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model testing and Numerical Simulation of the Bearing Characteristics of Screw-Core Cement Mixing Pile

BUILDINGS 2025年第1期15卷 41-41页

作者： Wu, Luoan Gao, Yue Du, Yaohui Xuan, Junjie Nao, Jiu Li, Shibo Li, Jinhao Wang, Yanqi Zhang, Hao Cao, Lei Meng, Cheng Yang, Zewei Lanzhou Jiaotong Univ Dept Civil Engn Lanzhou 730070 Peoples R China Northwest Minzu Univ Dept Civil Engn Lanzhou 730100 Peoples R China Hubei Jianke Int Engn Co Ltd Wuhan 430010 Peoples R China

The screw-core mixing pile, which enhances traditional smooth-surface rigid piles by introducing a threaded surface, has been rapidly applied in China. Indoor model testing and numerical simulation techniques are used to perform static load tests on single piles to analyze the load-settlement relationship between the new screw-core mixing pile and the traditional circular-core mixing pile. The study examines the axial force distribution between the pile core and the mixing pile shell and establishes a bearing capacity model for screw-core mixing piles. Additionally, model piles with six different thread height ratios (w/d, where w is the thread width and d is the internal diameter of the screw-core) are developed using finite element simulation software to analyze the effect of thread height ratio on the bearing capacity of screw-core mixing piles. The influence of the height ratio on the bearing capacity of screw-core mixing piles is discussed in detail. The results indicate the following: (1) Due to differences in the pile core structure, the bearing capacity of the screw-core mixing pile is 1.44 times greater than that of the circular-core mixing pile. (2) When the vertical load is small, both the pile core and the mixing pile shell share the load;however, as the vertical load increases, the axial force gradually concentrates in the pile core, with the screw core showing a higher load-bearing capacity than the circular-core. (3) Under vertical load, the settlement of the screw-core mixing pile decreases stepwise from the top of the pile down to the surrounding area, demonstrating that the screw-core is more effective than the circular core. (4) The increase in thread height ratio significantly enhances the bearing capacity of the screw-core mixing pile. However, considering material limitations and engineering costs, the optimal thread height ratio should be determined based on actual bearing capacity requirements and soil conditions.

关键词： screw-core mixing pile pile-soil stress ratio model testing numerical simulation

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model testing on the Processes, Characteristics, and Mechanism of Water Inrush Induced by Karst Caves Ahead and Alongside a Tunnel

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ROCK MECHANICS AND ROCK ENGINEERING 2025年第5期58卷 5363-5380页

作者： Li, Zhi-Qiang Nie, Lichao Xue, Yiguo Li, Wei Fan, Kerui Shandong Univ Inst Geotech & Underground Engn Jinan 250061 Peoples R China Shandong Univ Sch Civil Engn Jinan 250061 Peoples R China China Univ Geosci Beijing Sch Engn & Technol Beijing 100083 Peoples R China China Univ Min & Technol State Key Lab Intelligent Construct & Hlth Operat Xuzhou 221116 Jiangsu Peoples R China Yunlong Lake Lab Deep Underground Sci & Engn Xuzhou 221008 Jiangsu Peoples R China Shandong Univ Sci & Technol Coll Civil Engn & Architecture Qingdao 266590 Peoples R China

The progressive failure process and stress-seepage pressure evolution of rock masses around tunnels are significant for preventing and controlling water inrush disasters. This study utilizes a self-developed three-dimensional fluid-solid coupling model test system to examine the impact of karst caves ahead and alongside a tunnel on the stability of the surrounding rock. It also analyzes the variations in stress and seepage pressure of rock masses during tunnel excavation. The model testing results indicate that excavation disturbance significantly impacts the stress-seepage pressure evolution of rock masses. The tunnel excavation's disturbance range is about 1.0-to-1.5 times the tunnel diameter. During tunnel-approaching karst caves, a negative correlation exists between stress and seepage pressure, with seepage pressure gradually decreasing while stress gradually increases. Furthermore, rock masses associated with karst caves at different locations exhibit different stress-seepage pressure evolution. During tunnel excavation approaching the karst cave alongside the tunnel, the seepage pressure gradient exhibits a funnel shape with the center at the midpoint of the karst cave, while the stress gradient shows an inverted funnel shape. After the tunnel moves away by a certain distance, both the seepage pressure and stress remain stable. During tunnel excavation approaching a karst cave ahead of the tunnel, a significant abrupt decrease in seepage pressure gradient indicates the imminent occurrence of a sudden water inrush. The changes in the stress field of the rock mass and the pore pressure inside fractures caused by construction disturbances are the main causes leading to the progressive failure of the rock mass, thereby triggering water inrush disasters. The observed characteristics of changes in seepage pressure and stress, as identified in this study, can provide a theoretical basis for the early warning and prevention of water inrush disasters.

