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This paper investigates the behavior of two parallel foundations resting on the cohesionless soil for different foundations. As there are many empirical and analytical studies of shallow contiguous foundations on the sand in various conditions, dimensions, and forms; where The attempts to investigate the behavior of soils under stress from two close foundations can be traced back to [1], six decades ago but there are very few studies on the effect of deep foundations on adjacent shallow foundations, and this is what the researcher will address. The impact of interference on tilt, settlement, differential settlement, total normal stress, and pressure are studied using the finite element PLAXIS 3D-2021[2]. The sand is stimulated using the Mohr-Coulomb soil model[3]. A parametric study is performed for different clear spacing between the foundations' S' is varied from 0B to 5B until effects end in numerical studies. It also presents the impact of the Variation length of piles on the interface. Observe the reduction of the effects of neighboring high buildings due to using piles, where the differential settlement and tilt were reduced by about 32.5% and 47.5% when using piles of lengths 9 m and 15 m, respectively, with comparing with the raft foundation in the distance 0B between the two foundations with a load of 12.5 KN/m² for old building and load of 200 KN/m² for a new building. [ABSTRACT FROM AUTHOR]

This research focuses on investigating the bearing capacity and settlement of dry sandy soil by the use of physical modelling tests involving the loading of the surface of the foundation on the dry sand with various relative densities (Dr=50, 75, 95). The results indicated that increasing the relative density multiplies the obtained bearing capacities. In general, the load-settlement curves showed non-linear behaviour for the sand, indicating that the settlement of the footing increased with increasing the applied loading until failure occurred. Increasing the relative density from 50% to 75% and from 75% to 95% increased the bearing capacity by about 50% in each case. For the failure mechanism of both footings with dense and very dense sand, general shear failure with total rupture of the soil was observed, and a local shear failure was observed for the sand with medium relative density. [ABSTRACT FROM AUTHOR]

The phrase "skirted foundation" refers to shallow foundations having vertical or sloping thin structural components known as "skirts" that restrict the soil beneath their foundation, to increase the load carrying capacity of the soil or to give scour protection that penetrates the soil. A structure is made with the skirt to confine the soil's mass and operate as a soil block to migrate loads of the super-structure to depths at which the soil is stronger. Different shapes of existing circular, rectangular, and square foundations can be used for skirts. The skirt on a foundations' perimeter has long been used to enhance the effective depth of foundations. This study examined and conducted the soil bearing of skirted foundations on sandy soils with varying relative densities cases (loose, medium, and dense) with different D/B (Depth/Width) ratios. A physical model was created to simulate the strip foundation and compare these cases. The results show that when the sand's relative density increases, the load carrying capacity increases, and that dense sand has a higher value than medium and loose sand. But the percentage of improvement of loose sand is higher than that of medium and dense sand, this leads to the use of Skirted foundations in loose sand as an alternative solution to the use of deep foundations or costly soil improvement methods. [ABSTRACT FROM AUTHOR]

Small scale model was employed to investigate the load carrying capacity of square footing on sand soil reinforced by geotextile materials. The effects of central and eccentrically load values on shallow foundation and depth of the single layer of geotextile sheet and the spacing ratio of two sheets of geotextile on load capacity and vertical settlement were investigated. The results of the experimental study show that the optimum depth ratio of a single layer of geotextile sheet is (U/Df=0.6) which gives the maximum bearing capacity. When the value of (U/Df) becomes equal to or greater than (1.5) has no impact on the relative improvement of sand soil at various loading cases while the best vertical spacing for using a double layer under footing is found (Z/Df =0.6) for varies loading cases. The rate bearing improvement increases up to (100% and 90 %), for central and eccentrically loading conditions, respectively when using a single geotextile sheet under foundation at optimum depth ratio while the increases in the rate of bearing improvement are found at about (74% and 50%) for central and eccentrically loading conditions, respectively when using double reinforced layer under footing at optimum vertical spacing. [ABSTRACT FROM AUTHOR]

Several techniques have been developed to predict the stability of shallow foundations over the years. However, methods for predicting the necessary degree of detail and consistency have not yet been developed. This study applied the method to a deep neural network (DNN). The expected shallow settlement parameters are carefully selected. It was concluded that a deep neural network (DNN) appears to be a viable solution as it has been used successfully in many diagnostic applications in geotechnical engineering. In this paper, the precipitation values of gypsum soils were predicted under the influence of applied load using the deep learning technique. The study found that this model is very good in predicting soil precipitation and found convergence between real and expected values. The deep neural network model showed a more significant performance with mean absolute and mean squared errors, which were 0.0290 and 0.0387. The DNN model recorded the efficiency and variance computation coefficient at a good rate. It is concluded that a deep neural network model can be used to predict the stability of a shallow foundation on gypseous soil. [ABSTRACT FROM AUTHOR]

To investigate the effect of the different parameters on the behavior of shallow foundations when they are subjected to pullout loads in cohesionless soil, the current study was executed this aim. The soil was brought from Al-Najaf city; the physical properties were obtained by conducting laboratory tests in the laboratories of the University of Kufa/civil engineering department. The parameters which were studied in this investigation were soil state (loose, dense), foundation shape, and embedded depth (Df). forty tests were performed for two soil states and five different foundation shapes (square, circular, and rectangular with different (L/B) ratios from (2 to 4)) at a different depth from (10 to 40) cm for (D/B) ratio from (1 to 4). The experiment results are represented by a drawing of pullout load at failure vs vertical displacement for each test. The experimental test results show the effects of these parameters on the pullout capacity of shallow foundations in cohesionless soil. It is clear that the soil density has significant effects on the behavior of shallow foundations, the pullout capacity increased when the relative density (Rd%) changed from (20% to 72%), The pullout capacity increased with increasing foundation dimensions (L*B) and decreased for circular ones under the same conditions by considering the square shape as reference for comparison. The pullout capacity increase with increasing foundation depth (Df) for all foundation types at two soil state. the foundation depth (Df) greatly influences the pullout capacity more than the other parameters. [ABSTRACT FROM AUTHOR]

