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Foundation analysis and design
01 Jan 1968-
TL;DR: In this paper, Fondation de soutenagement et al. presented a reference record for Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08.
Abstract: Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08
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TL;DR: In this article, a series of simple and nonlinear multiple regression analyses are performed and as a result of analyses, several empirical equations are developed and it is shown that the empirical equations developed in this study are statistically acceptable.
Abstract: Nowadays, some common field tests consist of SPT test and pressuremeter test are performed in investigating the geotechnical parameters of projects such as tunneling. Due to the high cost of pressuremter test performance and its time-consuming procedure, using some empirical relations between SPT and Pressuremeter tests are recommended for primarily study of the project. The purpose of this study is to perform regression analyses between the NSPT and the uniaxial compression strength test and the pressuremeter test parameters obtained from a geotechnical investigation performed in route of 2nd line of Tabriz metro. Correlations were carried out for sandy and clayey soils separately. A series of simple and nonlinear multiple regression analyses are performed and as a result of analyses, several empirical equations are developed. It is shown that the empirical equations developed in this study are statistically acceptable.
7 citations
Cites methods from "Foundation analysis and design"
...axial stress, can be used to define elastic properties of the material (elastic (Young’s) modulus and Poisson’s ratio [7, 21, 45, 51, 53]....
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...However, it is recommended the measured N value is standardized by multiplying it by the ratio between the measured energy transferred to the rod and 60% of the theoretical free-fall energy of the hammer [7, 35]....
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Journal Article•
TL;DR: In this paper, a new technique is adopted to investigate the performance of replacement and geosynthetic reinforcement materials to improve the gypseous soil behavior through experimiental set up manufactured loaclally specially for this work.
Abstract: Existence of these soils, sometimes with high gypsum content, caused difficult problems to the buildings and strategic projects due to dissolution and leaching of gypsum by the action of water flow through soil mass. In this research, a new technique is adopted to investigate the performance of replacement and geosynthetic reinforcement materials to improve the gypseous soil behavior through experimential set up manufactured loaclally specially for this work. A series of tests were carried out using steel container (600*600*500) mm. A square footing (100*100) mm was placed at the center of the top surface of the bed soil. The results showed that the most effective thickness for the dune sand layer with geotextile at the interface, within the tested range, was found to be almost equal to the width of foundation. Therefore, under this depth, the soil was reinforced with geogrid and geotextile. It can be shown that (Collapse Settlement Reduction Factor) increases to (72%) when using two layers of geogrid and one layer of geotextile under depth of replacement equal to the width of footing. In addition, the results showed that the bearing capacity increases to (1.5-2.0) time under concentric loads and (2.5-3) under eccentric loads after replacement and reinforcement of gypseous soil. Key Word: Gypseous Soil, Dune Sand, Bearing Capacity, Reinfrocement Materials, Collapse Settlement. ةصلاخلا اشم ةدع ببس دق عقاوملا ضعب يف هيلاع بسنب برتلا هذه دوجو نا سبجلا نابوذ ببسب ةيجيتارتسلا عيراشملاو ينابملل ةدقعم لآ ةبرتلا ةلتآ للاخ ءاملا نايرج ريثأتب . ةيجيسن داومب حيلستلاو ةبرتلا ليدبت صحف تلمش ةديدج ةينقت تحرتقا ثحبلا اذه يف ضرغلا اذهل ايلحم عنص يربتخم ليدوم للاخ نم ةبرتلا فرصت نيسحتل تاكبشمو . تاصوحفلا نم ةلسلس ىرخاو ةفاج جذامنل هداعبأ يديدح قودنص يف ةرومغم ) 600 * 600 * 500 ( داعبأب