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Chinese Physics B 2024年第1期33卷 468-476页

作者：赵志强刘金霞刘建宇崔志文 College of Physics Jilin UniversityChangchun 130012China

In-situ stress is a common stress in the exploration and development of oil reservoirs. Therefore, it is of great significance to study the propagation characteristics of borehole acoustic waves in fluid-saturated porous media under *** on the acoustoelastic theory of fluid-saturated porous media, the field equation of fluid-saturated porous media under the conditions of confining pressure and pore pressure and the acoustic field formula of multipole source excitation in open hole are given. The influences of pore pressure and confining pressure on guided waves of multipole borehole acoustic field in fluid-saturated porous media are investigated. The numerical results show that the phase velocity and excitation intensity of guided wave increase significantly under the confining pressure. For a given confining pressure, the phase velocity of the guided wave decreases with pore pressure increasing. The excitation intensity of guided wave increases at low frequency and then decreases at high frequency with pore pressure increasing, except for that of Stoneley wave which decreases in the whole frequency range. These results will help us get an insight into the influences of confining pressure and pore pressure on the acoustic field of multipole source in borehole around fluid-saturated porous media.

关键词： confining pressure pore pressure fluid-saturated porous media multipole borehole acoustic field

Mechanical properties of thermal aged HTPB composite solid propellant under confining pressure

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Defence Technology（防务技术） 2022年第4期18卷 618-625页

作者： Zhe-jun Wang Hong-fu Qiang 206 Staff Room Xi’an Hi-Tech InstituteXi'an710025PR China

With the purpose of investigating the effects of confining pressure and aging on the mechanical properties of Hydroxyl-terminated polybutadiene(HTPB)based composite solid propellant,tensile tests of thermal accelerated aged propellant samples under room temperature and different confining pressure conditions were performed through the use of a self-made confining pressure device and conventional testing ***,the maximum tensile stressσmand the corresponding strainεm for the propellant under different test conditions were obtained and *** results indicate that confining pressure and aging can significantly affect the mechanical properties of HTPB propellant,and the coupled effects are very *** the one hand,the stressσmincreases as a whole when confining pressure becomes higher or thermal aging time ***,this stress is more sensitive to aging with increasing confining *** are almost three regions in the stress increments(σm P-σm0)/σm0and thermal aging time curves for HTPB *** maximum value of the stress increment(σm P-σm0)/σm0for the propellant is about 98%at 7.0 MPa and 170 *** the other hand,the strainεm decreases with increasing thermal aging time under the whole confining pressure ***,the variation of this strain with confining pressure is more complex at various thermal aging time,which is different from that of unaged solid propellant in previous *** addition,this strain is slightly less sensitive to aging as the confining pressure ***,there is also a critical confining pressure in this investigation,whose value is between 0.15 MPa and 4.0 *** this critical pressure,the trends of the stressσmand the corresponding strainεm all ***,there are some critical thermal aging time for the stress increment(σm P-σm0)/σm0and strain increment(εm P-εm0)/εm0of HTPB propellant in this investigation,which are about at 35,50 and 170 ***,based on the tw

关键词： Thermal accelerated aging confining pressure Hydroxyl-terminated polybutadiene propellant Mechanical properties Strength criterion

Effects of confining pressure and temperature on strength and deformation behavior of frozen saline silty clay

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Research in Cold and Arid Regions 2023年第1期15卷 1-10页

作者： Gang Wu GuoYu Li Hui Bing Dun Chen YaPeng Cao LiYun Tang HaiLiang Jia State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China Da Xing'anling Observation and Research Station of Frozen-Ground Engineering and Environment Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesJiagedaqiHeilongjiang 165000China University of Chinese Academy of Sciences Beijing100049China School of Architecture and Civil Engineering Xi'an University of Science and TechnologyXi'anShanxi710000China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouJiangsu 221116China

