| تعداد نشریات | 286 |
| تعداد نشریات سازمان | 84 |
| تعداد شماره‌ها | 2,944 |
| تعداد مقالات | 33,229 |
| تعداد مشاهده مقاله | 43,865,924 |
| تعداد دریافت فایل اصل مقاله | 20,372,038 |
تحلیل احتمالاتی دو متغیره تغییرات زمانی فشار آب منفذی در حین فرآیند تحکیم پی سازه | ||
| تحقیقات مهندسی سازه های آبیاری و زهکشی | ||
| دوره 24، شماره 90، خرداد 1402، صفحه 91-113 اصل مقاله (2.17 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22092/idser.2023.363197.1551 | ||
| نویسندگان | ||
| امیر ملک پور* 1؛ نیما صادقیان2؛ محمدجواد فرخی3 | ||
| 1استادیار گروه مهندسی آب، دانشکده علوم کشاورزی، دانشگاه گیلان | ||
| 2دانش آموخته کارشناسی ارشد گروه مهندسی آب، گرایش سازه های آبی، دانشکده علوم کشاورزی، دانشگاه گیلان | ||
| 3دانشجوی گروه مهندسی آب، دانشکده علوم کشاورزی، دانشگاه گیلان | ||
| چکیده | ||
| در تحلیل احتمالاتی پدیده تحکیم خاک، نقش عدم قطعیت متغیرهای هیدرولیکی و ژئوتکنیکی و همبستگی میان مقادیر آنها از اهمیت ویژهای برخوردار است. در تحقیق حاضر، فرضیه تاثیر همبستگی متغیرهای تصادفی هدایت هیدرولیکی و ضریب قابلیت فشردگی حجمی بر تغییرات زمانی تحلیل احتمالاتی تحکیم خاک مورد بررسی قرار می گیرد. نکته حائز اهمیت این است که در صورت تائید تاثیر همبستگی متغیرهای تصادفی مورد بررسی، بررسی نقش آن ها به صورت منفرد موجب خطا در تعیین تغییرات زمانی تحکیم خاک می شود. بدین جهت در تحقیق حاضر، یک برنامه رایانهای در محیط MATLAB توسعه داده شد و از حل عددی معادله دیفرانسیل تحکیم خاک، به عنوان راه حل پایه در روش احتمالاتی شبیه سازی مونتکارلو استفاده گردید. سپس تأثیر اعمال همبستگی هدایت هیدرولیکی و ضریب قابلیت فشردگی حجمی به عنوان دو متغیر تصادفی تاثیرگذار، با استفاده از توابع کاپولا مختلف و در قالب تحلیل احتمالاتی دو متغیره تحکیم خاک در منطقه شفت استان گیلان بررسی شد. نتایج نشان داد که بهترین توزیع منفرد برازش داده شده بر هر یک از متغیرهای تصادفی مذکور، گوسی معکوس بوده در حالی که با اعمال تاثیر همبستگی، بهترین توزیع احتمالاتی مشترک از تابع کاپولا گوسی حاصل می گردد. همچنین خطای ناشی از عدم اعمال همبستگی متغیرهای تصادفی بر پدیده تحکیم، در عمق های خاک 2 و 4 متر به ترتیب 7 و 2/2 درصد به دست آمد. در انتها نتایج نشان داد که در شرایط عدم اعمال همبستگی متغیرهای تصادفی مورد بررسی در این تحقیق، سرعت پدیده تحکیم بیشتر از حالت اعمال همبستگی این متغیرها برآورد می گردد. | ||
| کلیدواژه‌ها | ||
| تحلیل احتمالاتی مشترک؛ خاک ریزدانه؛ روش مونتکارلو؛ توابع کاپولا | ||
| عنوان مقاله [English] | ||
| Bivariate probabilistic analysis of temporal variations of pore water pressure during consolidation process in structural foundation | ||
| نویسندگان [English] | ||
| Amir Malekpour1؛ Nima Sadeghian2؛ Mohammad Javad Farrokhi3 | ||
| 1Assistant Prof., Department of Water Engineering, Faculty of Agricultural Sciences, University of Guilan | ||
| 2Master's degree in water engineering department, majoring in water structures.Department of Water Engineering, Faculty of Agricultural Sciences, University of Guilan | ||
| 3Student of the water engineering department, Faculty of Agricultural Sciences, University of Guilan | ||
| چکیده [English] | ||
| Extended Abstract Introduction The consolidation and the subsequent settlement can lead to the land subsidence, building destruction, pipeline ruptures in water supply networks, and damage to the asphalt pavement. In soil consolidation analyses and many other geotechnical problems, the uncertainty of geotechnical variables and their spatial variations is of significant importance. As a result, the uncertainty-based approaches are currently employed to consider these problems rather than deterministic analyses. In this regard, some researches have demonstrated the considerable influence of the random variables of hydraulic conductivity and volume compressibility on the soil consolidation phenomenon. However, the studies have rarely addressed the correlation between these random variables and its effect on the probabilistic consolidation analysis. The current research aims at investigating the impact of correlation between two random variables of hydraulic conductivity and volume compressibility using copula functions via the development of a computer program in MATLAB. The performance of different copula functions in the bivariate probabilistic analysis of consolidation and the temporal variations of pore water pressure distributions are studied in a case study in Guilan province of Iran. Methodology In this research, a