لكشلا عبرم ساسأو ملم ) 100 * 100 ( جذومن طسو يف عضو ملم صحفلا قودنص يف ةشورفملا ةبرتلا . يذلا قمعلا وه ةيلمر نابثكب ةيسبجلا ةبرتلا ليدبتل رثؤم قمع لضفأ نأ جئاتنلا تنيب تسا دعب ساسلأا ضرع يواسي نأ ظحول دقو تاكبشملاو ةيجيسنلا داوملا مادخ ) Collapse Settlement Reduction Factor, CSRF ( ىلا دادزت ) 72 (% ساسلأا ضرع يواسي ليدبت قمع تحت ليتسكتويجلا نم ةقبطو درآويج نم نيتقبط مدختسن امدنع . ةبسنب دادزت لمحتلا ةيلباق نأو ) 1.5-2.0 ( و يزآرملا ليمحتلا ةلاح يف ) (2.5-3.0 يزآرملألا ليمحتلا ةلاح يف . ةيسيئرلا تاملكلا : ةيسبجلا ةبرتلا ، ةيلمرلا نابثكلا ، لمحتلا ةيلباق ، حيلستلا داوم ، رايهنلاا لوطه . Assist. Prof. Dr. Bushra Sahal. Al-busoda Bearing Capacity of Shallow Footing on Compacted Rusol Salman Filling Dune Sand Over Reinforced Gypseous Soil 533 INTRODUCTION Gypseous soil is that soil which contains enough gypsum (CaSO4.2H2O) that affect the behaviour of soil. Gypsum has specific gravity of (2.32) and its solubility of gypsum in water is (2gm/liter) at 20 C o , but the amount of dissolved gypsum can be much greater if water contains some salts (Hesse, 1971 and Khan, 2005). In Iraq gypseous soils concentrated in Mousal, Baiji, Tikrit, Sammera, North West of Baghdad, Anna, Heet, Ramadi, Falloja and they may be presented in other regions (Al-Jananbi, 2002).Gypseous soils are classified as collapsing soils. This is due to the fact that gypsum present in the soil provides an apparent cementation when the soil is dry but the intrusion of the water causes dissolution and softening leading generally to serious structural collapse (Razouki, et al, 1994). Upon wetting, most of soils show settlement. The amount of settlement varies from soil to another and is dependent on load-induced stresses. But such settlement will eventually cease after a certain period of time. However, under certain conditions and for specific types of soils, subsequent wetting may cause additional settlement. This type of settlement is termed (Collapse) (Casagrande, 1932). Many major projects suffered from several problems related to construction on or by gypseous soils, such as cracks, tilting, collapse, and leaching the soil. These problems could happen due to percolation of water into these soils causing dissolution of gypsum, which provides the cementing bonds between the soil particles. This process leads to collapse of soil structure and progressive compression, and the problem becomes more complicated if flow occurred causing continuous loss of soil mass and formation of serious cavities. For the construction of any kind of structure resting on problematic soils such as gypseous soils, there are many available methods to improve the behaviour of soil. Using Geosynthetic materials (Geotextile and Geogrid) as reinforcement, to increase bearing capacity and to decrease settlement for foundation was investigated by many researchers such as (Das, 1988, Raymond, 1992, and Soliman and Hanna, 2010). The designers have suggested partially replacing the collapsible soil with cohesionless material and using reinforcement materials and study their effects on the reduction of collapse settlement of collapsible soils when inundation was occur. EXPERMENTAL WORK 1. Classification Tests: The material used in this study was distributed gypseous soil brought from Tikrit, Salah Al-Deen Governorate and dune sand used in replacement of gypseous soil was obtained from Baiji, Salah Al-Deen Governorate. A series of tests was performed on the gypeous soil and dune sand according to ASTM procedures. Gypseous soil can be classified as (SC) and dune sand can be classified as (SP) according to the Unified Soil Classification System. The minimum unit weight of gypseous soil was determined according to the test described by (Head, 1984). It is widely accepted as standard test for sandy soils and the maximum unit weight of gypseous soil was determined according to ASTM D-64T (Bowles, 1988). Field unit weight of gypseous soil was determined by a field test (Sand Cone Method). This test was performed according to (ASTM D1556-00). The results of the maximum and minimum unit weights of gypseous soil are (14.10) kN/m and (10.75) kN/m respectively. Table (1), (2), (3), and (4) show the physical and chemical properties of gypseous soil and dune sand, respectively. 