Verification of soil parameters of hardening soil model with small-strain stiffness for deep excavations in medium dense sand in Ho Chi Minh City, Vietnam

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Quoc Thien Huynh ◽  
Van Qui Lai ◽  
Tirawat Boonyatee ◽  
Suraparb Keawsawasvong
Author(s):  
Katarzyna Markowska-Lech ◽  
Wojciech Sas ◽  
Mariusz Lech ◽  
Katarzyna Gabryś ◽  
Alojzy Szymański

Abstract The shear modulus of soils at small strain (G0) is one of the input parameters in a finite element analysis with the hardening soil model with small strain stiffness, required in the advanced numerical analyses of geotechnical engineering problems. The small strain stiffness can be determined based on the seismic wave velocities measured in the laboratory and field tests, but the interpretation of test results is still under discussion because of many different factors affecting the measurements of the wave travel time. The recommendations and proposed solutions found in the literature are helpful as a guide, but ought to be adopted with a certain measure of care and caution on a case-by-case basis. The equipment, procedures, tests results and interpretation analyses of bender elements (BE) tests performed on natural overconsolidated cohesive soils are presented.


Author(s):  
Георгий Владимирович Мосолов ◽  
Илья Леонидович Димов

Уже в ближайшем будущем от использования современных численных методов расчета будет зависеть прогресс в области проектирования оснований и фундаментов зданий и сооружений, поскольку возможности по совершенствованию строительных норм практически исчерпаны. Целью статьи является демонстрация возможностей численных расчетов с использованием современных моделей грунта на примере проектирования фундамента стандартного нефтяного резервуара для хранения нефти и нефтепродуктов. Приведено сравнение результатов расчетов осадки основания резервуара емкостью 30 000 м, выполненных в соответствии с действующими нормами проектирования и методом конечных элементов с применением программного комплекса PLAXIS. В частности, проведены численные расчеты с использованием современных моделей грунта: 1) модели грунта с упрочнением (Hardening Soil model, HS); 2) модели грунта с упрочнением и учетом малых деформаций (Hardening Soil small strain model, HSs). Показано, что использование указанных моделей при наличии требуемого объема исходных данных позволяет существенно уточнить вычисления, выполняемые по нормативным методикам. С учетом полученных результатов определена возможность оптимизации проектных решений при выборе типа фундамента резервуара. In the near future, the progress in design of bases and foundations of buildings and structures will depend on the use of modern numerical calculation methods since the opportunities to improve the building regulations are almost exhausted. This article aims to demonstrate the capabilities of numerical calculations with the use of modern soil models on the example of designing the foundation of a standard oil storage tank for crude oil and petroleum products. This article provides a comparison of the results of the base settlement of a 30,000 m tank calculations made in accordance with the current standards of design and the finite elements method with the use of the PLAXIS software package. In particular, the following numerical calculations with the use of modern soil models have been performed: 1) Hardening Soil model, HS; 2) Hardening Soil small strain model, HSs. It is shown that the use of these models in the presence of the required amount of baseline data can significantly refine the calculations performed according to normative methods. Considering the obtained results, the possibility of optimizing design solutions when selecting the type of foundation of a tank was determined.


Author(s):  
Katarzyna Markowska-Lech ◽  
Mariusz Lech ◽  
Marek Bajda ◽  
Alojzy Szymański

Abstract Small strain stiffness in overconsolidated Pliocene clays. A huge development of technical infrastructure, including the construction of many high-rise buildings, roads, railroads and extension of subway lines, took place over the recent years in Poland. Therefore, numerous planned investment projects require geotechnical data documenting the variation of soil parameters found in the subsoil. The shear wave velocity is one of the most important input parameters to represent the stiffness of the soil deposits. This paper focuses on the methods and devices using measurements of the shear wave velocity to estimate the initial shear modulus in cohesive soil. It is preferable to measure VS by in situ wave propagation tests, however it is often economically not feasible in all regions of Poland. Hence, a reliable correlation between shear wave velocity and parameters measured in triaxial cell or static penetration parameters would be a considerable advantage. This study shows results obtained from the bender elements tests and field techniques - seismic cone penetration test and seismic flat dilatometer, performed on overconsolidated cohesive soils in Warsaw. On the basis of the test results possible correlations between shear wave velocity (initial shear modulus), mean effective stress and void ratio are considered and four original empirical relationships are proposed. Moreover, the proposed formulas by two different techniques using triaxial apparatus and also RCPT cone were examined. The proposed formulas show a reasonable agreement with direct shear wave velocity profiles for clays and might be incorporated into routine laboratory and field practice


Author(s):  
Jeremy T. Bowers ◽  
Mark C. Webb ◽  
Jesse L. Beaver

The design and analysis of buried structures presents difficulties that cannot often be solved by closed-form solutions. Finite element methods (FEM) have increasingly become the tool of choice for advanced soil-structure interaction analysis, with three-dimensional FEM being required for irregular non-plane-strain cases. To accurately capture the stress and deformation of soils, complex material constitutive models are required. Several input parameters to these models must be determined from expensive soil testing, which is impractical for most applications. For two-dimensional FEM, good approximations of these parameters for a wide range of placed backfill soils have been developed and used in practice for many years in the computer program CANDE. It is the purpose of this paper to take these parameters, developed by Selig for use in CANDE, and convert them to equivalent parameters for the three-dimensional PLAXIS computer program’s Hardening Soil model.


2020 ◽  
Vol 15 (8) ◽  
pp. 2031-2051 ◽  
Author(s):  
Marcin Cudny ◽  
Andrzej Truty

2009 ◽  
Vol 49 (4) ◽  
pp. 545-556 ◽  
Author(s):  
Junhwan Lee ◽  
Doohyun Kyung ◽  
Bumjoo Kim ◽  
Monica Prezzi

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