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Investigation of mechanical properties and elucidation of factors affecting wood-based structural panels under embedment stress with a circular dowel i: analysis of the influence of various conditions on the embedment properties

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JOURNAL OF WOOD SCIENCE 2023年第1期69卷 1-15页

作者： Sudo, Ryutaro Aoki, Kenji Inayama, Masahiro Univ Tokyo Grad Sch Agr & Life Sci Dept Biomat Sci 1-1-1 YayoiBunkyo Ku Tokyo Japan Forestry & Forest Prod Res Inst 1 Matsunosato Tsukuba Ibaraki 3058687 Japan

embedment properties are vital to timber structural designs, and many types of wood-based structural panels have been developed for diverse uses. Comprehensive and systematic studies regarding the embedment properties of wood-based structural panels are limited. In this study, a jig that allows the observation of fracture processes is developed, and a monotonic tensile embedment test is conducted on plywood, oriented strandboard (both strong and weak axes), particleboard, medium density fiberboard, and hardboard. The parameters used in the test are the dowel diameter, pilot hole size, and end and edge distances. The effects of these parameters on the embedment properties (i.e., the failure mode, ductility, maximum stress, and yield stress) are discussed comprehensively. The failure mode is determined by the edge distance. At a sufficient edge distance, ductile failure occurs, and the load is maintained until the remaining end distance reaches a certain value. The maximum stress and yield stress are analyzed quantitatively via standardized multiple regression analysis. The results suggest the following: (i) The ratio of the in-plane strength to the internal bond strength is related to the failure behavior;(ii) the dowel diameter, fiber direction, and load levels affect the stress spread pattern of the embedment pressure.

关键词： Wood-based structural panel Plywood (PW) Oriented strand board (OSB) Particleboard (PB) Medium density fiberboard (MDF) Hardboard (HB) Bearing embedment Pilot hole Edge distance End distance Standardized multiple regression analysis (SMRA)

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A Simplified Analytical Elastoplastic embedment Depth Model of Proppant Based on the Drucker-Prager Yield Criterion

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ROCK MECHANICS AND ROCK ENGINEERING 2023年第9期56卷 6207-6217页

作者： He, Bo Xie, Lingzhi Che, Yongxin Zhang, Yao Liu, Jun Sichuan Univ Inst New Energy & Low Carbon Technol Chengdu 610207 Peoples R China Sichuan Univ Engn Res Ctr Alternat Energy Mat & Devices Minist Educ Chengdu 610065 Peoples R China Sichuan Univ Coll Architecture & Environm Chengdu 610065 Peoples R China

In deep shale gas reservoir exploration, elastoplastic embedment plays an increasingly important role in analyses of the conductivity of fracture networks because it is affected by high temperature, high in-situ stress. To obtain a full understanding of proppant embedding behavior, an analytical model of the embedment depth of a single spherical proppant was developed based on the Drucker-Prager (D-P) yield criterion and shale elastoplastic mechanical behavior. Shale indentation tests with rigid balls with diameters of 0.8 mm and 1.0 mm were conducted to validate the reliability of the theoretical model. Compared with the Hertz, Thornton and non-linear models, the new model developed in this paper was in better agreement with embedment experimental data. Each parameter of the new model has clear physical meaning and can be obtained by a series of triaxial compression tests. An Analysis of Variance (ANOVA) method was applied to discuss the sensitivity of the model to the parameters, and the results showed that the strength parameters alpha and Y contributed the most to, and had nonlinear effects on, the proppant embedment depth.

关键词： embedment Proppant Nonlinear Shale Elastic-plastic

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Behavior of Piggy-Backed Drag embedment Anchors in Marine Soils

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JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING 2022年第1期148卷 04021167-04021167页

作者： Lai, Ying Huang, Yunhan Gilbert, Robert B. Aubeny, Charles P. Zhejiang Univ Coll Civil Engn & Architecture 866 Yuhangtang Rd Hangzhou 310058 Zhejiang Peoples R China Jiangsu Ocean Univ Coll Civil & Harbor Engn Lianyungang 222005 Jiangsu Peoples R China Univ Texas Austin Dept Civil Architectural & Environm Engn Austin TX 78712 USA Texas A&M Univ Zachry Dept Civil Engn 201 Dwight Look Engn Bldg College Stn TX 77843 USA