The major concern for an efficient design of structures is to provide accurate predictions of the ultimate bearing capacity of soil underneath their footings. Direct measurement of the ultimate bearing capacity in the field necessitates high costly and time-consuming. Therefore, during the last decades other methods were adopted, such as theoretical methods that depend on the mechanical properties of the soil and empirical methods that depend on the results of field tests. The major drawback of theoretical methods is that they are built on some simplified assumptions. Thus, they may do not yield accurate estimates. This study is considered as an attempt to assess the effectiveness of some of these methods and obtained the most accurate one. This goal accomplished by evaluating and ranking of five commonly used methods which were Terzaghi (1943), Meyerhof (1965), Hansen (1970), Vesic' (1975), and Michalowski (2005). The rank analysis was conducted for aforementioned methods based on a total of 193 case histories from published literature. According to the obtained results, Vesic's method was ranked first with a rank index of 5, while Meyerhof's and Michalowski's methods were ranked last with a rank index of 18. Hence, it can be concluded that the bearing capacity equation proposed by Vesic' in 1975 can be utilized with high confidence for predicting the ultimate bearing capacity of the shallow foundation based on mechanical soil properties. [ABSTRACT FROM AUTHOR]

An extensive laboratory test program was planned to satisfy the targets of this research which consists of studying the effect of depth of the first layer, number of reinforced layers, varies types of soils, and different shapes of foundations on performance of shallow foundations on geogrid soil reinforcement. This research included manufacturing a new test machine for measuring the bearing capacity (BC) of different types of foundations rested on different types of reinforcement soils. Three types of foundation was used: strip, rectangular and square foundation. The type of geogrid material was the biaxial geogrid. The research considered three types of soils: clayey soil, sandy and sandy underlain by silty clay soil. The results obtained through this study revealed an increase in the bearing capacity for specific values of design parameter. It is concluded that the depth of the first layer affects the results. When the depth of the first layer increases, the bearing capacity of foundation decreases. Optimum value of the ratio of first layer depth to the width of foundation (u/B) was about 0.33 for clayey soil and 0.25 for sandy soil. The influence depth of reinforcement layer (d/B) was 1.25 at silty clay and sandy soil. Optimum number of reinforcement layers about 3 for silty clay and sandy soil. For sandy soil, the bearing capacity ratio (BCR) increased with increasing the number of reinforcement layers in different proportions. For the shape of footing, the square footing showed a maximum value of bearing capacity of foundation on silty clay and sandy soil compared to other types of foundations. [ABSTRACT FROM AUTHOR]

Landscapes and real estates are becoming very expensive day after day incorporated with the explosive increase in populations. Leaving a property estate due to poor soil engineering properties is not an option today. This will open tremendous doors to find solutions to increase the bearing capacity, reducing settlement by increasing soil strength properties. The trend of solutions can go in two directions, one direction as to stabilize in-situ soil, while the other goes into changing foundation configuration such as to use deep instead of shallow foundation and using the screw piles will settle into the second option. Using the helix piles is rather considered a fresher technique compared to the conventional piles. The mechanism of the screw piles is complicated same as the ordinary piles, but with the same objectives. This research is concerned to show the improvement obtained in using the helix and bulb pile techniques in improving the carrying capacity of conventional piles in soft clay. As such a laboratory model is utilized having dimensions of 30cm diameter and 55cm height. Three types of piles (screw, conventional and bulb) are used in this study. Test results reveal that by far the helix-type pile is more superior in providing higher bearing load capacity and stiffness compared to the bulb piles and the conventional ones. Double-helix increased the load capacity compared to conventional pile by about six times, for single about 3.5 times measured at limiting values. For stiffness 10 times and 6 times are recorded. Double bulb increased loading capacity by 3.5 times and 2 times for single bulb. About stiffness, the increase is 2.5 and one time respectively. [ABSTRACT FROM AUTHOR]

The bearing capacity, footing depth, and the settlement behavior are representing the major factors that governing the design of shallow foundation. This research is focused on the behavior of the bearing capacity and the subsequent settlement for the square, circular, and rectangular footing foundation. Three modes of (D/B) ratio are used in this study (0, 1/3, and 2/3) under earthquake loading which are simulating by using finite element 3D PLAXIS numerical package. A Linear Elastic soil model (LE) is utilized to simulate the footing materials in soil. A Hardening soil model (HSM) is used for soil materials. The results of the analysis show a second order relation between the 2D bearing capacity coefficients and the earthquake horizontal acceleration; the shape of footing has effect on the magnitude of dynamic bearing capacity. The footing depth underground surface also effect on the footing behaviour, there is a relationship between the footing depth and settlement when the footing is subjected to earthquake loading, and the relationship between the footing depth and settlement is linear. [ABSTRACT FROM AUTHOR]

As a result of the design requirements, in many situations, shallow foundations are constructed close together, which leads to a change in the behavior of thes oil supporting the foundations due to the development produced by the interference of foundations in the failure envelope of both foundations, which changes the properties of the soil in bearing capacity and settlement. This study presents a systematic review the available analytical studies that studied the problem of interference of shallow foundations on different types of soil. This review has shown an increase in the soil bearing capacity and settlement with decrease of distance between adjacent foundations rested on different types of soil. Some of these studies showed the occurrence of the tiltas a result of the interference of the foundations based on clay soil. [ABSTRACT FROM AUTHOR]