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International Review of Civil Engineering - July 2012 (Vol. 3 N. 4) - Papers

Soil Property Sensitivity in Progressive Failure of Slopes

Design Solution of the Tunnel "Jurin kuk"

Monte Carlo Calculations of Energy and Drift Velocity in ZnS, ZnSe, ZnTe

A Mathematical Model for Dimensioning of Footings Square

Load-Settlement Response of Raft Foundations Enhanced by Piles

Analysis of the Behavior of Concrete Seawalls Against Earthquake and Wave Impact Loads

International Review of Civil Engineering - Papers

Soil Property Sensitivity in Progressive Failure of Slopes
by Anders S. Gylland, Murad S. Sayd, Hans Petter Jostad, Stig Bernander

Vol. 3 n. 4, pp. 321-328

Abstract - The presence of sensitive clay pose a challenge when performing slope stability assessments. Because of the strain softening behavior, the validity of conventional calculation methods based on the principle of limit equilibrium (LE) are not fully valid. This paper studies downward progressive failure in long natural slopes with an aim of identifying the governing parameters and the validity range of LE methods. A FEM approach which accounts for the non-linear stress-strain curve of the material, including the post peak softening behavior, is used. Sensitivity of the analyses to variations of key parameters like in-situ shear stress at the failure plane, brittleness, stiffness of the soil mass, and geometry are investigated in terms of critical load for initiating the slide and the corresponding critical length. The results show that the capacity of the slope in terms of external actions is reduced the steeper the slope is, the more strain softening behavior the material display and the lower stiffness the overlying soil has. The initial shear stress level is identified as a highly sensitive parameter. Further, by studying variations in the critical length it is indicated that the validity of classical LE methods is limited for steep slopes in soft and very sensitive clay.
Copyright © 2012 Praise Worthy Prize S.r.l. - All rights reserved

Keywords: Slope Stability, Strain Softening Soil, Clay, Progressive Failure.

Design Solution of the Tunnel "Jurin kuk"
by Davor Bojanić, Tatjana Bojanić, Alen Harapin

Vol. 3 n. 4, pp. 329-340

Abstract - The main design of the tunnel "Jurin kuk" within the major road Gata-Zvečanje in Croatia, is presented in this work. The basic traffic and geometric characteristics of the tunnel are given, and the design solution with comments about the issue of the tunnel’s construction is briefly presented. Some expected characteristics of the rock mass and excavation methods, as well as the type of support, which are adopted in geotechnical and structural solutions, are also displayed.
Copyright © 2012 Praise Worthy Prize S.r.l. - All rights reserved

Keywords: Tunnel, Tunnel Design, Tunnel Excavation, Tunnel Drainage.

Monte Carlo Calculations of Energy and Drift Velocity in ZnS, ZnSe, ZnTe
by Siham Khedim, Boumediene Benyoucef, Nasr E. Chabane Sari

Vol. 3 n. 4, pp. 341-345

Abstract - A Monte Carlo simulation of high field electron transport in ZnS, ZnSe and ZnTe has been presented. The model includes a nonparabolic three valley of the conduction band. The simulation includes scattering mechanisms associated with acoustic, intervalley and polar optical phonons, as well as ionized impurity scattering and impact ionization. The inclusion of the second conduction band is found to have a significant impact on the energy distribution at fields above 100 KV/cm. The second conduction band is also important because of its effect on the impact ionization rate. The results of simulation which are drift velocity and average electron energy are presented and discussed.

Keywords: Transport properties, Monte Carlo method, Three valley model, Semiconductor Materials.

A Mathematical Model for Dimensioning of Footings Square
by Arnulfo Luévanos Rojas

Vol. 3 n. 4, pp. 346-350

Abstract - In the design of foundations in case specifically of reinforced concrete square footings subjected to axial load and bidirectional flexure are presented different pressures in each corner, these are exerted for the floor. In this paper is developed a mathematical model to obtain the most economical dimension of the contact surface in square footings, when is applying the load that must support said structural member. The classical model is developed by trial and error, i.e., it is proposed a dimension, and using the formulates of the bidirectional flexure for to obtain the stresses acting on the four corners of the square footing, which must meet the following conditions: 1) The minimum stress should be equal to or greater than zero, because the soil is not capable of withstand tensile stresses. 2) The maximum stress must be equal or less than the allowable capacity that can withstand the ground. Therefore normal practice to use the classic model will not be a recommended solution. Then, it is best to use the proposed model since it is more economic.
Copyright © 2012 Praise Worthy Prize S.r.l. - All rights reserved

Keywords: Square Footings, Permissible Capacity of Soil, Contact Surface, more Economical Dimension, Flexure Bidirectional.

Load-Settlement Response of Raft Foundations Enhanced by Piles
by Baleshwar Singh, Sandeep Rai

Vol. 3 n. 4, pp. 351-358

Abstract - A raft foundation transmits load directly to the ground. When fully loaded, it is possible that the raft alone cannot satisfy both bearing capacity and settlement criteria. The introduction of piles enhances the load carrying capacity, and at the same time the settlement of the plain raft will be reduced. The objective of this study is to understand the overall response of the hybrid foundation system consisting of a raft and piles working together, and to examine the influence of various parameters on the foundation behavior. The parameters include dimensions of raft; pile diameter, length and spacing; Young’s modulus of raft, pile and soil; and Poisson’s ratio of raft and soil.
Copyright © 2012 Praise Worthy Prize S.r.l. - All rights reserved

Keywords: Raft Foundation, Piles, Settlement Behavior, Load Capacity, Parametric Study.

Analysis of the Behavior of Concrete Seawalls Against Earthquake and Wave Impact Loads
by M. A. Mehrdad, M. A. L. Neshaei, M. Massah Fard

Vol. 3 n. 4, pp. 359-370

Abstract - Seawalls are commonly constructed to prevent landward erosion of shorelines and maintain configuration of the area behind them against wave action. Recently, rising of sea level, particularly in the northern coastline of Iran, has attracted considerable attention of researchers to design and construction of seawalls in that region. The impact force resulting from sea waves is one of the main factors in destruction of seawalls. The present study is aimed to analyze two concrete seawalls under different loading conditions; earthquake force and wave impact loads as dynamic loadings and also hydrodynamic force as a determinant static loading on seawalls. From the simulations, displacements and Von mises stresses at the critical points of structures are obtained. The effect of wave impact load on the wall and the resulting displacements have also been explored. According to generated results at the critical points of structures such as crest and toe, higher sensitivity to wave impact loads is observed near the sea level and the crest of the seawall. Comparing the results of semi static and dynamic analysis, it further observed that dynamic analysis demonstrated significant effect of wave impact load on the results than that of static one, as the earthquake force is applied.
Copyright © 2012 Praise Worthy Prize S.r.l. - All rights reserved

Keywords: Seawall, Wave Impact Load, Earthquake Force, Von Mises Stress, Displacement.