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CONTENTS
Volume 30, Number 6, September25 2022
 

Abstract
In this study, a Gaussian process regression (GPR) model as well as six GPR-based metaheuristic optimization models, including GPR-PSO, GPR-GWO, GPR-MVO, GPR-MFO, GPR-SCA, and GPR-SSO, were developed to predict fly-rock distance in the blasting operation of open pit mines. These models included GPR-SCA, GPR-SSO, GPR-MVO, and GPR. In the models that were obtained from the Soungun copper mine in Iran, a total of 300 datasets were used. These datasets included six input parameters and one output parameter (fly-rock). In order to conduct the assessment of the prediction outcomes, many statistical evaluation indices were used. In the end, it was determined that the performance prediction of the ML models to predict the fly-rock from high to low is GPR-PSO, GPR-GWO, GPR-MVO, GPR-MFO, GPR-SCA, GPR-SSO, and GPR with ranking scores of 66, 60, 54, 46, 43, 38, and 30 (for 5-fold method), respectively. These scores correspond in conclusion, the GPR-PSO model generated the most accurate findings, hence it was suggested that this model be used to forecast the fly-rock. In addition, the mutual information test, also known as MIT, was used in order to investigate the influence that each input parameter had on the fly-rock. In the end, it was determined that the stemming (T) parameter was the most effective of all the parameters on the fly-rock.

Key Words
fly-rock; hybrid models; machine learning; metaheuristic optimization; sensitivity analysis

Address
Arsalan Mahmoodzadeh: Rock Mechanics Division, School of Engineering, Tarbiat Modares University, Tehran, Iran
Hamid Reza Nejati: Rock Mechanics Division, School of Engineering, Tarbiat Modares University, Tehran, Iran
Mokhtar Mohammadi: Department of Information Technology, College of Engineering and Computer Science, Lebanese French University, Kurdistan Region, Iraq
Hawkar Hashim Ibrahim: Department of Civil Engineering, College of Engineering, Salahaddin University-Erbil, 44002 Erbil, Kurdistan Region, Iraq
Shima Rashidi: Department of Computer Science, College of Science and Technology, University of Human Development,
Sulaymaniyah, Kurdistan Region, Iraq
Adil Hussein Mohammed: Department of Communication and Computer Engineering, Faculty of Engineering, Cihan University-Erbil, Kurdistan Region, Iraq

Abstract
The permeability coefficient is an essential parameter for the study of seepage flow in fractured rock mass. This paper discusses the feasibility and application value of using readily available RQD (rock quality index) data to estimate mine water inflow and grouting quantity. Firstly, the influence of different fracture frequencies on permeability in a unit area was explored by combining numerical simulation and experiment, and the relationship between fracture frequencies and pressure and flow velocity at the monitoring point in fractured rock mass was obtained. Then, the stochastic function generation program was used to establish the flow analysis model in fractured rock mass to explore the relationship between flow velocity, pressure and analyze the universal law between fracture frequency and permeability. The concepts of fracture width and connectivity are introduced to modify the permeability calculation formula and grouting formula. Finally, based on the on-site grouting water control example, the rock mass quality index is used to estimate the mine water inflow and the grouting quantity. The results show that it is feasible to estimate the fracture frequency and then calculate the permeability coefficient by RQD. The relationship between fracture frequency and RQD is in accordance with exponential function, and the relationship between structure surface frequency and permeability is also in accordance with exponential function. The calculation results are in good agreement with the field monitoring results, which verifies the rationality of the calculation method. The relationship between the rock mass RQD index and the rock mass permeability established in this paper can be used to invert the mechanical parameters of the rock mass or to judge the permeability and safety of the rock mass by using the mechanical parameters of the rock mass, which is of great significance to the prediction of mine water inflow and the safety evaluation of water inrush disaster management.

Key Words
fracture frequency, grouting estimation, permeability, RQD, water inflow

Address
Jinhai Zhao, Qi Liu:State Key Laboratory Breeding Base for Mining Disaster Prevention and Control, Shandong University of Science and Technology, Qingdao 266590, China; College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China
Changbao Jiang: State Key Laboratory Breeding Base for Mining Disaster Prevention and Control, Shandong University of Science and Technology, Qingdao 266590, China; College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, School of Resources and Safety Engineering, Chongqing University, Chongqing 400030, China
Wang Defeng: Institute of Mining and Special Civil Engineering, Technical University of Bergakademie Freiberg, Freiberg, 09599 Dresden, Germany

Abstract
Every year, millions of waste tires are discarded across the world. Storage of waste tires presents many problems such as fire threats, epidemics, and non-economic factors. Furthermore, the disintegration process of waste tires is not economical or practical due to its time-consuming, and disposal requirements. In this study, half-section waste tires (HSWTs) were integrated with high-density polyethylene (HDPE) pipes under different relative density conditions. The main aim of the study was to reduce the deformation values of embedded HDPE pipes in sandy soil and to evaluate the soil–pipe interaction. In comprehensive laboratory tests, half-section waste tires were integrated in two different ways: in the middle of the pipeline and along the pipeline. Accordingly, it was concluded that the effectiveness of waste tires reduces the deformation and bending moment values in the critical regions of pipes. As a result of reinforcement in the mid-point of the pipe defined as the most critical region, 52% and 36% less deformation was observed in the crown and springlines of the pipe, respectively. In addition, the bending moment values for the same critical section were determined to be 40% less in the crown and 28% less in the springline regions of the pipe.