computer program was developed in MATLAB to estimate the marginal distributions of two random variables of hydraulic conductivity and soil volume compressibility. Then the bivariate probability distributions of two random variables were obtained using two copula groups of Archimedean (Clayton, Gumbel and Frank) and elliptic (Gaussian and t-student). The bivariate distributions of random variables were applied to estimate the temporal pore water pressure distributions during consolidation in soil depths of 2 and 4 meters. The best joint probability distribution and the corresponding copula function was determined on MvCAT software based on the correlation of random variables and using certain criteria such as AIC, BIC, RMSE, and NSE. As a feature of developed computer program in this research,1000 pair values of hydraulic conductivity and volumetric compressibility were generated by copula functions (from the primary 24 field data) in order to create more accurate results. Then, after numerically solving the governing differential equation of consolidation using the implicit central finite difference method, the probability distributions of pore water pressure over time including the probability density functions (PDFs) and cumulative distribution functions (CDFs) were calculated using different copulas and compared with each other. Results and Discussion The results showed that the inverse Gaussian distribution properly fits to the marginal distributions of each single random variable, according to BIC criterion. In this research, Kendall’s correlartion coefficient showed a positive correlation between the random variables of hydraulic conductivity and soil volume compressibility. After 15 days from the beginning of consolidation with an initial loading of 400 kPa, the pore water pressures in the depth of 2 meters were estimated equal to 398.75, 398.9 and 398.95 kPa for Clayton, Gumbel and Clayton copulas, respectively. Whereas the pore pressure in the same depth were obtained equal to 399 and 399.05 kPa for Gaussian and t-student copulas, respectively. In the depth of 4 meters, Clayton, Gumbel and Clayton copulas, estimated the pore pressures equal to 399.54, 399.55, 399.54 kPa, respectively. It shows that Archimedean copulas create almost similar results in deeper regions within a soil layer. For elliptical copulas in the depth of 4 meters, the pore water pressures were calculated equal to 399.8 and 399.75 kPa for Gaussian and t-student copulas, respectively. Conclusions Considering the correlation of random variables, it is concluded that Archimedean copulas are more accurate in extreme values than elliptic copulas but elliptic copulas according to AIC, BIC and other evaluation criteria provide better balance between the number of parameters, the accuracy and the complexity of model. Generally, for both Archimedean and elliptic copulas, the temporal variations of pore water distributions show an increase in uncertainty with time via changing from sharp and narrow curves to flat and wide curves. Moreover, the consolidation rate (pore pressure dissipation rate) is slower for elliptic copulas than Archimedean copulas. Gaussian copula was found to be the best copula among all investigated copulas. The error of neglecting the correlation of random variables is bigger when a shallow foundation is to be designed by an engineer. Meanwhile, the consolidation rate is overestimated when the correlation of random variables is ignored. Acknowledgement The authors express their gratitude to the experts working in technical and soil mechanics laboratory of Guilan province for their collaborations and carrying out the experiments on the soil samples of this research. | ||
| کلیدواژه‌ها [English] | ||
| Copula functions, Fine-grained soil, Joint probability analysis, Monte-Carlo method | ||
| مراجع | ||
|
