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CONTENTS
Volume 35, Number 5, December10 2023
 

Abstract
The higher order shear deformable model and an exact analytical method is used for analytical bending analysis of a cylindrical shell subjected to mechanical loads, in this work. The shell is modelled using sinusoidal bivariate shear strain theory, and the static governing equations are derived using changes in virtual work. The eigenvalue-eigenvector method is used to exactly solve the governing equations for a constrained cylindrical shell The proposed kinematic relation decomposes the radial displacement into bending, shearing and stretching functions. The main advantage of the method presented in this work is the study of the effect of clamping constraints on the local stresses at the ends. Stress, strain, and deformation analysis of shells through thickness and length.

Key Words
clamped-clamped cylindrical pressure vessel; shear deformable model; stress/strain analyses; thickness stretching; virtual work principle

Address
Yuhao Yang: Guangzhou Sport University, Guangzhou 510630, Guangdong, China
Mohammad Arefi: Faculty of Mechanical Engineering, Department of Solid Mechanics, University of Kashan, Kashan 87317-51167, Iran

Abstract
Ballast particles have an irregular shape and are discrete in nature. Due to the discrete nature of ballast, it exhibits complex mechanical behaviour under loading conditions. The discrete element method (DEM) can model the behaviour of discrete particles under a multitude of loading conditions. DEM is used in this paper to simulate a series of three-dimensional direct shear tests in order to investigate the shear behaviour of railway ballast and its interaction at the microscopic level. Particle flow code in three dimension (PFC3D) models the irregular shape of ballast particles as clump particles. To investigate the influence of particle size distribution (PSD), real PSD of Indian railway ballast specification IRS:GE:1:2004, China high-speed rail (HSR) and French rail specifications are generated. PFC3D built-in linear contact model is used to simulate the interaction of ballast particles under various normal stresses, shearing rate and shear box sizes. The results indicate how shear resistance and volumetric changes in ballast assembly are affected by normal stress, shearing rate, PSD and shear box size. In addition to macroscopic behaviour, DEM represents the microscopic behaviour of ballast particles in the form of particle displacement at different stages of the shearing process.

Key Words
dilation angle; direct shear test; normal stress; particle displacement; particle size distribution; shear box

Address
Md Hussain: Department of Civil and Environmental Engineering, Indian Institute of Technology Patna, Bihar-801106, India;
Department of Civil Engineering, Saharsa College of Engineering, Saharsa, Bihar-852201, India
Syed Khaja Karimullah Hussaini: Department of Civil and Environmental Engineering, Indian Institute of Technology Patna, Bihar-801106, India

Abstract
Penetration rate (PR) and penetration depth (Pe) are crucial parameters for estimating the cost and time required in tunnel construction using tunnel boring machines (TBMs). This study focuses on investigating the impact of rock strength on PR and Pe through full-scale experiments. By conducting controlled tests on rock-like specimens, the study aims to understand the contributions of various ground parameters and machine-operating conditions to TBM excavation performance. An earth pressure balanced (EPB) TBM with a sectional diameter of 3.54 m was utilized in the experiments. The TBM excavated rock-like specimens with varying uniaxial compressive strength (UCS), while the thrust and cutterhead rotational speed were controlled. The results highlight the significance of the interplay between thrust, cutterhead speed, and rock strength (UCS) in determining Pe. In high UCS conditions exceeding 70 MPa, thrust plays a vital role in enhancing Pe as hard rock requires a greater thrust force for excavation. Conversely, in medium-to-low UCS conditions less than 50 MPa, thrust has a weak relationship with Pe, and Pe becomes directly proportional to the cutterhead rotational speed. Furthermore, a strong correlation was observed between Pe and cutterhead torque with a determination coefficient of 0.84. Based on these findings, a predictive model for Pe is proposed, incorporating thrust, TBM diameter, number of disc cutters, and UCS. This model offers a practical tool for estimating Pe in different excavation scenarios. The study presents unprecedented full-scale TBM excavation results, with well-controlled experiments, shedding light on the interplay between rock strength, TBM operational variables, and excavation performance. These insights are valuable for optimizing TBM excavation in grounds with varying strengths and operational conditions.