Key Words
deformation behavior, HDPE pipe, reinforcement, silica sand, waste tire

Address
Can Erenson and Niyazi Uğur Terzi: Department of Civil Engineering, Aksaray University, Geotechnical Division, Aksaray, Türkiye

Abstract
This paper presents a more general model for T-shaped combined footings that support two columns aligned on a longitudinal axis and each column provides an axial load and two orthogonal moments. This model can be applied to the following conditions: (1) without restrictions on its sides, (2) a restricted side and (3) two opposite sides restricted. This model considers the linear soil pressure. The recently published works have been developed for a restricted side and for two opposite sides restricted by Luévanos-Rojas et al. (2018a, b). The current model considers the uniform pressure distribution because the position of the resultant force coincides with the center of gravity of the surface of the footing in contact with the soil in direction of the longitudinal axis where the columns are located. This paper shows three numerical examples. Example 1 is for a T-shaped combined footing with a limited side (one column is located on the property boundary). Example 2 is for a T-shaped combined footing with two limited opposite sides (the two columns are located on the property boundary). Example 3 is for a T-shaped combined footing with two limited opposite sides, one column is located in the center of the width of the upper flange (b1/2=L1), and other column is located at a distance half the width of the strip from the free end of the footing (b2/2=b–L1–L). The main advantage of this work over other works is that this model can be applied to T-shaped combined footings without restrictions on its sides, a restricted side and two opposite sides restricted. It also shows the deficiencies of the current model over the new model.

Key Words
bending moments; bending shear; combined footings; punching shear; reinforced concrete

Address
Jesús Rafael Garay-Gallegos, Arnulfo Luévanos-Rojas, Sandra López-Chavarría, Manuel Medina-Elizondo, Gabriel Aguilera-Mancilla and Edith García-Canales: Institute of Multidisciplinary Researches, Autonomous University of Coahuila, Blvd. Revolución No, 151 Ote, CP 27000, Torreón, Coahuila, México

Abstract
Accidental anchor drop can cause disturbances to seabed materials and pose significant threats to the safety and serviceability of submarine structures such as pipelines. In this study, a series of anchor drop tests was carried out to investigate the penetration mechanism of a Hall anchor in sand and clay. A special anchor drop apparatus was designed to model the inflight drop of a Hall anchor. Results indicate that Coriolis acceleration was the primary cause of large horizontal offsets in sand, and earth gravity had negligible impact on the lateral movement of dropped anchors. The indued final horizontal offset was shown to increase with the elevated drop height of an anchor, and the existence of water can slow down the landing velocity of an anchor. It is also observed that water conditions had a significant effect on the influence zone caused by anchors. The vertical influence depth was over 5 m, and the influence radius was more than 3 m if the anchor had a drop height of 25 m in dry sand. In comparison, the vertical influence depth and radius reduced to less than 3 m and 2 m, respectively, when the anchor was released from 10 m height and fell into the seabed with a water depth of 15 m. It is also found that the dynamically penetrating anchors could significantly influence the earth pressure in clay. There is a non-linear increase in the measured penetration depth with kinematic energy, and the resulted maximum earth pressure increased dramatically with an increase in kinematic energy. Results from centrifuge model tests in this study provide useful insights into the penetration mechanism of a dropped anchor, which provides valuable data for design and planning of future submarine structures.

Key Words
anchor drop test; centrifuge modeling; earth pressure; kinematic energy; penetration mechanism

Address
Xiaoyu An: State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China; National Engineering Laboratory for Port Hydraulic Construction Technology, Tianjin Research Institute for Water Transport Engineering, M.O.T., Tianjin 300456, China
Fei Wang: National Engineering Laboratory for Port Hydraulic Construction Technology, Tianjin Research Institute for Water Transport Engineering, M.O.T., Tianjin 300456, China
Chao Liang and Run Liu: State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China

