scholarly journals Probabilistic Analysis of Shallow Foundation Settlement considering Soil Parameters Uncertainty Effects

2017 ◽  
Vol 07 (05) ◽  
pp. 731-743 ◽  
Author(s):  
Mahmoud Nazarzadeh ◽  
Soheil Sarbishe-ee
2017 ◽  
Vol 8 (3) ◽  
pp. 143
Author(s):  
Rifki Asrul Sani

ABSTRAKSeiring dengan terjadinya longsoran di beberapa titik wilayah di bukit Hambalang, maka diperlukan kajian data kondisi geologi teknik berupa sifat fisik dan mekanik tanah serta batuan bawah permukaan, terutama mengenai daya dukung tanah dalam menahan beban bangunan di atasnya agar tidak terjadi penurunan. Metode yang digunakan dalam penelitian ini dibagi menjadi tiga, yaitu metode penelitian studio dengan memanfaatkan data-data sekunder yang telah ada, metode penelitian di lapangan melalui pemetaan geologi untuk mendapatkan data litologi yang tersingkap di permukaan, zonasi longsoran yang terjadi, dan identifikasi kekuatan tanah hasil pemboran geoteknik dengan Standard Penetration Test (SPT), serta metode penelitian di laboratorium untuk mendapatkan parameter sifat fisik dan mekanik tanah sebagai penunjang data daya dukung tanah serta geologi teknik daerah penelitian. Hasil perhitungan fondasi dangkal untuk general soil shear condition dan local soil shear condition dapat disimpulkan bahwa daya dukung tanah yang diizinkan (qa) untuk setiap kedalaman yang paling tinggi pada fondasi bujur sangkar (square footing) dan nilai tertinggi yang terdapat pada kedalaman 2 m, yaitu 57,32 ton/m2 dan 36,11 ton/m2. Fondasi yang paling rendah untuk semua kedalaman pada fondasi menerus (continuous footing) untuk kedalaman 2 m memiliki nilai 34,49 ton/m2 dan 21,25 ton/m2. Berdasarkan data SPT, nilai daya dukung yang diizinkan (qa) pada masing-masing titik bor berkisar pada rentang 2,85 ton/m2 sampai 16,85 ton/m2. Kata kunci: longsoran, daya dukung, Standard Penetration Test (SPT). ABSTRACTAlong with the landslide in some areas on the Hambalang Hill, it needs data of engineering geological study such as mechanical and physical properties of soil also subsurface rocks. Especially regarding the soil bearing capacity in order to restrain the building from settlement. There are three methods which used in this research, those are studio research by using secondary data, fieldwork research that is geological mapping conducted to obtain data on lithological rocks at surface, landslide zone and soil strength identification from geotechnical drilling with Standard Penetration Test (SPT) and laboratory research to obtain the soil parameters of physical and mechanical properties, which used to support soil bearing capacity data and engineering geology in research area. The calculation results of the shallow foundation for general soil shear condition and the local soil shear condition it could be concluded that the allowable bearing capacity for all depth which is highest at the square footing and the highest value found to a depth of 2 m, that is 57.32 ton/m2 and 36.11 ton/m2. The lowest foundation for all the depth of the continuous footing to a depth of 2 m had value 34.49 ton/m2 and 21.25 ton/m2. Based on data from SPT, the allowable bearing capacity on each of borehole ranging from 2.85 ton/m2 to 16.85 ton/m2. Keywords: landslide, bearing capacity, Standard Penetration Test (SPT).


Author(s):  
Khawaja Adeel Tariq ◽  
Muhammad Moeen Soharwardy ◽  
Nadeem Ahmed Tabessum