Buildings are always affected by frost heave and thaw settlement in cold regions,even where saline soil is *** paper describes the triaxial testing results of frozen silty clay with high salt content and examines the in-fluence of confining pressure and temperature on its mechanical *** triaxial compression tests were conducted under different confining pressures(0.5–7.0 MPa)and temperatures(-6℃,-8℃,-10℃,and-12℃).The test results show that when the confining pressure is less than 1 MPa,the frozen saline silty clay is dominated by brittle behavior with the X-shaped dilatancy failure *** the confining pressure increases,the sample gradually transitions from brittle to plastic *** strength of frozen saline silty clay rises first and then decreases with increasing confining *** improved Duncan-Chang hyperbolic model can describe the stress-strain relationship of frozen saline silty *** the parabolic strength criterion can be used to describe the strength evolution of frozen saline silty *** function relation of strength parameters with temperature is obtained by fitting,and the results of the parabolic strength criterion are in good agreement with the experimental results,especially when confining pressure is less than 5 ***,the study has important guiding significance for design and construction when considering high salinity soil as an engineering material in cold regions.

关键词： Super saline soil Frozen saline soil Triaxial compression test confining pressure Strength Deformation characteristics

Dynamic experiment and numerical simulation of frozen soil under confining pressure

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Acta Mechanica Sinica 2020年第6期36卷 1302-1318,I0004页

作者： W.R.Tang Z.W.Zhu T.T.Fu Z.W.Zhou Z.H.Shanggua Applied Mechanics and Structural Safety Key Laboratory of Sichuan Province School of Mechanics and EngineeringSouthwest Jiaotong UniversityChengdu610036China Northwest Institute of Eco-Environment and Resources State Key Laboratory of Frozen Soil EngineeringChinese Academy of SciencesLanzhou730000China

With the development of cold region engineering,it is crucial to study the mechanical properties of frozen *** practice,frozen soil is inevitably subject to impact loading,making the study of frozen soil under impact loading necessary for engineering in cold *** split–Hopkinson pressure bar(SHPB)is an important experimental means for obtaining the dynamic performance of *** this study,an SHPB experiment was conducted on frozen soil under confining *** frozen soil exhibited an evident strain rate effect and temperature effect under confining *** SHPB experiment on frozen soil under confining pressure was simulated numerically using LS-DYNA software and the Holmquist–Johnson–Cook(HJC)material model.A loading simulation with passive confining pressure and active confining pressure was completed by adding an aluminum sleeve and applying a constant *** simulation results obtained using the above methods were in good agreement with the experimental *** strength of the frozen soil under confining pressure was greater than that of the uniaxial impact,and there was an evident confining pressure ***,the confining pressure provided by passive confinement was larger than that provided by active *** passive confining pressure energy absorption efficiency was higher than for the active confining pressure due to the need to absorb more energy under the same damage *** frozen soil exhibited viscoplastic failure characteristics under confining pressure.

关键词： Frozen soil-Dynamic experiment confining pressure Split-Hopkinson pressure bar Numerical simulation

Erosion characteristics and mechanism of the self-resonating cavitating jet impacting aluminum specimens under the confining pressure conditions

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Journal of Hydrodynamics 2020年第2期32卷 375-384页

作者： Hua-lin Liao Sheng-li Zhao Yan-feng Cao Lei Zhang Can Yi Ji-lei Niu Li-hong Zhu School of Petroleum Engineering China University of PetroleumQingdao266580China State Key Laboratory of Offshore Oil Exploitation Beijing100028China Huanghe Drilling Co. Shengli Engineering Co.SINOPECDongying257000China Orion Energy International Co. LtdBeijing100101China

In order to study the effects of the confining pressure on the erosion characteristics of the self-resonating cavitating jet under wellbore and deep-water conditions,experiments are conducted on aluminum specimens impinged by the organ pipe cavitation nozzle and the conical nozzle with the confining pressure in the range 0 MPa–10.0 ***,through the numerical simulation of the collapsing process of the cavitation bubble and the noise test,the cavitation erosion mechanism is *** experimental results show that the optimal standoff distance and the confining pressure can be obtained for the maximum erosion quantities,and the optimal standoff distance is 5 to 7 times greater than the equivalent nozzle outlet diameter and the confining pressure is about 2.0 *** the same conditions,the erosion caused by the cavitation nozzle is up to 2 times larger than that caused by the conical *** to the numerical simulation and the noise test,the cavitation erosion on the aluminum specimens is mostly caused by mechanical forces due to the high-frequency pressure pulse generated during the collapse of cavitation bubbles,while just a small part is caused by micro-jets.

