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Impacts of anisotropy coefficient and porosity on the thermal conductivity and P-wave velocity of calcarenites used as building materials of historical monuments in Morocco

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第7期15卷 1687-1699页

作者： Abdelaali Rahmouni Abderrahim Boulanouar Younes El Rhaffari Mohammed Hraita Aziz Zaroual Yves Géraud Jamal Sebbani Abdellah Rezzouk Bassem S.Nabawy Laboratory of Solid State physics Department of PhysicsFaculty of Science Dhar El MahrazSidi Mohamed Ben Abdellah UniversityFezMorocco Laboratory of Applied Sciences National School of Applied SciencesAbdelmalek Essaadi UniversityAl HoceimaMorocco Laboratory of Civil Engineering and Environment Higher School of Technology of SaléMohammed V UniversityRabatMorocco Department of physics Higher Normal SchoolMohammed V UniversityRabatMorocco Laboratory of Materials Nanotechnologies and EnvironmentFaculty of ScienceMohammed V UniversityRabatMorocco University of Lorraine ENSGUMR 7359-GeoRessourcesNancyFrance Mechanics and Materials Team Faculty of ScienceMohammed V UniversityRabatMorocco Geophysical Sciences Department National Research CentreCairoEgypt

It is essential to study the porosity,thermal conductivity,and P-wave velocity of calcarenites,as well as the anisotropy coefficients of the thermal conductivity and P-wave velocity,for civil engineering,and conservation and restoration of historical monuments.This study focuses on measuring the thermal conductivity using the thermal conductivity scanning(TCS)technique and measuring the p-wave ve-locity using portable equipment.This was applied for some dry and saturated calcarenite samples in the horizontal and vertical directions(parallel and perpendicular to the bedding plane,respectively).The calcarenites were selected from some historical monuments in Morocco.These physical properties were measured in the laboratory to find a reliable relationship between all of these properties.As a result of the statistical analysis of the obtained data,excellent linear relationships were observed between the porosity and both the thermal conductivity and porosity.These relationships are characterized by relatively high coefficients of determination for the horizontal and vertical samples.Based on the thermal conductivity and P-wave velocity values in these two directions,the anisotropy coefficients of these two properties were calculated.The internal structure and the pore fabric of the calcarenite samples were delineated using scanning electron microscopy(SEM),while their chemical and mineral compositions were studied using the energy dispersive X-ray analysis(EDXA)and X-ray diffraction(XRD)techniques.

关键词： Moroccan historical monuments Calcarenite Thermal conductivity P-wave velocity porosity Anisotropy coefficient Water saturation

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A method to model the effect of pre-existing cracks on P-wave velocity in rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 493-506页

作者： Haimeng Shen Xiaying Li Qi Li Haibin Wang State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

Crack closure is one of the reasons inducing changes of P-wave velocity of rocks under compression.In this context,a method is proposed to investigate the relationships among P-wave velocity,pre-existing cracks,and confining pressure based on the discrete element method(DEM).pre-existing open cracks inside the rocks are generated by the initial gap of the flat-joint model.The validity of the method is evaluated by comparing the P-wave velocity tested on a sandstone specimen with numerical result.As the crack size is determined by the diameter of particles,the effects of three factors,i.***.number,aspect ratio,and orientation of cracks on the P-wave velocity are discussed.The results show that P-wave velocity is controlled by the(i.***.number) of open micro-cracks,while the closure pressure is determined by the aspect ratio of crack.The reason accounting for the anisotropy of P-wave velocity is the difference in crack number in measurement paths.Both of the number and aspect ratio of cracks can affect the responses of P-wave velocity to the applied confining pressure.Under confining pressure,the number of open cracks inside rocks will dominate the lowest P-wave velocity,and the P-wave velocity of the rock containing narrower cracks is more sensitive to the confining pressure.In this sense,crack density is difficult to be back-calculated merely by P-wave velocity.The proposed method offers a means to analyze the effect of pre-existing cracks on P-wave velocity.

关键词： pre-existing cracks P-wave velocity Discrete element method(DEM) Anisotropic rock

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Inconsistency of changes in uniaxial compressive strength and P-wave velocity of sandstone after temperature treatments

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第1期13卷 143-153页

作者： Jinyuan Zhang Yanjun Shen Gengshe Yang Huan Zhang Yongzhi Wang Xin Hou Qiang Sun Guoyu Li College of Architecture and Civil Engineering Xi’an University of Science and TechnologyXi’an710054China College of Geology and Environment Xi’an University of Science and TechnologyXi’an710054China Geological Research Institute for Coal Green Mining Xi’an University of Science and TechnologyXi’an710054China State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou730000China

It is generally accepted that the uniaxial compressive strength(UCS)and P-wave velocity of rocks tend to decrease simultaneously with increasing temperature.However,based on a great number of statistical data and systematic analysis of the microstructure variation of rocks with temperature rising and corresponding propagation mechanism of elastic wave,the results show that(1)There are three different trends for the changes of UCS and P-wave velocity of sandstone when heated from room temperature(20C or 25C)to 800C:(i)Both the UCS and P-wave velocity decrease simultaneously;(ii)The UCS increases initially and then decreases,while the P-wave velocity decreases continuously;and(iii)The UCS increases initially and then fluctuates,while the P-wave velocity continuously decreases.(2)The UCS changes at room temperaturee400C,400Ce600C,and 600Ce800C are mainly attributed to the discrepancy of microstructure characteristics and quartz content,the transformation plasticity of clay minerals,and the balance between the thermal cementation and thermal damage,respectively.(3)The inconsistency in the trends of UCS and P-wave velocity changes is caused by the change of quartz content,phase transition of water and certain minerals.

