Abstract
Uplift response of symmetrical circular anchor plates has been evaluated in physical model tests and numerical simulation using Plaxis. The behavior of circular anchor plates during uplift test was studied by experimental data and finite element analyses in loose sand. Validation of the analysis model was also carried out with 50 mm, 75 mm and 100 mm diameter of circular plates in loose sand. Agreement between the uplift responses from the physical model tests and finite element modeling using PLAXIS 2D, based on 100 mm computed maximum displacements was excellent for circular anchor plates. Numerical analysis using circular anchor plates was conducted based on hardening soil model (HSM). The research has showed that the finite element results gives higher than the experimental findings in the loose sand.
Key Words
uplift response; symmetrical anchor plate; circular plate; loose sand; numerical modelling; plaxis; FEM; Hardening Soil Model (HSM)
Address
Hamed Niroumand and Khairul Anuar Kassim:
Department of Geotechnical Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, Jalan Iman, 81300 Skudai, Johor Bahru, Malaysia.
Abstract
Uplift response of rectangular anchor plates has been investigated in physical model tests and numerical simulation using Plaxis. The behavior of rectangular plates during uplift test was studied by experimental data and finite element analyses in cohesionless soil. Validation of the analysis model was also carried out with 200 mm and 300 mm diameter of rectangular plates in sand. Agreement between the uplift responses from the physical model tests and finite element modeling using PLAXIS 2D, based on 200 mm and 300 mm computed maximum displacements were excellent for rectangular anchor plates. Numerical analysis using rectangular anchor plates was conducted based on hardening soil model (HSM). The research has showed that the finite element results gives higher than the experimental findings in dense and loose packing of cohesionless soil.
Key Words
uplift response; symmetrical anchor plate; rectangular plate; cohesionless soil; numerical modeling; Plaxis; FEM; Hardening Soil Model (HSM)
Address
Hamed Niroumand and Khairul Anuar Kassim:
Department of Geotechnical Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, Jalan Iman, 81300 Skudai, Johor Bahru, Malaysia.
Abstract
Thermal conductivity of ground has a great influence on the performance of Ground Heat Exchangers (GHEs). In general, the ground thermal conductivity significantly depends on the density (or porosity) and the moisture content since they are decisive factors that determine the interface area between soil particles which is available for heat transfer. In this study, a large number of thermal conductivity experiments were conducted for soils of varying porosity and moisture content, and a database of thermal properties for the weathered granite soils was set up. Based on the database, a 3D Curved Surface Model and an Artificial Neural Network Model (ANNM) were proposed for estimating the thermal conductivity. The new models were validated by comparing predictions by the models with new thermal conductivity data, which had not been used in developing the models. As for the 3D CSM, the normalized average values of training and test data were 1.079 and 1.061 with variations of 0.158 and 0.148, respectively. The predictions became somewhat unreliable in a low range of thermal conductivity values in considering the distribution pattern. As for the ANNM, the
Key Words
thermal conductivity; predictive model; artificial neural network model; transfer function; weathered granite soils
Address
(1) Gyu-Hyun Go, Seung-Rae Lee and Seok Yoon:
Department of Civil Engineering, Korean Advanced Institute for Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea;
(2) Young-Sang Kim:
Department of Marine and Civil Engineering, Chonnam National University, 50 Daehak-ro, Yeosu, Jeonnam 550-749, Republic of Korea;
(3) Hyun-Ku Park:
Engineering & Construction Group Civil Engineering Division, Samsung C&T, 1321-20 Seocho 2-Dong, Seocho-Gu, Seoul 137-857, Republic of Korea.
Abstract
The vacuum consolidation method which was proposed by Kjellman in 1952 has been studied extensively and used successfully since early 1980 throughout the world, especially in East and Southeast Asia. Despite the increased successful use, different opinions still exist, especially in connection to distribution of vacuum with depth and time in vertical drains and in soil during preloading of soft ground. Porewater pressure measurements from actual cases of field vacuum and vacuum-fill preloading as well as laboratory studies have been examined. It is concluded that (a) a vacuum magnitude equal to that in the drainage blanket remains constant with depth and time within the vertical drains, (b) as expected, vacuum does not develop at the same rate within the soil at different depths; however, under ideal conditions vacuum is expected to become constant with depth in soil after the end of primary consolidation, and (c) there exists a possibility of internal leakage in vacuum intensity at some sublayers of a soft clay and silt deposit. A case history of vacuum loading with sufficient subsurface information is analyzed using the ILLICON procedure.
Key Words
vacuum consolidation; vacuum pressure distribution; preloading; ground improveme
Address
(1) Abdul Qudoos Khan:
National University of Sciences and Technology, H-12, Islamabad, Pakistan;
(2) G. Mesri:
University of Illinois at Urbana-Champaign, USA.
Abstract
In an attempt to make a numerical modeling of the nailed walls with a view to assess the stability has been used. A convenient modeling which can provide answers to nearly situ conditions is of particular significance and can significantly reduce operating costs and avoid the risks arising from inefficient design. In the present study, a nailing system with a excavation depth of 8 meters has been modeled and observed by using the three constitutive behavioral methods; Mohr Coulomb (MC), hardening soil (HS) and hardening soil model with Small-Strain stiffness ensued from small strains (HSS). There is a little difference between factor of safety and the forces predicted by the three models. As extremely small lateral deformations exert effect on stability and the overall deformation of a system, the application of advanced soil model is essential. Likewise, behavioral models such as HS and HSS realize lower amounts of the heave of excavation bed and lateral deformation than MC model.
Key Words
soil nail walls; MC model; HS model; HSS model; PLAXIS 2D
Address
(1) Alireza Ardakani:
Faculty of Engineering and Technology, Imam Khomeini International University, Qazvin, Iran;
(2) Mahdi Bayat:
Department of Civil Engineering, College of Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran;
(3) Mehran Javanmard:
Department of Civil Engineering, University of Zanjan, Zanjan, Iran.
Abstract
There are around 6700 millions tons of perlite reserves in the world. Although perlite possesses pozzolanic properties, it has not been so far used in soil stabilization. In this study, stabilization with perlite and lime of an expansive clayey soil containing smectite group clay minerals such as montmorillonite and nontronite was investigated experimentally. For this purpose, test mixtures were prepared with 8% of lime (optimum lime ratio of the soil) and without lime by adding 0%, 10%, 20%, 30%, 40% and 50% of perlite. Geotechnical properties such as compaction, Atterberg limits, swelling, unconfined compressive strength of the mixtures and changes of these properties depending on perlite ratio and time were determined. The test results show that stabilization of the soil with combination of perlite and lime improves the geotechnical properties better than those of perlite or lime alone. This experimental study unveils that the mixture containing 30% perlite and 8% lime is the optimum solution in stabilization of the soil with respect to strength.
Key Words
soil stabilization; natural pozzolan; perlite; lime; pozzolanic reaction
Address
(1) Umit Calik:
General Directorate of Highways: 10th Regional Directorate, 61310 Akcaabat-Trabzon, Turkey:
(2) Erol Sadoglu:
Department of Civil Engineering, Karadeniz Technical University, 61080 Trabzon, Turkey.
