for a stable and safe GESC soil improvement in liquefaction conditions, the value of the settlement must meet the requirements for the settlement permit limit. This research was conducted to determine the potential for liquefaction at the study location, to calculate the value of single and group settlements in liquefaction conditions and to analyze the stability of single and group settlements including safe or unsafe in liquefaction conditions. Analysis of liquefaction potential was analyzed based on SPT data using the Valera and Donovan method, and settlement analysis applied the Almeida and Alexiew method. The analysis shows that potential liquefaction due to an earthquake with a magnitude of 9.0 SR will be at a depth of 4 to 8 m. Single and group settlements (144 sets) with an installation distance of 1.2 m with a diameter of 0.4 m and at a depth of 10 m are 246.23 and 214.92 mm, respectively. The entire GESC system is considered to be in an unstable and unsafe condition against potential liquefaction and box culvert loading.

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 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.

Analytical Methods for Determination of Balofloxacin in Tablets

2012 ◽  
Vol 2 (8) ◽  
pp. 66-68
Author(s):  
Shreya Nayak ◽  
◽  
Sanjay Pai P.N. Sanjay Pai P.N.
Keyword(s):  
Analytical Methods

The relationship between musty-odor-causing organisms and water quality in Lake Biwa

1995 ◽  
Vol 31 (11) ◽  
pp. 153-158 ◽  
Author(s):  
M. Kajino ◽  
K. Sakamoto
Keyword(s):  
Water Quality ◽  
Data Analysis ◽  
Green Algae ◽  
Analytical Methods ◽  
Lake Biwa ◽  
Blue Green Algae ◽  
Odor Compounds ◽  
Musty Odor ◽  
The Relationship

Musty odor has occurred annually in Lake Biwa since 1969. Osaka municipal waterworks, which is located downstream of Lake Biwa, has made many efforts to treat musty-odor compounds produced in Lake Biwa from spring through autumn. With the development of analytical methods for the determination of musty-odor compounds, we have been able to confirm that planktonic blue-green algae are the major causes of the musty-odor occurrences. The relationship between the growth of blue-green algae and the water quality was not so apparent. However, through our data analysis focusing on the relationship between musty-odor occurrences due to Phormidium tenue or Oscillatoria tenuis and some nutrients in Lake Biwa, we found that the concentration of nitrate in water may be an important parameter for the estimation of growth of the algae and the musty-odor behavior.

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