关键词： model testing Water inrush Stress-seepage pressure evolution Karst cave Rock mass

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model testing of road tunnel ventilation in normal traffic conditions

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ENGINEERING STRUCTURES 2004年第12期26卷 1705-1711页

作者： Sambolek, M Brodarski Inst Zagreb 10020 Croatia

Ventilation testing on the model of the Sv. Rok tunnel is presented. The aim of the testing was to obtain the data necessary for the tunnel ventilation designing. These data are particularly important because longitudinal ventilation is planned, which is not often the case in such long tunnels with bidirectional traffic that will be in this tunnel until the completion of the second tunnel tube. The testing procedure is described, and the obtained experimental results and the ventilation system efficiency in normal traffic conditions are presented. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： road tunnel longitudinal ventilation model testing Sveti Rok tunnel normal traffic conditions

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model testing using data on ¹³⁷Cs from Chernobyl fallout in the Iput River catchment area of Russia

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JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2005年第2期84卷 225-244页

作者： Thiessen, KM Sazykina, TG Apostoaei, AI Balonov, MI Crawford, J Domel, R Fesenko, S Filistovic, V Galerlu, D Homma, T Kanyár, B Krajewski, P Kryshev, AI Kryshev, II Nedveckaite, T Ould-Dada, Z Sanzharova, NI Robinson, C Sjöblom, KL SENES Oak Ridge Inc Ctr Risk Anal Oak Ridge TN 37830 USA SPA Typhoon Inst Expt Meteorol Obninsk 249020 Russia IAEA A-1400 Vienna Austria Australian Nucl Sci & Technol Org Menai NSW 2234 Australia Russian Inst Agr Radiol & Agroecol Obninsk 249020 Russia Lithuania Acad Sci Inst Phys LT-02300 Vilnius Lithuania Inst Phys & Nucl Engn R-76900 Bucharest Romania Japan Atom Energy Res Inst Tokai Ibaraki 3191195 Japan Univ Veszprem H-8200 Veszprem Hungary Cent Lab Radiol Protect PL-03194 Warsaw Poland Dept Environm Food & Rural Affairs London SW1P 3JH England Radiat & Nucl Safety Author STUK FIN-00801 Helsinki Finland

Data collected for 10 years following the Chernobyl accident in 1986 have provided a unique opportunity to test the reliability of computer models for contamination of terrestrial and aquatic environments. The Iput River scenario was used by the Dose Reconstruction Working Group of the BIOMASS (Biosphere modelling and Assessment Methods) programme. The test area was one of the most highly contaminated areas in Russia following the accident, with an average contamination density of (137)CS of 800,000 Bq m(-2) and localized contamination up to 1,500,000 Bq m(-2), and a variety of countermeasures that were implemented in the test area had to be considered in the modelling exercise. Difficulties encountered during the exercise included averaging of data to account for uneven contamination of the test area, simulating the downward migration and changes in bioavailability Of (137)Cs in soil, and modelling the effectiveness of countermeasures. The accuracy of model predictions is dependent at least in part on the experience and judgment of the participant in interpretation of input information, selection of parameter values, and treatment of uncertainties. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： cesium-137 model testing dose reconstruction Chernobyl

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model testing of suction caissons in clay subjected to vertical loading

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APPLIED OCEAN RESEARCH 2010年第4期32卷 414-424页

作者： Villalobos, Felipe A. Byrne, Byron W. Houlsby, Guy T. Univ Oxford Dept Engn Sci Oxford OX1 3PJ England Univ Catolica Santisima Concepcion Fac Engn Concepcion Chile

