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CONTENTS
Volume 33, Number 5, June10 2023
 

Abstract
The objective of this work is to study the wave propagation of an FGM plate via a new integral inverse shear model with temperature-dependent material properties. In this contribution, a new model based on a high-order theory field of displacement is included by introducing indeterminate integral variables and inverse co-tangential functions for the presentation of shear stress. The temperature-dependent properties of the FGM plate are assumed mixture of metal and ceramic, and its properties change by the power functions of the thickness of the plate. By applying Hamilton's principle, general formulas of wave propagation were obtained to plot the phase velocity curves and wave modes of the FGM plate with simply supported edges. The effects of the temperature and volume fraction by distributions on wave propagation of the FGM plate are investigated in detail. The results of the dispersion and the phase velocity curves of the propagation wave in the functionally graded plate are compared with previous research.

Key Words
FGM plate; new integral inverse shear model; temperature-dependent material properties; wave propagation

Address
Mokhtar Ellali: Smart Structures Laboratory, University of Ain Témouchent-Belhadj Bouchaib,46000,Algeria
Mokhtar Bouazza: Department of Civil Engineering, University Tahri Mohamed of Bechar, Bechar 08000, Algeria;
Laboratory of Materials and Hydrology (LMH), University of Sidi Bel Abbes, Sidi Bel Abbes 22000, Algeria
Ashraf M. Zenkour: Department of Mathematics, Faculty of Science, King Abdulaziz University,
P.O. Box 80203, Jeddah 21589, Saudi Arabia;
Department of Mathematics, Faculty of Science, Kafrelsheikh University, Kafrelsheikh 33516, Egypt

Abstract
The construction of shield tunnelling in urban sites is facing serious risks from complex and changeable underground conditions. Construction problems in the sand-clay mixed ground have been more reported in recent decades for its poor control of soil loss in tunnel face, ground settlement and supporting pressure. Since the limitations of observation methods, the conventional physical modelling experiments normally simplify the tunnelling to a plane strain situation whose results are not reliable in mixed ground cases which exhibit more complicated responses. We propose a new method for the study of the mixed ground tunnel through which mixed lays are simulated with transparent soil surrogates exhibiting different mechanical properties. An experimental framework for the transparent soil modelling of the mixed ground tunnel was established incorporated with the self-developed digital image correlation system (PhotoInfor). To understand better the response of face stability, ground deformation, settlement and supporting phenomenon to tunnelling excavation in the sand-clay mixed ground, a series of case studies were carried out comparing the results from cases subjected to different buried depths and mixed phenomenon. The results indicate that the deformation mode, settlement and supporting phenomenon vary with the mixed phenomenon and buried depth. Moreover, a stratigraphic effect exists that the ground movement around mixed face reveals a notable difference.

Key Words
digital image correlation; face stability; modelling experiment; sand-clay mixed ground; shield tunnel; transparent soil

Address
YuanHai Li, XiaoJie Tang and YanFeng Ding: State Key Laboratory for Geomechanics and Deep Underground Engineering, Xuzhou, China;
School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, China
Shuo Yang: School of Civil Engineering, Xuzhou University of Technology, Xuzhou, China



Abstract
Intermediate Geomaterials (IGMs) are natural formation materials that exhibit the engineering behavior (strength and compressibility) between soils and rocks. The engineering behavior of such material is highly unpredictable as the IGMs are stiffer than soils and weaker/softer than rocks. Further, the characterization of such material needs exposure to both soil and rock mechanics. In most conventional designs of geotechnical structures, the engineering properties of the IGMs are either aligned with soils or rocks, and this assumption may end up either in an over-conservative design or under-conservative design. Hence, many researchers have attempted to evaluate its actual engineering properties through laboratory tests. However, the test results are partially reliable due to the poor core recovery of IGMs and the possible sample disturbance. Subsequently, in-situ tests have been used in recent years to evaluate the engineering properties of IGMs. However, the respective in-situ test finds its limitations while exploring IGMs with different geological formations at deeper depths with the constraints of sampling. Standard Penetration Test (SPT) is the strength-based index test that is often used to explore IGMs. Moreover, it was also observed that the coefficient of variation of the design parameters (which represents the uncertainties in the design parameters) of IGMs is relatively high, and also the studies on the probabilistic characterization of IGMs are limited compared with soils and rocks. With this perspective, the present article reviews the laboratory and in-situ tests used to characterize the IGMs and explores the shear strength variation based on their geological origin.