This paper summarizes the analytical and experimental results of piggy-backed drag embedment anchors composed of two drag embedment anchors. Drag embedment tests with piggy-backed drag embedment anchors were performed with the spacing between the two anchors at 5.4 fluke length. The experimental results provide a validation of analytical model. The study reveals that: (1) the calibrated piggy-backed prediction model can predict the capacity, trajectory, and pitch of the front and back anchor in the piggy-backed configuration, and (2) the total capacity of the piggy-backed drag embedment anchors can be greater than twice the capacity of an individual anchor because the piggy-back arrangement forces the front anchor to mobilize more rotational resistance than when it is free to rotate as an individual anchor.

关键词： Marine soil Piggy-backed drag embedment anchors Capacity embedment Trajectory

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Effect of embedment Depth on Cyclic Behavior of Tank Footings on Dry Sand

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TRANSPORTATION INFRASTRUCTURE GEOTECHNOLOGY 2022年第2期9卷 220-235页

作者： Fattah, Mohammed Y. Karim, Hussein H. Al-Qazzaz, Hiba H. Univ Technol Baghdad Civil Engn Dept Baghdad Iraq

Fuel tank footings are usually subjected to cyclic loads caused by filling and emptying of these tanks. In addition, in a multitude of geotechnical applications, soils are subjected to cyclic loading. Besides vehicle and traffic loads, cyclic loads also play an important role in pile driving processes and during the dimensioning of foundations for offshore wind craft plants. Research on the cyclic vertical loading problem for sand is particularly scarce, and most has been in commercial confidence. This paper is conducted to study the experimental behavior of dry sandy soil under foundations subjected to vertical cyclic compression load. A total of sixty-three models have been tested to study the behavior of shallow footings under cyclic load of different rates. A new compression machine was manufactured to apply both monotonic and cyclic loading. Three relative densities of sand, two footing shapes, three depths of foundation embedment, and three rates of loading were tried. It was concluded that with more depth of the footing (D-f increasing), the soil settlement decreases. In general, when other factors are remaining constant, the bearing capacity of the soil goes on increasing when the depth or width of the foundation increases. The total settlement of a footing continues to increase during the time of the load and reaches a maximum value at the end of dwell time. During the decay period of the load, the footing rebounds to some degree.

关键词： Footing embedment Cyclic load Tank Sand

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Reform of China's taxation system: from embedment in the economy to embedment in society

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JOURNAL OF CHINESE SOCIOLOGY 2022年第1期9卷 1-23页

作者： Lv, Bingyang Zhang, Zhaoqiang Renmin Univ China Sch Finance Beijing Peoples R China Capital Univ Econ & Business Sch Publ Finance & Taxat Beijing Peoples R China

To match national development goals and increase in the tax base, the government must embed a taxation system in economic and social contexts. Since the founding of the People's Republic of China, the development of taxation can be divided into three stages: one that is embedded in danwei, one that is embedded in enterprises, and one that is embedded in society. The corresponding national development goals include stimulating economic growth, promoting coordinated economic and social development, and propelling state governance. As the tax base in China shifts from production to redistribution and wealth accumulation in the circulation of the national income, the taxation system will gradually shift from embedment in the economy to embedment in society, posing new challenges to taxation system reform. Future reform should deepen the extent to which taxation is embedded in society while keeping taxation embedded in a broad economic base. This will help to achieve the goal of building a "consensually strong state."

关键词： Taxation system National development Tax base embedment

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The impact of embedment of the side arms of 52 mg levonorgestrel-intrauterine device on bleeding and pain: A prospective cohort study

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JOURNAL OF GYNECOLOGY OBSTETRICS AND HUMAN REPRODUCTION 2024年第6期53卷 102777-102777页

作者： Heijden, P. A. H. H. van der Bongers, M. Y. Veersema, S. Dieleman, J. P. Geomini, P. M. A. J. Anna Hosp Geldrop Dept Obstet & Gynaecol Bogardeind 2 NL-5664 EH Geldrop Netherlands Maxima Med Ctr Veldhoven Dept Obstet & Gynaecol de Run 4600 NL-5504 DB Veldhoven Netherlands Maastricht Univ Med Ctr Maastricht Res Sch Oncol & Reprod Grow P Debyelaan 25 NL-6229 HX Maastricht Netherlands Univ Med Ctr Utrecht Dept Reprod Med & Gynecol Heidelberglaan 100 NL-3584 CX Utrecht Netherlands Maxima Med Ctr Veldhoven Dept Sci de Run 4600 NL-5504 DB Veldhoven Netherlands