关键词： Cavitating jet cavitation erosion confining pressure nozzle

Research on the influences of confining pressure and strain rate on NEPE propellant:Experimental assessment and constitutive model

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Defence Technology（防务技术） 2021年第5期17卷 1764-1774页

作者： Hui Li Jin-sheng Xu Jia-ming Liu Ting-yu Wang Xiong Chen Hong-wen Li School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China Technology Center Jinxi Industries Group CorporationTaiyuan030027China

In order to study the influences of confining pressure and strain rate on the mechanical properties of the Nitrate Ester Plasticized Polyether(NEPE)propellant,uniaxial tensile tests were conducted using the selfmade confining pressure system and material testing *** stress-strain responses of the NEPE propellant under different confining pressure conditions and strain rates were obtained and *** results show that confining pressure and strain rate have a remarkably influence on the mechanical responses of the NEPE *** confining pressure increases(from 0 to 5.4 MPa),the maximum tensile stress and ultimate strain increase *** the coupled effects of confining pressure and strain rate,the value of the maximum tensile stress and ultimate strain at 5.4 MPa and 0.0667 s^(-1)is 2.03 times and 2.19 times of their values under 0 MPa and 0.00333 s^(-1),***,the influence mechanism of confining pressure on the NEPE propellant was ***,based on the viscoelastic theory and continuous damage theory,a nonlinear constitutive model considering confining pressure and strain rate was *** damage was considered to be rate-dependent and *** constitutive model was validated by comparing experimental data with predictions of the constitutive *** whole maximum stress errors of the model predictions are lower than 4%and the corresponding strain errors are lower than 7%.The results show that confining pressure can suppress the damage initiation and evolution of the NEPE propellant and the nonlinear constitutive model can describe the mechanical responses of the NEPE propellant under various confining pressure conditions and strain *** research can lay a theoretical foundation for analyzing the structural integrity of propellant grain accurately under working pressure loading.

关键词： confining pressure Strain rate NEPE propellant Constitutive model Damage

Anisotropic Rock Poroelasticity Evolution in Ultra-low Permeability Sandstones under Pore pressure,confining pressure,and Temperature:Experiments with Biot's Coefficient

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Acta Geologica Sinica(English Edition) 2021年第3期95卷 937-945页

作者： DU Shuheng State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

This study aimed to show anisotropic poroelasticity evolution in ultra-low permeability reservoirs under pore pressure,confining pressure,and *** groups of experiments examining Biot's coefficient under different conditions were carried *** showed that Biot's coefficient decreased with increased pore pressure,and the variation trend is linear,but the decreasing rate is variable between ***'s coefficient increased with increased confining pressure;the variation trend is linear,but the increasing rate varies by material as ***,Biot's coefficient remains stable with increased ***,clay mineral content,particle arrangement,and pore arrangement showed impacts on Biot's *** strong hydrophilic clay minerals,expansion in water could result in a strong surface adsorption reaction,which could result in an increased fluid bulk modulus and higher Biot's *** skeleton minerals with strong lipophilicity,such as quartz and feldspar,increased oil saturation will also result in an adsorption reaction,leading to increased fluid bulk modulus and a higher Biot's *** study's conclusions provide evidence of poroelasticity evolution of ultra-low permeability and help the enhancing oil recovery(EOR)process.