Key Words
heavily overconsolidated clay; indurated soil; probabilistic characterization; residual soil; soft rock

Address
T. Ashok Kumar: Department of Civil Engineering, National Institute of Technology Puducherry, Karaikal-609609, India
Ramanandan Saseendran: Department of Civil Engineering, Indian Institute of Technology Madras, Chennai-600036, India
V. Sundaravel: TechnipFMC, Chennai, India

Abstract
Tunnel construction activity, conducted mainly in mountains and within urban centres, causes soil settlement, thus requiring the relevant management of slopes and structures as well as evaluations of risk and stability. Accordingly, in this study we performed a three-dimensional finite element analysis to examine the behaviour of piles and pile cap stability when a tunnel passes near the bottom of the foundation of a pile group connected by a pile cap. We examined the results via numerical analysis considering different conditions for reinforcement of the ground between the tunnel and the pile foundation. The numerical analysis assessed the angular distortion of the pile cap, pile settlement, axial force, shear stress, relative displacement, and volume loss due to tunnel excavation, and pile cap stability was evaluated based on Son and Cording's evaluation criterion for damage to adjacent structures. The pile located closest to the tunnel under the condition of no ground reinforcement exhibited pile head settlement approximately 70% greater than that of the pile located farthest from the tunnel under the condition of greatest ground reinforcement. Additionally, pile head settlement was greatest when the largest volume loss occurred, being approximately 18% greater than pile head settlement under the condition having the smallest volume loss. This paper closely examines the main factors influencing the behaviour of a pile group connected by a pile cap for three ground reinforcement conditions and presents an evaluation of pile cap stability.

Key Words
ground reinforcement; pile group; stability evaluation; three-dimensional numerical analysis; tunnel construction

Address
Young-Jin Jeon: College Institute of Industrial Technology, Kangwon National University, 1 Kangwondaehak-gil,
Chuncheon-si, Gangwon-do, Republic of Korea
Cheol-Ju Lee: Department of Civil Engineering, Kangwon National University, 1 Kangwondaehak-gil,
Chuncheon-si, Gangwon-do, Republic of Korea

Abstract
In the studies on fault dislocation of tunnel, existing literatures are mainly focused on the problems caused by normal and reverse faults, but few on strike-slip faults. The paper aims to research the deformation and failure mechanism of a tunnel under strike-slip faulting based on a model test and test-calibrated numerical simulation. A potential faulting hazard condition is considered for a real water tunnel in central Yunnan, China. Based on the faulting hazard to tunnel, laboratory model tests were conducted with a test apparatus that specially designed for strike-slip faults. Then, to verify the results obtained from the model test, a finite element model was built. By comparison, the numerical results agree with tested ones well. The results indicated that most of the shear deformation and damage would appear within fault fracture zone. The tunnel exhibited a horizontal S-shaped deformation profile under strike-slip faulting. The side walls of the tunnel mainly experience tension and compression strain state, while the roof and floor of the tunnel would be in a shear state. Circular cracks on tunnel near fault fracture zone were more significant owing to shear effects of strike-slip faulting, while the longitudinal cracks occurred at the hanging wall.