This study deals with the evaluation of soil engineering characteristic along the proposed route of Jalalpur irrigation project. The proposed JIP (Jalalpur Irrigation Project) is located along the right bank of Jhelum River in Tehsil PDK (Pind Dadan Khan) and Tehsil Khushab of District Khushab. JIP is funded by ADB (Asian Development Bank). The JIP will enhance crop production in Tehsil PDKand Khushab. Farmers will be benefited through JIP as they will get regular supply of water through canal. It will also create job opportunities for local people and will lead to the prosperity of the Project area. Detailed soil investigation along proposed route was carried out by M/S GEO BAND. Straight rotary method of drilling was used. The recovered soil samples and water samples were tested in laboratories. The detailed engineering analysis was performed and soil parameters along with bearing capacities are suggested. Results have indicated variations in SPT values along the proposed route. The top layer of soil along proposed route is mostly Silty Clay with variation along the depth. The proposed bearing capacity for shallow foundation is 1.25 ton/ft2 (120 kN/m2) at depth of 5ft (1.5 m) beneath footing, and for bored piles having diameter of 2.5 ft (0.76 m) at a depth of 50 ft (15 m) is recommended as 70 ton (685 kN). The results presented in this study will be helpful in deciding the detailed foundation design of the engineering structures along the proposed route of JIP.


2020 ◽  
Vol 57 (4) ◽  
pp. 595-607 ◽  
Author(s):  
Yongxin Wu ◽  
Yufeng Gao ◽  
Limin Zhang ◽  
Jun Yang

The effects of the first four statistical moments defining the statistical characteristic of elastic modulus on the probabilistic foundation settlement are investigated in this study. By combining the Hermite probability model and spectral representation method, a method to simulate nonGaussian homogenous fields based on the first four statistical moments is proposed. Linear elastic finite element models are employed to study the total settlement and the differential settlement of a shallow foundation. Probabilistic measurements of total–differential settlement obtained by the Monte Carlo simulations are presented. For the cases considered, the effects of skewness and kurtosis defining the probabilistic characteristic of elastic modulus on the total–differential settlement of a probabilistic foundation are illustrated. The computed results show that the value of skewness has a more significant effect on the probabilistic foundation settlement than kurtosis, and the case with the smallest skewness is observed as the most critical one.


2012 ◽  
Vol 446-449 ◽  
pp. 1935-1939 ◽  
Author(s):  
Hong Sheng Qiu ◽  
Shu Shi ◽  
Mei Li

The large-size flexible shallow foundation (LFSF) can not be designed fully in accordance with the shallow foundation design specification, for there are differences between LFSF and traditional shallow foundation. Taking the foundation project of Shenzhen Mawan port for example, considering the interaction between foundation and ground base and adopting a non-linear foundation model, the impact of foundation parameters and load conditions on basal pressure and foundation settlement were simulated to value adoption of the height-width ratio by finite element method. Analysis showed that soil physical parameters of elastic modulus, Poisson's ratio had great impacts on basal pressure and foundation settlement, and the accuracy of these parameters should be ensure in modeling. However the effects of expansion angle and cohesion were relatively small. The values of expansion angle and cohesion can refer to design specification. Foundation of this type mainly focus on flexural design.


Author(s):  
Andrew Deeks ◽  
Hongjie Zhou ◽  
Henry Krisdani ◽  
Fraser Bransby ◽  
Phil Watson

This paper describes a new framework for the geotechnical design of pipeline-related foundations (e.g. foundations for PLETs and Tees) designed to slide directly over the seabed during pipeline operation. This approach can present considerable savings in terms of fabrication and construction costs because of reduced foundation sizes. Over the design life, a pipeline is likely to endure many thermal/ pressure load cycles due to product and flow rate variations during operation. These cycles result in the foundation sliding back and forth across the seabed within a footprint. These loads and corresponding motions impose cyclic shear stresses on the soil that can (i) degrade foundation bearing capacity and (ii) cause additional foundation settlement. Often the key design consideration is whether or not the cumulative settlements will eventually compromise the integrity of the pipeline system to which the PLET and its associated foundation are attached. In addition to consolidation and creep, two key mechanisms are shown to control cyclic foundation settlement: (i) bearing mechanism induced burial and (ii) cyclic shear stress driven soil volume reduction. Their relative significance depends on the soil conditions (soil state) and input pipeline movements. The paper presents key aspects required for the design of direct on-seabed sliding foundations, including the soil parameters and associated testing required. Validation of the design approach is illustrated by comparison to laboratory model tests performed on carbonate soils. The impact of soil properties on potential foundation performance is illustrated with a design example and the importance of conducting site specific soil testing and settlement analyses is emphasised. It is also illustrated that close integration of the pipeline, structural and geotechnical analysis is necessary to reliably quantify system performance of these novel foundations.


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