关键词： Biot's coefficient ultra-low permeability pore pressure confining pressure temperature

Experimental Study of confining pressure Initiated by Tectonic Force

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Journal of China University of Geosciences 2004年第2期15卷 162-166页

作者： LuGuxian MaRui LiuRuixun WangFangzheng GuoChusun InstituteofGeomechanics ChineseAcademyofGeologicalSciencesBeijing100081 CollegeofEarthSciences JilinUniversityChangchun130061China SchoolofEarthandSpaceScience.s PekingUniversityBeijing100871China FacultyofEarthSciences ChinaUniversityofGeosciencesWuhan430074China InstituteofGeomechanics ChineseAcademyofGeologicalSciencesBeijing100081China

An experimental study of the confining pressure, i.e. additional hydrostatic pressure initiated by the tectonic force is presented. The experimental progress is that the σ 1 is gradually increasing from 0 in a limiting movement ( ε 1=0) in the σ 1 direction and the speed rate of the accelerating load is 0.4 MPa·s -1 in the lateral and level directions. When σ 2= σ 3confining pressure which is gradually increasing with σ 2= σ 3 before it reaches 380 MPa in an experiment. It is supposed that the horizontal force is almost all transformed into the confining pressure with the increase of the creep deformation of rocks.

关键词： tectonic force confining pressure additional hydrostatic pressure experiment.

Research on confining pressure Sensitivity for Permeability and Slippage Effect of the Longmaxi Formation Shale in the North of Guizhou

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Research on Confining Pressure Sensitivity for Permeability ...

Estimating shear strength of high-level pillars supported with cemented backfilling using the HoekeBrown strength criterion

作者： Rui LUO Shouchun DENG Xiaofang JIANG State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences University of Chinese Academy of Sciences

The Longmaxi Formation shale in the Xishui area of northern Guizhou is a promising target for shale gas *** using a self-developed gas permeameter that considers temperature and pressure,the apparent permeability of shale samples in this shale reservoir was tested,and the slip factor was fitted using the Klinkenberg permeability correction factor *** results show that the confining pressure has a greater impact on the absolute permeability and slippage factor of the shale *** the confining pressure is in the range of 1.5 MPa to 10 MPa,the absolute permeability varies from 1.54 E-17 m to 2.35 E-21 m,and the slip factor varies from 0.37 MPa to 0.11 *** shale samples have a significant slippage effect when the confining pressure is less than 5 MPa,and the slippage effect contributes more than 19% to the *** the confining pressure is more than 5 MPa and less than 10 MPa,the influence of the slippage effect is relatively weakened,but the contribution rate is still greater than 9%.

关键词： Northern Guizhou Longmaxi Formation Shale Permeability Slippage Effect confining pressure

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 454-469页

作者： Kaizong Xia Congxin Chen Xiumin Liu Yue Wang Xuanting Liu Jiahao Yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

Deep metal mines are often mined using the high-level pillars with subsequent cementation backfilling(HLSCB)mining *** the design stage,it is therefore important to have a reasonable method for determining the shear strength of the high-level pillars(*** and internal friction angle)when they are supported by cemented *** this study,a formula was derived for the upper limit of the confining pressure σ3max on a high-level pillar supported by cemented backfilling in a deep metal mine.A new method of estimating the shear strength of such pillars was then proposed based on the Hoek eBrown failure *** analysis indicates that the horizontal stress σhh acting on the cemented backfill pillar can be simplified by expressing it as a constant value.A reasonable and effective value for σ3max can then be *** value of s3max predicted using the proposed method is generally less than 3 *** this range,the shear strength of the high-level pillar is accurately calculated using the equivalent MohreCoulomb *** proposed method can effectively avoid the calculation of inaccurate shear strength values for the high-level pillars when the original HoekeBrown criterion is used in the presence of large confining pressures,*** situation in which the cohesion value is too large and the friction angle is too small can effectively be *** proposed method is applied to a deep metal mine in China that is being excavated using the HLSCB *** shear strength parameters of the high-level pillars obtained using the proposed method were input in the numerical *** numerical results show that the recommended level heights and sizes of the high-level pillars and rooms in the mine are rational.

关键词： Deep metal mines High-level pillars HoekeBrown strength criterion Cemented backfilling confining pressure Shear strength