2. Test Box: The soil beds were prepared in a steel box with inside dimensions (600*600) mm and (500) mm in height. The sides and bottom were made of (5) mm thickness plate;the purpose of the thickness is to give rigidity against pressure which may generate during loading of the soil. One face of the steel box is made from Plexiglass with dimensions (300*300) mm. The box placed over (800) mm width and (1000) mm length of strong steel base, which is connected to a stiff loading frame. The frame consists of two columns of steel channels, which is in turn bolted to a loading platform. This platform allowed to slide along the columns and can be fixed at any desired height by means of slotting spindles and holes provided at different intervals along the columns. The footing was made of steel plate of a thickness of (3) mm. . The footing was connected to suitable steel wings to facilitate the measurement of settlement. Ahydraulic jack was used to apply an axial loading on footing. The load on the footing was measured using proving ring of (20) kN capacity, while the settlement was measured by two dial gauges (0.01) mm fixed on the footing by two magnetic holders. Ageneral view of the Journal of Engineering Volume 19 may 2013 Number 5 534 manufactured testing equipment is shown in Figure (1). A sketch for the test box showing some of the studied parameters is shown in Figure (2). The detailed description of the model is explained in the following paragraphs. The reinforcement used is polymer geomesh (Geogrid and Geotextile). Table (5) shows the properties of geogrid, and Table (6) shows the properties of geotextile, as supplied by Building Research Center (Iraq). Figure (3) shows the geogrid and geotextile used in this work. TEST PROCEDURE FOR MODEL LOADING 1. Collapse Test Procedure: 1.Using raining technique, gypseous soil is placed in the steel box at field density (12.9) kN/m and in situ moisture content (3.2%). The surface was leveled and checked by a bubble ruler (Balance). 2.When reaching the desired depth of soil in the steel box, sqaure footing was placed at the center of the test box. 3.For the tests on replaced gypseous soils, geotextile sheet was placed above the gypseous soil. Dune sand was placed in the steel box above the geotextile by raining technique to reach a relative density of (75%) and a unit weight of (16) kN/m. 4.For testing using geogrid within the dune sand layer, the geogrid was placed at different depths. 5.The base of the proving ring is made just in touch with the footing. The zero (initial) reading was recorded. Two magnetic holders with dial gauges were connected to the edges of the box. 6.Load increments are applied until settlement readings are less than (0.01) mm. 7. When reaching the inundation stress then another increment is applied, water is added to soil in the steel box, while the applied load was kept constant. The soil becomes fully saturated. Loads and settlements are recorded for the following (24) hours. 2. Bearing Capacity Test Procedure: The test was conducted by using non repetitive static plate load test method according to the procedures of ASTM D1194-94. The bearing capacity was determined for various thicknesses of gypseous soil beds. In each test, the gypseous soil was placed in layers (5) cm thick. The placement density was controlled using raining technique.The gypseous soil was carefully spreaded in two perpendicular directions to ensure uniform density. When the final layer was layed, the surface was carefully leveled with the aid of straight edge. Then, the foundation was fixed in the center of test box in x and y direction in concentric loading and at determined eccentricity in case of eccentric loading and then the two magnetic holders with dial gauges in the edge of the box was connected. The load was continuously applied through the hydraulic jack. The applied load was recorded from the proving ring read
7 citations
Cites methods from "Foundation analysis and design"
...Bowles, J. E., (1988) ''Foundation Analysis and Design'', Fourth Edition, McGraw-hill, New York....