Key Words
penetration depth; rock-like material; TBM; tunnelling; UCS

Address
Gi-Jun Lee: Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong gu, Daejeon, Republic of Korea
Hee-Hwan Ryu: Korea Electric Power Research Institute (KEPRI), Daejeon, 34056, Republic of Korea
Gye-Chun Cho and Tae-Hyuk Kwon: Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST),Daejeon, 34141, Republic of Korea


Abstract
The objective of this study is to perform outlier analysis to obtain the distribution of groundwater levels through the best model. The groundwater levels are measured in 10, 25 and 30 piezometers in Seoul, Daejeon and Suncheon in South Korea. Fifty-eight empirical distribution functions were applied to determine a suitable fit for the measured groundwater levels. The best fitted models based on the measured values are determined as the Generalized Pareto distribution, the Johnson SB distribution and the Normal distribution for Seoul, Daejeon and Suncheon, respectively; the reliability is estimated through the Anderson-Darling method. In this study, to choose the appropriate confidence interval, the relationship between the amount of outlier data and the confidence level is demonstrated, and then the 95% is selected at a reasonable confidence level. The best model shows a smaller error ratio than the GEV while the Mahalanobis distance and outlier labelling methods results are compared and validated. The outlier labelling and Mahalanobis distance based on median shown higher validated error ratios compared to their mean equivalent suggesting, the methods sensitivity to data structure.

Key Words
error ratio; GEV model; goodness of fit; groundwater level; mahalanobis distance; test statistic

Address
Dae-Hong Min and Hyung-Koo Yoon: Department of Construction and Disaster Prevention Engineering, Daejeon University, Daejeon 34520, Republic of Korea
Saheed Mayowa Taiwo: Infrastructure Group, Manawatu District Council, 4743 Feilding, Palmerston North, New Zealand
Junghee Park: Department of Civil, Environmental Engineering, Incheon national University, Incheon, 22012, Republic of Korea
Junghee Park: Department of Geotechnical Engineering Research, Korea Institute of Civil Engineering and Building Technology, Republic of Korea

Abstract
Canal-side roads frequently collapse due to an unexpectedly greater soft-clay thickness with a rapid drawdown situation. This causes annually increased repair and reconstruction costs. This paper aims to explore the effect of soft-clay thickness on the failure in the canal-side road in the case study of Phra Nakhon Si Ayutthaya rural road no. 1043 (AY. 1043). Before the actual construction, a field vane shear test was performed to determine the undrained shear strength and identify the thickness of the soft clay at the AY. 1043 area. After establishing the usability of AY. 1043, the resistivity survey method was used to evaluate the thickness of the soft clay layer at the failure zone. The screw driving sounding test was used to evaluate the undrained shear strength for the road structure with a medium-stiff clay layer at the failure zone for applying to the numerical model. This model was simulated to confirm the effect of soft-clay thickness on the failure of the canal-side road. The monitoring and testing results showed the tendency of rapid drawdown failure when the canal-side road was located on > 9 m thick of soft clay with a sensitivity > 4.5. The result indicates that the combination of resistivity survey and field vane shear test can be successfully used to inspect the soft-clay thickness and sensitivity before construction. The preliminary design for preventing failure or improving the stability of the canal-side road should be considered before construction under the critical thickness and sensitivity values of the soft clay.

Key Words
sensitive clay; slope stability; soft clay thickness; rapid drawdown; road collapse

Address
Salisa Chaiyaput: Department of Civil Engineering, School of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand
Taweephong Suksawat: Bureau of Testing, Research and Development, Department of Rural Roads, Bangkok 10220, Thailand
Lindung Zalbuin Mase: Department of Civil Engineering, Faculty of Engineering, University of Bengkulu, Bengkulu 38371, Indonesia
Motohiro Sugiyama: Department of Civil Engineering, School of Architecture and Urban Planning, Tokai University, Hiratsuka Kanagawa 259-1292, Japan
Jiratchaya Ayawanna: School of Ceramic Engineering, Institute of Engineering, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand

Abstract
The development of a city is closely linked to the construction and operation of its subway system. However, constructing a new subway tunnel under an existing station is an extremely complex task, and the deformation characteristics and mechanical behavior of the new subway tunnel during the excavation process can greatly impact the normal operation of the existing station. Although the previous studies about the case of underpass engineering have been carried out, there is limited research on the condition of a newly-built subway tunnel that closely undercrossing an existing station with zero distance between them. Therefore, this study analyzes the deformation law and mechanical behavior characteristics of the preliminary lining of the underpass tunnel during the excavation process based on the real engineering case of Chengdu Metro Line 8. This study also makes an in-depth comparison of the influence of different excavation methods on this issue. Finally, the accuracy of numerical simulation is verified by comparing it with on-site result. The results indicate that the maximum bending moment mainly occurs at the floor slab of the preliminary lining, while that of the ceiling is small. The stress state at the ceiling position is less affected by the construction process of the pilot tunnel. Compared to the all-in-one excavation method, although the process of partial excavation method is more complicated, the deformation of preliminary lining caused by it is basically less than the upper limit value of the standard, while that of the all-in-one excavation method is beyond standard requirements.

