Abstract
Predicting the fracture toughness of rocks, particularly under Mode-I loading conditions, is essential for various geotechnical and civil engineering applications. Traditional methods for determining rock fracture toughness (RFT) are often labor-intensive, time-consuming, and prone to inaccuracies due to the inherent variability in rock properties. This study investigates the efficacy of using a stacking regressor, an advanced ensemble learning technique, to predict the Mode-I RFT. In the proposed model, the strengths of multiple base regressors were combined. 400 experimental data points were utilized, obtained using the cracked Chevron notched Brazilian disc (CCNBD) test and comprising six input parameters affecting the Mode-I RFT. The dataset was partitioned into training and validation sets, ensuring rigorous model evaluation. The stacking regressor's meta-model was trained on the outputs of the base models, effectively learning to integrate their predictions to yield a more accurate final prediction. The performance of the stacking regressor was assessed through several statistical metrics. The results demonstrated that the stacking regressor significantly outperforms individual base models, achieving higher predictive accuracy and reliability. A sensitivity analysis using the mutual information test (MIT) method revealed that the uniaxial tensile strength (UCS) exerts the most significant influence on the Mode-I RFT, underscoring its importance in predictive modeling. Furthermore, developing a machine learning-based graphical user interface (GUI) enhanced the practical applicability of the proposed model, making it accessible to engineers and researchers without extensive expertise in machine learning.
Address
Ibrahim Albaijan and Hussein Alrobei: Mechanical Engineering Department, College of Engineering at Al-Kharj, Prince Sattam Bin Abdulaziz University,
Al Kharj 16273, Saudi Arabia
Arsalan Mahmoodzadeh: Center of Research and Strategic Studies, Lebanese French University, Erbil, Iraq
Mokhtar Mohammadi: Department of Information Technology, College of Engineering and Computer Science,
Lebanese French University, Kurdistan Region, Iraq
Abstract
This study aims to accurately identify periods of ground and lengthened period of multi-degree-of-freedom structures installed on shallow foundations in dynamic centrifuge model tests using the frequency domain decomposition (FDD) method. A series of dynamic centrifuge model tests were conducted with single- and multi-degree-of-freedom structures installed on shallow foundations and sandy ground. The frequency domain decomposition method was utilized to identify the ground period and the lengthened structure period. The results obtained from the FDD method for the soil–structure system, including periods and mode shapes, are compared with those calculated using conventional methods such as response spectrum (RS), ratio of response spectrum (RRS), fast Fourier transforms (FFT), and ratio of fast Fourier transforms (RFFT). The comparison demonstrates that FDD is effective in terms of both simplicity and accuracy for the modal analysis of complex soil–structure systems based on centrifuge test data.
Key Words
centrifuge modelling; frequency domain decomposition; lengthened structure period; multi-degree-freedom structure; natural period of ground; shallow foundations; soil-structure interaction
Address
Seong Jin Park, Dong Van Nguyen, Dookie Kim and Yun Wook Choo: Department of Civil and Environmental Engineering, Kongju National University (31080)
1223-24, Cheonan-daero, Seobuk-gu, Cheonan-si, Chungcheongnam-do (275 Budae-dong), Republic of Korea
Abstract
In order to solve the collapse failure problem of overlying rock mass in shallow tunnels during earthquake, and to guide the design of tunnels safety width and the reinforcement of overlying rock mass, the prediction method of collapse failure curve under earthquake is studied. The main means is to simulate the seismic wave action on the overlying rock mass by the pseudo-dynamic method, establish the virtual power equation in the upper bound theorem based on the Hoek-Brown criterion, and solve it by the variational method of the variable endpoint problem. The effects of seismic wave parameters, rock mass strength parameters and engineering parameters on the predicted collapse area are analysed. The results show that the horizontal seismic acceleration affects the shape of the collapsing rock block, while the vertical seismic acceleration affects the size; the rock mass with weak strength and high density has a small size of collapsed rock block. By referring to the influence of engineering parameters, reducing the depth of the tunnel and uniform load on the surface and increasing the supporting pressure on the overlying rock mass can help to restrain the occurrence of collapse.