A wide range of new offshore applications are emerging in the energy sector. The oil and gas industry is targeting minimum facility applications, whilst the renewable energy sector is developing offshore wind turbines, as well as a number of wave and tidal energy devices. The design and installation of the foundations are key considerations in the financial viability of such offshore engineering projects. Suction caisson foundations are a potential solution for these new developments, but design guidance is relatively sparse. This paper considers the vertical loading response of a caisson foundation in clay, during installation and under both monotonic and cyclic vertical loading. The main contribution is the presentation and interpretation of high quality experimental data. Vertical loading is critical for the design of a multi-footing structure of the type that might be used for large offshore wind turbines. We first consider the installation behaviour and compare data from pushed installations and a suction installation with results from a theoretical calculation. We then consider cyclic vertical loading tests, focussing on cyclic amplitudes that take the foundation into tension. Detailed displacement data and pore pressure data are presented. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Foundations Vertical loading Clay Cyclic loading Offshore engineering Suction caissons model testing Geotechnical engineering

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model testing using data on ¹³¹I released from Hanford

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JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2005年第2期84卷 211-224页

作者： Thiessen, KM Napier, BA Filistovic, V Homma, T Kanyár, B Krajewski, P Kryshev, AI Nedveckaite, T Nényei, A Sazykina, TG Tveten, U Sjöblom, KL Robinson, C SENES Oak Ridge Inc Ctr Risk Anal Oak Ridge TN 37830 USA Pacific NW Natl Lab Richland WA 99352 USA Lithuania Acad Sci Inst Phys LT-02300 Vilnius Lithuania Japan Atom Energy Res Inst Tokai Ibaraki 3191195 Japan Univ Veszprem H-8200 Veszprem Hungary Cent Lab Radiol Protect PL-03194 Warsaw Poland SPA Typhoon Inst Expt Meteorol Obninsk 249020 Russia Paks Nucl Power Plant Ltd H-7031 Paks Hungary Inst Energy Technol N-2027 Kjeller Norway Radiat & Nucl Safety Author FIN-00801 Helsinki Finland IAEA A-1400 Vienna Austria

The Hanford test scenario described an accidental release of I-131 to the environment from the Hanford Purex Chemical Separations Plant in September 1963. Based on monitoring data collected after the release, this scenario was used by the Dose Reconstruction Working Group of BIOMASS to test models typically used in dose reconstructions. The primary exposure pathway in terms of contribution to human doses was ingestion of contaminated milk and vegetables. Predicted mean doses to the thyroid of reference individuals from ingestion of I-131 ranged from 0.0001 to 0.8 mSv. For one location, predicted doses to the thyroids of two children with high milk consumption ranged from 0.006 to 2 mSv. The predicted deposition at any given location varied among participants by a factor of 5-80. The exercise provided an opportunity for comparison of assessment methods and conceptual approaches, testing model predictions against measurements, and identifying the most important contributors to uncertainty in the assessment result. Key factors affecting predictions included the approach to handling incomplete data, interpretation of input information, selection of parameter values, adjustment of models for site-specific conditions, and treatment of uncertainties. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： iodine-131 model testing dose reconstruction Hanford

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model testing OF SINGLE- AND THREE-STAGE MODIFIED SAVONIUS ROTORS AND VIABILITY STUDY OF MODIFIED SAVONIUS PUMP ROTOR SYSTEMS

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INTERNATIONAL JOURNAL OF GREEN ENERGY 2009年第1期6卷 22-41页

作者： Ghosh, P. Kamoji, M. A. Kedare, S. B. Prabhu, S. V. Indian Inst Technol Dept Mech Engn Bombay 400076 Maharashtra India Indian Inst Technol Dept Energy Sci & Engn Bombay 400076 Maharashtra India