Abstract
Fragmenting the rock mass is considered as the most important work in open-pit mines. Ground vibration is the most hazardous issue of blasting which can cause critical damage to the surrounding structures. This paper focuses on developing an explicit model to predict the ground vibration through an multi objective evolutionary polynomial regression (MOGA-EPR). To this end, a database including 79 sets of data related to a quarry site in Malaysia were used. In addition, a gene expression programming (GEP) model and several empirical equations were employed to predict ground vibration, and their performances were then compared with the MOGA-EPR model using the mean absolute error (MAE), root mean square error (RMSE), mean (u), standard deviation of the mean (r), coefficient of determination (R2) and a20-index. Comparing the results, it was found that the MOGA-EPR model predicted the ground vibration more precisely than the GEP model and the empirical equations, where the MOGA-EPR scored lower MAE and RMSE, u and r closer to the optimum value, and higher R2 and a20-index. Accordingly, the proposed MOGA-EPR model can be introduced as a useful method to predict ground vibration and has the capacity to be generalized to predict other blasting effects.

Key Words
blasting, ground vibration, multi objective genetic algorithm evolutionary polynomial regression, prediction models

Address
Saif Alzabeebee; Department of Roads and Transport Engineering, University of Al-Qadisiyah, Iraq
Mehdi Jamei: Engineering Faculty, Shohadaye Hoveizeh Campus of Technology, Shahid Chamran University of Ahvaz, Dashte Azadegan, Khuzestan, Iran
Mahdi Hasanipanah: Department of Mining Engineering, University of Kashan, Kashan, Iran
Hassan Bakhshandeh Amnieh: School of Mining, College of Engineering, University of Tehran, Tehran 11155-4563, Iran
Masoud Karbasi: Water Engineering Department, Faculty of Agriculture, University of Zanjan, Zanjan, Iran
Suraparb Keawsawasvong: Department of Civil Engineering, Thammasat School of Engineering, Thammasat University, Pathumthani, 12120, Thailand

Abstract
In this study, a series of three-dimensional numerical parametric study was conducted to investigate deformation mechanisms of an existing box culvert due to an adjacent multi-propped basement excavation in clays. Field measurements from an excavation case history are first used to calibrate a baseline Hardening Soil Small Strain (HS-small) model, which is subsequently adopted for parametric study. Results indicate that the basement-box culvert interaction along the basement centerline can be considered as a plane strain condition when the length of excavation (L) reaches 14 He (i.e., final excavation depth). If a plane strain condition (i.e., L/He=12.0) is assumed for analyzing the basement-box culvert interaction of a short excavation (i.e., L/He=2.0), the maximum settlement and horizontal movement of the box culvert are overestimated significantly by up to 15.7 and 5.1 times, respectively. It is also found that the deformation of box culvert can be greatly affected by the basement excavation if the distance between the box culvert and retaining wall is less than 1.5 He. The induced deformation in the box culvert can be dramatically reduced by improving the ground inside the excavation or implementing other precautionary measures. For example, by adding jet grouting columns within the basement and installing an isolation wall behind the retaining structures, the maximum settlements of box culvert are shown to reduce by 37.2% and 13.4%, respectively.

Key Words
basement excavation; box culvert; horizontal movement; settlement; three-dimensional

Address
Fanmin Bu, Wenrui Yu: CCCC Fourth Highway (Beijing) Highway Test Checking Technology Co., Ltd, Beijing 101107, China
Li Chen: Nanjing Gongda Construction Technology Co., Ltd, Nanjing, Jiangsu 210009, China
Erlu Wu: Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210024, China

Abstract
Pile-supported structures are installed on saturated sloping grounds, where the ground stiffness may decrease due to liquefaction during earthquakes. Thus, it is important to consider saturated sloping ground and pile interactions. In this study, we conduct a centrifuge test of a pile-supported structure, and analyze the p-yp loops, p-yp loops provide the correlation between the lateral pile deflection (yp) and lateral soil resistance (p). In the dry sand model (UV67), the p-yp loops stiffness increased as ground depth increased, and the p-yp loops stiffness was larger by approximately three times when the pile moved to the upslope direction, compared with when it moved to the downslope direction. In contrast, no significant difference was observed in the stiffness with the ground depth and pile moving direction in the saturated sand model (SV69). Furthermore, we identify the unstable zone based on the result of the lateral soil resistance (p). In the case of the SV69 model, the maximum depth of the unstable zone is five times larger than that of the dry sand model, and it was found that the saturated sand model was affected significantly by kinematic forces due to slope failure.

Key Words
centrifuge model test, dynamic p-yp loops, liquefaction, pile-supported structure, unstable zone, unstable zone

Address
Jungwon Yun: Department of Civil Engineering, Korea Army Academy at Yeongcheon, Yeongcheon, Korea
Jintae Han: Department of Geotechnical Engineering Research, Korea Institute of Civil Engineering and Building Technology, Gyeonggi, Korea
Doyoon Kim: Department of Civil Engineering, Korea Army Academy at Yeongcheon, Yeongcheon, Korea

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