Purpose: The purpose of this study was to analyse the impact of embedment of side arms of the levonorgestrel 52 mg intrauterine device (LNG-IUD) in the myometrium (assessed by three-dimensional transvaginal ultrasound (3D-TVUS)) on uterine bleeding and pain. Materials and methods: We performed a prospective cohort study in a large Dutch teaching hospital between February 2015 and December 2016. Participants over 18 years of age who selected a LNG-IUD for contraception or because of heavy menstrual bleeding were eligible for inclusion. Six weeks after insertion, a 3D-TVUS was performed to diagnose embedment of the side arms. At that moment participants filled in questionnaires about their bleeding pattern and pelvic pain. Menstruation patterns 'no bleeding', 'regular menstruation', 'sometimes a day of spotting (maximum once a week)' were classified as favourable bleeding pattern. Menstruation patterns 'heavy menstrual bleeding', 'several days a week bleeding days', 'several days a week spotting days', 'continuously spotting', and 'completely irregular cycle' were classified as unfavourable bleeding pattern. Univariate and multivariate logistic regression analysis was used to calculate odds ratios (OR) and 95 %-confidence intervals (CI). The multivariate analysis included endometrial thickness, reason for insertion and parity. The analysis of pelvic pain additionally included previous insertion. Results: A total of 220 participants were evaluated for the study of whom 176 returned the questionnaires. embedment of the side arms was observed in 43 of the 176 responding participants (24.4 %). Favourable bleeding pattern was reported by 25/43 (58.1 %) participants with embedment and 53/133 (39.8 %) participants without embedment (ORadj 1.8, 95 % CI 0.9-3.9). Pelvic pain was reported by 4/43 (9.3 %) participants with embedment and 24/133 (18.1 %) participants without embedment (ORadj 0.3;CI 0.1-1.2). Conclusions: The present study suggests that embedment of the side arms o

关键词： Levonorgestrel intrauterine device embedment Pain Bleeding Three-dimensional ultrasound Short condensation

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Correction charts for soil layering and embedment of a vertically vibrating footing

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INTERNATIONAL JOURNAL OF GEOTECHNICAL ENGINEERING 2021年第2期15卷 151-159页

作者： Sutaih, G. Aggour, M. S. King Abdulaziz Univ Dept Civil & Environm Engn Jeddah Saudi Arabia Univ Maryland Dept Civil & Environm Engn College Pk MD 20742 USA

A finite element solution was used to analyse a vertically vibrating footing supported on two-layered soils as well as a footing with a different depth of embedment. Variables considered were the thickness of the top layer, properties of each layer and the depth of embedment. Correction charts were then developed in comparison to a footing on the ground surface and supported by a homogeneous soil layer. The charts can provide an understanding of the effect of different parameters affecting the footing vibration behaviour and will be useful in the preliminary stage of the footing design process.

关键词： Vertical vibration of footing soil layering embedment spring constant damping ratio finite element method

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Modeling Fracture Closure with Proppant Settling and embedment during Shut-In and Production

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SPE DRILLING & COMPLETION 2020年第4期35卷 668-683页

作者： Zheng, Shuang Manchanda, Ripudaman Sharma, Mukul M. Univ Texas Austin Austin TX 78712 USA