Address
Jiayun Liang: School of Civil Engineering, Guangzhou University, Guangzhou, 510006, China;
Guangzhou Pearl River Construction Development CO. LTD., Guangzhou, Guangdong, 510075, China
Jie Cui,Yadong Li and Yi Shan: School of Civil Engineering, Guangzhou University, Guangzhou, 510006, China;
Guangdong Provincial Engineering and Technology Research Center of Geo-Structure Safety and Protection, Guangzhou University, Guangzhou, Guangdong, 510006, China
Zhicheng Yang: College of Urban and Rural Construction, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
Marco Donà: Guangzhou Pearl River Construction Development CO. LTD., Guangzhou, Guangdong, 510075, China;
Department of Geosciences, University of Padova, Via G. Gradenigo 6, 35131 Padua, Italy
Abstract
The use of biopolymer hydrogels for bioinspired piles is emerging as a sustainable approach to enhance penetration efficiency and ensure pile stability after installation. Xanthan gum (XG) hydrogels possess shear-thinning properties, which reduce penetration resistance under high shear strain conditions. However, their limited durability under wet conditions restricts their field application. To address this, this study introduces trivalent chromium (Cr3+) crosslinked XG and investigates the mechanical performance enhancement of treated soils and piles. Rheological tests revealed that both XG and Cr–XG hydrogels exhibited shear-thinning behavior with increasing shear rate, whereas Cr3+ crosslinking significantly increased yield stress and flow point, thereby enhancing structural stability after gelation. Direct and interface shear-test results showed that XG concentration and Cr3+ addition significantly increased cohesion and interface adhesion. Laboratory-scale pile-penetration tests demonstrated that XG-hydrogel injection reduced end bearing and skin friction during penetration, improving installation efficiency. The pile treated with 1.0% Cr–XG exhibited the highest pullout resistance post-installation. These results demonstrate the potential of the Cr–XG 1.0% hydrogel to simultaneously improve penetration efficiency and post-installation stability, presenting a bioinspired strategy for sustainable pile-foundation design.
Address
Suhyuk Park, Saebom Kim and Ilhan Chang: Department of Civil Systems Engineering, Ajou University, Suwon 16499, Republic of Korea
Su-Choel Kim: Civil Engineering Headquarters, Kumho E&C, Seoul 03161, Republic of Korea
Abstract
This study proposes a methodology for predicting the extent of transportation loss in a newly developed railway network during seismic events. In this process, a direct estimation method for the OD (Origin-Destination) matrix was employed to derive the population movement ratio for each railway line, which was then used to estimate the approximate volume of transported population across the railway network. The transportation volume was estimated using the actual boarding and alighting data from a railway line in Seoul and a destination-based OD Matrix model. Next, the functionality loss of each structural component in the railway network was derived by integrating seismic fragility curves with restoration curves. The functionality loss of individual railway infrastructure components was evaluated for earthquake magnitudes ML=6 and ML=7, using the Korean ground motion attenuation equation, epicentral distance, and short-period amplification factors. Subsequently, the overall average functionality loss of the railway network was calculated by incorporating the functionality loss and length of each railway line. For a more conservative assessment, the maximum functionality loss within each segment was also considered. As a result, for an earthquake with magnitude ML=6, the transportation loss of the simulated railway network was estimated to be 7.65% when reflecting the average functionality loss, and 15.13% when reflecting the maximum functionality loss. Subsequently, under an ML=7 earthquake scenario, the transportation loss for the simulated railway network was predicted to be 19.37% when reflecting average functionality loss and 30.14% when reflecting maximum functionality loss.
Key Words
earthquake; fragility curve; functionality loss; OD Matrix; transportation volume loss
Address
Jiyun Jeon and Mintaek Yoo: Department of Civil and Environmental Engineering, Gachon University, South Korea
Ji Hyeon Kim: Advanced Railroad Civil Engineering Division, Korea Railroad Research Institute, South Korea
Abstract
The importance of the kinematic effects, especially at the interface in the layered ground, on the behavior of seismically loaded piles, has been recognized well by academia and industry. In this paper, several widely utilized simplified models for estimating the maximum kinematic pile bending at the interfaces in the layered ground are reviewed, and a series of three-dimensional (3D) numerical models for piles with various spacings, pile numbers, ground conditions, and pile dimensions are employed to examine the kinematic interactions between soil and pile foundations. Based on the extensive numerical parametric study, the group reduction effects for kinematic bending moment are discussed, and the feasibility and reliability of the reviewed simplified models under different ground conditions are evaluated sufficiently. Finally, several empirical formulas for estimating the maximum kinematic pile bending moment under different ground conditions are proposed in this study. Notably, this study presents the first attempt to validate and modify these simplified models specifically for triple-layered ground through comprehensive 3D numerical parametric analysis. Compared with existing models that are mainly applicable to uniform or double-layered ground, the empirical formulas proposed in this study demonstrate applicability for both double-layered and triple-layered ground conditions, significantly enhancing the prediction accuracy of kinematic bending moments of piles under seismic loading in complex ground systems.
Address
Ruping Luo and Bitang Zhu: State Key Laboratory of Safety and Resilience of Civil Engineering in Mountain Area, East China Jiaotong University,
Nanchang, 330013, P.R. China;
School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, P.R. China;
Engineering Research & Development Centre for Underground Technology of Jiangxi Province; East China Jiaotong University,
Nanchang 330013, P.R. China
Jie Li and Xuehui Jiang: School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, P.R. China
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