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...It is widely accepted as standard test for sandy soils and the maximum unit weight of gypseous soil was determined according to ASTM D-64T (Bowles, 1988). Field unit weight of gypseous soil was determined by a field test (Sand Cone Method). This test was performed according to (ASTM D1556-00). The results of the maximum and minimum unit weights of gypseous soil are (14.10) kN/m(3) and (10.75) kN/m(3) respectively. Table (1), (2), (3), and (4) show the physical and chemical properties of gypseous soil and dune sand, respectively. 2. Test Box: The soil beds were prepared in a steel box with inside dimensions (600*600) mm and (500) mm in height. The sides and bottom were made of (5) mm thickness plate;the purpose of the thickness is to give rigidity against pressure which may generate during loading of the soil. One face of the steel box is made from Plexiglass with dimensions (300*300) mm. The box placed over (800) mm width and (1000) mm length of strong steel base, which is connected to a stiff loading frame....
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...It is widely accepted as standard test for sandy soils and the maximum unit weight of gypseous soil was determined according to ASTM D-64T (Bowles, 1988)....
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TL;DR: Pottger et al. as discussed by the authors obtained BEng and Honours degrees in Civil Engineering from the University of Pretoria and also obtained a Master's degree in Geotechnical Engineering, researching the differences between complex and simple methods of analysis.
Abstract: JEAN-TIMOTHY POTGIETER earned BEng and Honours degrees in Civil Engineering from the University of Pretoria. He also obtained a Master’s degree in Geotechnical Engineering, researching the differences between complex and simple methods of analysis. Jean has five years’ work experience in civil engineering, specialising in geotechnical-related projects – he has worked in the fields of tailings dams, foundation design and site investigations in South Africa and on the African continent. He is currently studying towards an MBA degree at the University of Cape Town. He is also currently the vice-chair of the ISSMGE young person’s presidential group.
7 citations
Cites methods from "Foundation analysis and design"
...The stiffness parameters (E’ and v’) were estimated for a dense material based on Bowles (1996). analYses conducted soil-nail supported excavation An 8.5 m deep soil-nailed excavation was analysed as shown in Figure 3....
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TL;DR: In this paper, an explicit finite difference code FLAC was used to simulate the rise of ground water table in granular soil and the resulting additional settlement was studied, and the linear elastic model gave two times settlement in saturated soil, agreeing with Terzaghi's (1943) statement.
Abstract: Shallow foundations are designed such that their expected settlements are limited to 25 mm, and the safety factor against possible bearing capacity failure is 3. When the water table is close to the footing, appropriate design parameters are used to reflect the less stiff soil beneath the water table. When future rise in water table is expected, substantial additional settlement might occur. Terzaghi (1943) suggested that the Young’s modulus of saturated granular soil is ∼50% of that of the dry soil, which leads to doubling the settlement in saturated soil when the water table rises to the foundation level. In this paper, an explicit finite difference code FLAC was used to simulate the rise of ground water table in granular soil and the resulting additional settlement was studied. Using linear elastic model gives two times settlement in saturated soil, agreeing with Terzaghi’s (1943) statement. Using hyperbolic nonlinearly elastic soil model shows that the correction factor varies with the stress level as...
7 citations
Cites background from "Foundation analysis and design"
...…correction factor can be defined as Cw~ settlement with water table below the footing level settlement in dry sand (1) There are several suggestions for Cw as reported in the literature (Alpan, 1964; Bazaraa, 1967; Bowles, 1977; NAVFAC, 1982; Peck et al., 1974; Teng, 1962; Terzaghi and Peck, 1967)....
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...There are several suggestions for Cw as reported in the literature (Alpan, 1964; Bazaraa, 1967; Bowles, 1977; NAVFAC, 1982; Peck et al., 1974; Teng, 1962; Terzaghi and Peck, 1967)....
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...0B (Teng, 1962; Peck et al., 1974; Bowles, 1977) to 2?...
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...The depth at which the water table rise starts influencing the settlement varies from 1?0B (Teng, 1962; Peck et al., 1974; Bowles, 1977) to 2?0B (Terzaghi and Peck, 1967; Alpan, 1964)....
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31 Jul 2017
7 citations
Cites methods from "Foundation analysis and design"
...117 was used to find the subgrade modulus ks (Bowles 1996; Selvadurai 2013; Vesic 1961)....
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