Key Words
deformation law; mechanical behavior; preliminary lining; process correlation; undercrossing

Address
Huijian Zhang, Gongning Liu, Weixiong Liu, Shuai Zhang and Zekun Chen:School of Civil Engineering, Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, Southwest Jiaotong University,
No. 111, North Section, Second Ring Road, Jinniu District, Chengdu, Sichuan Province, 610031, China

Abstract
This article is dedicated to the pursuit of establishing a robust empirical relationship that allows for the estimation of in-situ modulus of deformations (Em and Gm) within sedimentary rock slope masses through the utilization of Qslope values. To achieve this significant objective, an expansive and thorough methodology is employed, encompassing a comprehensive field survey, meticulous sample collection, and rigorous laboratory testing. The study sources a total of 26 specimens from five distinct locations within the South Pars (known as Assalouyeh) region, ensuring a representative dataset for robust correlations. The results of this extensive analysis reveal compelling empirical connections between Em, geomechanical characteristics of the rock mass, and the calculated Qslope values. Specifically, these relationships are expressed as follows: Em = 2.859 Qslope + 4.628 (R2 = 0.554), and Gm = 1.856 Qslope + 3.008 (R2 = 0.524). Moreover, the study unravels intriguing insights into the interplay between in-situ deformation moduli and the widely utilized Rock Mass Rating (RMR) computations, leading to the formulation of equations that facilitate predictions: RMR = 18.12 Em0.460 (R2 = 0.798) and RMR = 22.09 Gm0.460 (R2 = 0.766). Beyond these correlations, the study delves into the intricate relationship between RMR and Rock Quality Designation (RQD) with Qslope values. The findings elucidate the following relationships: RMR = 34.05e0.33Qslope (R2 = 0.712) and RQD = 31.42e0.549Qslope (R2 = 0.902). Furthermore, leveraging the insights garnered from this comprehensive analysis, the study offers an empirically derived support system tailored to the distinct characteristics of discontinuous rock slopes, grounded firmly within the framework of the Qslope methodology. This holistic approach contributes significantly to advancing the understanding of sedimentary rock slope stability and provides valuable tools for informed engineering decisions.

Key Words
deformation modulus; geomechanical classification systems; Qslope; rock mass rating; rock quality designation; rock slope mass; sedimentary rock

Address
Yimin Mao: School of Information and Engineering, Shaoguan University, Shaoguan, Guangdong, China
Mohammad Azarafza and Masoud Hajialilue Bonab: Department of Civil Engineering, University of Tabriz, Tabriz, Iran
Marc Bascompta: Department of Mining Engineering, Polytechnic University of Catalonia, Spain
Yaser A. Nanehkaran: School of Information Engineering, Yancheng Teachers University, Yancheng, China

Abstract
In the current study, a series of experimental and analytical evaluations were performed to introduce the horizontal pseudo static coefficient (kh) as a function of the wall configuration and the reinforcement type for analyzing reinforced soil walls. For this purpose, eight shaking table tests were performed on reduced-scale models of integrated and two-tiered walls reinforced by metal strip and geogrid to determine the distribution of dynamic lateral pressure in the walls. Then, the physical models were analyzed using Mononobe-Okabe method to estimate the value of kh required to establish the dynamic lateral pressures similar to those observed in shaking table tests. Based on the results, the horizontal pseudo static coefficient and the position of resultant lateral force (R) were introduced as a function of the horizontal peak ground acceleration (HPGA), the wall configuration, the reinforcement type as well as maximum wall displacement.

Key Words
pseudo static coefficient; reinforced soil wall; shaking table test; tiered configuration

Address
Majid Yazdandoust: Department of Civil Engineering, University of Qom, Qom, Iran
Amirhossein Rasouli Jamnani: Department of Civil Engineering, University College of Rouzbahan, Sari, Iran
Mohsen Sabermahani: School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran

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