Key Words
deformation profile; failure pattern; strain distribution features; strike-slip fault; water conveyance tunnel

Address
Zhen Cui, Qian Sheng and Guangxin Zhou: State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics,
Chinese Academy of Sciences, Wuhan, Hubei 430071, China
Tianqiang Wang: Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, School of Civil Engineering,
Southwest Jiaotong University, Chengdu, 610031, China

Abstract
Looking from the past to the present, the earthquakes can be said to be type of disaster with most casualties among natural disasters. Soil liquefaction, which occurs under repeated loads such as earthquakes, plays a major role in these casualties. In this study, analytical equation models were developed to predict the probability of occurrence of soil liquefaction. In this context, the parameters effective in liquefaction were determined out of 170 data sets taken from the real field conditions of past earthquakes, using WEKA decision tree. Linear, Exponential, Power and Quadratic models have been developed based on the identified earthquake and ground parameters using Krill Herd algorithm. The Exponential model, among the models including the magnitude of the earthquake, fine grain ratio, effective stress, standard penetration test impact number and maximum ground acceleration parameters, gave the most successful results in predicting the fields with and without the occurrence of liquefaction. This proposed model enables the researchers to predict the liquefaction potential of the soil in advance according to different earthquake scenarios. In this context, measures can be realized in regions with the high potential of liquefaction and these measures can significantly reduce the casualties in the event of a new earthquake.

Key Words
earthquake; Krill Herd algorithm; optimization; soil liquefaction; structural damage

Address
Yetis Bulent Sonmezer and Ersin Korkmaz: Department of Civil Engineering, Engineering Faculty, Kirikkale University, 71451 Kirikkale, Turkey

Abstract
The effects of various supporting arrangements have been investigated on an excavation support system using a numerical tool. The purpose of providing different supporting arrangements was to limit the pile wall deflection in the range of 0.5% to 1% of the excavation depth. Firstly, a deep excavation supported by sheet pile wall was modeled and the effects of sheet pile wall thickness, excavation depth and distance to adjacent footings from sheet pile wall face were explored on the soil deformation and wall deflection. Further analysis was performed considering six different arrangements of tieback anchors and struts in order to limit the wall deflections. Case-01 represents the basic excavation geometry supported by sheet pile wall only. In Case-02, sheet pile wall was supported by struts. Case-03 is a sheet pile wall supported by tieback anchors. Likewise, for the Cases 04, 05 and 06, different arrangements of struts and tieback anchors were used. Finally, the effects of different supporting arrangements on soil deformation, sheet pile wall deflection, bending moments and anchor forces have been presented.

Key Words
deep excavation; excavation support system; FEM analysis; struts; tieback anchors

Address
Ali Murtaza Rasool:National Engineering Services Pakistan (NESPAK), Lahore, Pakistan;
University of Central Punjab, Lahore, Pakistan;
National College of Arts, Lahore, Pakistan
Fawad S. Niazi: Department of Civil and Mechanical Engineering, Purdue University, Fort Wayne, IN, USA
Tauqir Ahmed: Department of Civil Engineering, National University of Computer and Emerging Sciences, Lahore, Pakistan
Mubashir Aziz: Department of Civil and Environmental Engineering, King Fahd University of Petroleum and Minerals, Dhahran, KSA;
Interdisciplinary Research Center for Construction and Building Materials,
King Fahd University of Petroleum and Minerals, Dhahran, KSA

Abstract
In this paper, we present the results of an experimental study on the effect of polymer support fluid on shaft resistance of offshore bored piles. A series of pullout tests were performed on bored piles installed under various boundary conditions considering different types of grounds and support fluids, and a range of support fluid exposure times. Contrary to previous studies concerning onshore bored piles, a time dependent effect of polymer fluid on shaft resistance was observed in all ground types. The adverse effect of polymer support fluid on the shaft resistance, however, was considerably less than bentonite support fluid for a given exposure time. No significant reduction in shaft resistance was evident when limiting the exposure time of the polymer support fluid to the side wall of the borehole within 2-3 hours. The degree to which the polymer fluid affects shaft resistance seemed to vary with the ground type. A proper consideration should be given to the time dependent effect of polymer fluid on shaft resistance of bored piles installed in offshore construction environment to limit its adverse effect on the pile performance. The practical implications of the findings are discussed.

Key Words
bentonite; bored pile; filter cake; offshore pile construction; polymer; shaft resistance; support fluid

Address
Chungsik Yoo and Chun-Won Shin: School of Civil, Architectural Engineering and Landscape Architecture, Sungkyunkwan University,
2066 Seboo-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Republic of Korea

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