Fracture closure and proppant settling are two fully coupled processes during both shut-in and production. Proppant distribution greatly affects the residual fracture width and conductivity evolution, whereas fracture closure might limit proppant settling and force the proppant to crush or embed into the rock. Modeling fracture closure with proppant settling and embedment is challenging because of the multiple coupled physical processes involved, large time-scale differences, and extreme nonlinearity in the coupling of the processes. Conventional fracture-closure models either use simplified analytical estimates of the stress-dependent permeability of the reservoir or explicitly calculate the fracture width using empirical relationships, without considering the effect of fluid leakoff and dynamic changes in the proppant distribution in the fracture. In this work, we use a novel fully implicitly coupled fracturing/reservoir simulator to study fracture closure and proppant-settling/embedment processes during shut-in and production. This simulator implicitly couples the reservoir (rock deformation and porous flow), fracture (fracturing-fluid flow, proppant transport), and wellbore (slurry distribution, production) domains. During shut-in, a modified Barton-Bandis (Bandis et al. 1983) formula is used to describe the nonlinear relationship between the contact force and the residual fracture aperture considering the dynamic proppant spatial distribution and rock heterogeneity. During production, fracture conductivity is evaluated according to proppant distribution and further fracture closure caused by proppant crushing and embedment. A Newton-Raphson method is applied to solve the coupled system of equations. Results from the simulations clearly show that typical periods of shut-in after fracturing lead to the formation of proppant banks at the bottom of the fracture in low-permeability, low-leakoff formations. This can lead to near-wellbore tortuosity and poor connectiv

关键词： fracturing fluid surface area embedment injection equation proppant Simulation proppant mass proppant distribution unpropped fracture

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Finite element modelling for as-laid embedment of pipeline in clayey sediments

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OCEAN ENGINEERING 2020年 217卷 107963-107963页

作者： Zhao, Liang Wang, Dong Tian, Yinghui Fugro GeoConsulting Perth WA 6000 Australia Ocean Univ China Coll Environm Sci & Engn 238 Songling Rd Qingdao 266100 Peoples R China Qingdao Natl Lab Marine Sci & Technol Qingdao Peoples R China Univ Melbourne Melbourne Sch Engn Parkville Vic 3010 Australia

A numerical modelling technique for the estimation of as-laid pipeline embedment in clayey sediments is introduced in the paper. The process of pipe-laying is modelled numerically with the pipe-soil interaction defined using a nonlinear elasto-plastic model, therefore the soil resistance contributed by soil buoyancy can be well considered in the evaluation of as-laid pipeline embedment. The impact of the soil buoyancy in the estimate of as-laid embedment is then quantitatively assessed using the proposed numerical modelling technique, and the results show that the as-laid pipeline embedment can be significantly overestimated if the soil buoyancy is ignored in the analysis.

关键词： Pipelines Finite element method Clay Pipe laying embedment Buoyancy

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Swelling and embedment induced by sub- and super-critical-CO2 on the permeability of propped fractures in shale

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INTERNATIONAL JOURNAL OF COAL GEOLOGY 2020年 225卷 103496-103496页

作者： Hou, Lei Elsworth, Derek Geng, Xueyu Univ Warwick Sch Engn Coventry CV4 7AL W Midlands England Penn State Univ Energy & Mineral Engn EMS Energy Inst University Pk PA 16802 USA Penn State Univ G3 Ctr University Pk PA 16802 USA

Swelling and embedment exert significant influence on the evolution of permeability in propped fractures, potentially consuming significant proportions of the original gain in permeability. We measure the evolution of permeability in propped fractures of shale to both adsorbing CO2 and non-adsorbing He - accommodating the impacts of aperture change due to proppant pack compaction and both reversible and irreversible modes of embedment. A linear relation between pressure and log-permeability is obtained for He, representing the impact of effective stresses in proppant pack compaction, alone. Permeability change with pressure is always concave upwards and U-shaped for gaseous subcritical CO2 and W-shaped for supercritical CO2. One exception is for liquid CO2 at high injection pressure where effective stress effects and swelling contribute equally to the change in permeability and result in a linear curve with the lowest permeability. Approximately similar to 50-70% of the permeability recovers from the recovery of swelling after the desorption of CO2. The magnitude of swelling is recovered from measurements of permeability change and ranges from 0.005 to 0.06 mm, which contributes similar to 9-56% of the total swelling and induced embedment as evaluated from the adsorbed mass. Swelling also increases embedment by a factor of similar to 1.84-1.93 before and after the injection of CO2. A new calibration equation representing swelling and induced embedment is generated accommodating Langmuir isothermal sorption and verified against experiments on rocks both admitting and excluding swelling and embedment and for various sorbing and non-sorbing gases. Stability and accuracy of the predictions demonstrate the universality of the approach that may be applied to both enhanced gas recovery and CO2 sequestration.

关键词： Swelling embedment Propped shale fracture Permeability Carbon dioxide

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