Aguilar-López, J., J. Warmink, R. Schielen and S. Hulscher. (2014). Flood defence design parameters correlation influence on failure probability–case study of backward erosion piping. 3rd IAHR Europe Congress: Water-Engineering and Research, April, 2014, Porto, Portugal. pp. 1-12. Alibeikloo, M., Khabbaz, H., Fatahi, B., & Le, T. M. (2021). Reliability assessment for time-dependent behaviour of soft soils considering cross correlation between visco-plastic model parameters. Reliability Engineering & System Safety, 213, 107680. Bahrami, R., Khayat, N., & Nazarpour, A. (2021). Laboratory investigation on physical-mechanical characteristics and microstructure of a clayey gypsiferous soil in the presence of chemical accelerator. KSCE Journal of Civil Engineering, 25(9), 3273-3288. Benemaran, R. S., & Esmaeili-Falak, M. (2023). Predicting the Young's modulus of frozen sand using machine learning approaches: State-of-the-art review. Geomechanics and Engineering, 34(5), 507-527. Charoosaei, S., Khayat, N., & Adeli, M. M. (2019). Evaluation of Mathematical Relationships of Shear Wave Velocity and StandardPenetration Test Results with Bayesian Statistics Approach, Bulletin of Earthquake Science and Engineering, 6(4), 37-51. Cheng, Y., Zhang, L. L., Li, J. H., Zhang, L. M., Wang, J. H., & Wang, D. Y. (2017). Consolidation in spatially random unsaturated soils based on coupled flow‐deformation simulation. International Journal for Numerical and Analytical Methods in Geomechanics, 41(5), 682-706. Griffiths, D. V., & Fenton, G. A. (2009). Probabilistic settlement analysis by stochastic and random finite-element methods. Journal of geotechnical and geoenvironmental engineering, 135(11), 1629-1637. Khalaf-Shoushtari, M., Khayat, N., & Nazarpour, A. (2017). Investigating Parameters Affecting the Settlement of Gypsum Soils. Irrigation and Drainage Structures Engineering Research, 17(67), 81-94. Kilgore, R. T., & Thompson, D. B. (2011). Estimating joint flow probabilities at stream confluences by using copulas. Transportation research record, 2262(1), 200-206. Malekpour, A., Farookhroo, S., & Hosseini, M. (2019). Effect of Uncertainty of Soil Compressibility on Temporal Variations of Pore-Water Pressure at the Foundation of Structure. Water and Soil Science (Agricultural Science), 29(2), 199-212. (in Persian) Malekpour, A., Sadeghian, N., & Mohammadi, M. (2018). Effect of uncertainty of hydraulic conductivity and number of samples in Monte-Carlo method on time-dependent variation of soil consolidation, Iranian Journal of Soil and Water Research, 49(4), 739-749. (in Persian) Marden, J. I. (2004). Positions and QQ plots, Statistical Science, 19(4), 606-614. Nadim, F. (2015). Accounting for uncertainty and variability in geotechnical characterization of offshore sites. In Geotechnical safety and risk V (pp. 23-35). IOS Press. Nour, A., Slimani, A., & Berrah, M. K. (2007). Consolidation statistics investigation via thin layer method analysis. Transport in porous media, 67(1), 69-91. Sadegh, M., Ragno, E., & AghaKouchak, A. (2017). Multivariate Copula Analysis Toolbox (MvCAT): describing dependence and underlying uncertainty using a Bayesian framework. Water Resources Research, 53(6), 5166-5183. Sklar, M. 1959. Fonctions de repartition an dimensions et leurs marges. Publ. inst. statist. univ. Paris, 8, 229-231. Torfi, S., Khayat, N., & Horpibulsuk, S. (2021). Sustainable stabilization of compacted clay using sodium alginate for subgrade application. International Journal of Geosynthetics and Ground Engineering, 7, 1-15. Wang, L., Tang, L., Wang, Z., Liu, H., & Zhang, W. (2020). Probabilistic characterization of the soil-water retention curve and hydraulic conductivity and its application to slope reliability analysis. Computers and Geotechnics, 121, 103460. Wang, Y., Zhao, X., & Wang, B. (2013). LS-SVM and Monte Carlo methods based reliability analysis for settlement of soft clayey foundation. Journal of Rock Mechanics and Geotechnical Engineering, 5(4), 312-317. Yang, S. C., Liu, T. J., & Hong, H. P. (2017). Reliability of tower and tower-line systems under spatiotemporally varying wind or earthquake loads. Journal of Structural Engineering, 143(10), 04017137. Zhang, Y., Beer, M., & Quek, S. T. (2015). Long-term performance assessment and design of offshore structures. Computers & Structures, 154, 101-115. Zomorodian, S. M. A., Zerangsani, F. (2015). Investigation into the effect of the uncertainty of geotechnical parameters on the bearing capacity of strip footings. Sharif Journal of Civil Engineering, 31.2(1.1), 129-136. (in Persian)
| ||
|
آمار تعداد مشاهده مقاله: 164 تعداد دریافت فایل اصل مقاله: 164 |
||