The suitability of modified Savonius wind rotors for water-pumping application is studied with a mathematical model developed for estimating the discharge over a period of time. Single- and three-stage modified Savonius rotors, which are extensively tested in an open jet wind tunnel, are chosen. The best geometrical configuration for a single-stage rotor has shown a maximum coefficient of power of 19% at a Reynolds number of 120000, which increases with the increase in the Reynolds number. The coefficient of power at a higher Reynolds number experienced in the field trials is estimated by extrapolating the results at a lower Reynolds number. The discharge for these modified Savonius rotors is estimated from the mathematical models developed for roto-dynamic and piston pumps at design wind velocities of 6 and 8.5 m/sec. The estimated discharges for a single-stage rotor of 3 m diameter at design wind velocities of 6 and 8.5 m/sec are 5000 and 6000 m(3)/month for roto-dynamic pumps. The estimated discharge is substantially higher for roto-dynamic pumps than for piston pumps.

关键词： Modified Savonius rotors model testing Coefficient of power Reynolds number Rayleigh number Roto-dynamic pumps Piston pumps Discharge

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model testing the two-phase scavenging system in a two-stroke petrol engine

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING 2004年第D11期218卷 1307-1316页

作者： Cudina, M Univ Ljubljana Fac Mech Engn Ljubljana 1000 Slovenia

Due to an inadequate scavenging process two-stroke petrol engines suffer from substantial fuel-specific consumption, as well as from considerable emissions of toxic components in exhaust gases. This paper describes the model testing and evaluation of a new scavenging system in a small two-stroke petrol engine with internal working mixture preparation. The scavenging process is performed by two different gas media in two successive phases and is more sophisticated and effective than the conventional single-phase (Schnurle) principle. Using the similarity principle and dimensional analysis, a new mathematical model was developed for evaluation of the effectiveness of the scavenging systems. This makes it possible to establish relationships between the most important parameters of the model engine and of the real engine, which are independent of the dimensional parameters. The effectiveness of the scavenging systems was defined by means of qualitative scavenging efficiency. A special testing device for the model engine has been developed and a liquid working media (instead of gaseous) is used. A qualitative as well as a quantitative evaluation of the predicted values and a simulation of the working medium exchange process at different working conditions is possible. A visual observation of the slowed-down scavenging process in a transparent model cylinder was also made. The mathematical model can be applied to any scavenging system of two-stroke engines or to similar periodic events in the process technique.

关键词： two-stroke engine model testing two-phase scavenging system mathematical model process visualization

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model testing of flow phenomena in the squeeze chamber of a cold-chamber diecasting machine

Solid State Phenomena

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Solid State Phenomena 2011年 177卷 151-158页

作者： Stojek, Jerzy Dańko, Rafal Faculty of Mechanical Engineering and Robotics AGH Univesity of Science and Technology Cracow Poland Faculty of Foundry Engineering AGH Univesity of Science and Technology Cracow Poland

A review of the studies carried out on this subject so far was made, and the available mathematical models applicable at Phase I of the diecasing process were presented. Own model testing of the examined process phase was described. The tests were conducted on a laboratory station designed and constructed to serve this purpose. Basing on the obtained results, the fundamental Garber's model was modified and extended further to include the coefficient of liquid metal viscosity. © (2011) Trans Tech Publications, Switzerland.

关键词： Air Occlusion Die Casting model testing Statistical Analysis of Measurements Theory of Experiments

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model testing for Ship Hydroelasticity: A Review and Future Trends

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Journal of Shanghai Jiaotong university(Science) 2017年第6期22卷 641-650页

作者：焦甲龙任慧龙陈超核 School of Civil Engineering and Transportation South China University of Technology College of Shipbuilding Engineering Harbin Engineering University

Conducting model experiments is an effective and reliable way in the investigation of ship hydrodynamic and hydroelastic behaviors. A survey of model testing techniques for ship hydroelasticity and its prospect are presented in this paper. The research highlights with respect to ship hydroelasticity and key points in model testing are summarized at first. Then testing techniques including laboratory tank test and full-scale sea trial are reviewed, and both their advantages and disadvantages are analyzed comprehensively. Based on the conventional testing approaches, a state-of-the-art testing approach which includes performing tests using large-scale model at sea is proposed. Furthermore, recommendations towards the further development of ship hydroelasticity tests are forecasted and discussed.

关键词： ship hydroelasticity wave loads model testing sea trial large-scale model

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