关键词： Sandstone High temperature Uniaxial compressive strength(UCS) P-wave velocity Distortion Mineralogy

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Classification and assessment of rock mass parameters in Choghart iron mine using P-wave velocity

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第2期9卷 318-328页

作者： Mohammadreza Hemmati Nourani Mohsen Taheri Moghadder Mohsen Safari Department of Mining and Metallurgy Yazd UniversityYazdIran Department of Mining Engineering Shahid Bahonar University of KermanKermanIran Department of Mining Engineering Birjand University of TechnologyBirjandIran

Engineering rock mass classification,based on empirical relations between rock mass parameters and engineering applications,is commonly used in rock engineering and forms the basis for designing rock structures.The basic data required may be obtained from visual observation and laboratory or field tests.However,owing to the discontinuous and variable nature of rock masses,it is difficult for rock engineers to directly obtain the specific design parameters needed.As an alternative,the use of geophysical methods in geomechanics such as seismography may largely address this problem.In this study,25 seismic profiles with the total length of 543 m have been scanned to determine the geomechanical properties of the rock mass in blocks Ⅰ,Ⅲ and Ⅳ-2 of the Choghart iron mine.Moreover,rock joint measurements and sampling for laboratory tests were conducted.The results show that the rock mass rating（RMR） and Q values have a close relation with P-wave velocity parameters,including P-wave velocity in field(V;).P-wave velocity in the laboratory(V;) and the ratio of V;V;(i.e.K;= V;/V;.However,Q value,totally,has greater correlation coefficient and less error than the RMR,In addition,rock mass parameters including rock quality designation（RQD）,uniaxial compressive strength（UCS）,joint roughness coefficient（JRC） and Schmidt number（RN） show close relationship with P-wave velocity.An equation based on these parameters was obtained to estimate the P-wave velocity in the rock mass with a correlation coefficient of 91%.The velocities in two orthogonal directions and the results of joint study show that the wave velocity anisotropy in rock mass may be used as an efficient tool to assess the strong and weak directions in rock mass.

关键词： Rock mass classification P-wave velocity Q system Rock mass rating(RMR) Geophysical methods

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velocity structure and radial anisotropy beneath the northeastern Tibetan plateau revealed by eikonal equation-based teleseismic p-wave traveltime tomography

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Science China Earth Sciences 2022年第5期65卷 824-844页

作者： Mengyang LI Shaolin LIU Dinghui YANG Xiwei XU Wenhao SHEN Chaodi XIE Wenshuai WANG Shuxin YANG National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China School of Earth Sciences Yunnan UniversityKunming 650091China Department of Mathematical Sciences Tsinghua UniversityBeijing 100084China School of Mathematics and Statistics Ningxia UniversityYinchuan 750021China

The northeastern Tibetan plateau serves as the frontier for the northeastward expansion of the plateau.In this area,the Tibetan plateau interacts with the surrounding blocks,such as the Alxa Block,the Ordos Block,the Kunlun-West Qinling belt and the Sichuan Basin.Because of this expansion and interaction,this area suffers from intense deformation.At present,the evolution and deformation mechanisms of the northeastern Tibetan plateau remain controversial.To provide new insights into these mechanisms,in this study,we conduct tomography of the P-wave velocity and radial anisotropy structures beneath the northeastern Tibetan plateau.We choose a total of 667 teleseismic earthquakes from August 2006 to October 2020.waveforms of these earthquakes were recorded by 921 broadband seismic stations in the northeastern Tibetan plateau and surrounding areas.We first perform cross-correlation on waveforms of each station pair and obtain 770,749 p-wave traveltime differences.Then,we invert the differential traveltime data by applying eikonal equation-based teleseismic tomography.Finally,the P-wave velocity and radial anisotropy structures at depths from 30 to 800 km below the northeastern Tibetan plateau are obtained.Our tomographic model shows clear low-velocity anomalies and positive radial anisotropy in the lower crust under the northeastern Qilian orogen,the northeastern Songpan-Ganzi belt and the western Qinling fold zone.These features are integrated to demonstrate the existence of lower crustal flow in the study area.prominent low-velocity anomalies and positive radial anisotropy are found in the uppermost mantle beneath the Qilian orogen,the northeastern Songpan-Ganzi belt and western Qinling fold zone.These characteristics are combined to infer a weak lithosphere and horizontal asthenospheric flow under these tectonic units.Both the Ordos Block and the Sichuan Basin exhibit clear high-velocity anomalies and negative radial anisotropy in the uppermost mantle,thereby reflecting the high mechanical strength of the lithosph

关键词： Northeastern Tibetan plateau Tomography P-wave velocity Radial anisotropy structure Indian plate

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Crustal P-wave velocity structure of the Longmenshan region and its tectonic implications for the 2008 Wenchuan earthquake

Crustal P-wave velocity structure of the Longmenshan region ...

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中国科学院地质与地球物理研究所第11届（2011年度）...

作者： LI ZhiWei~(1*),Xu Yi~1,Huang RunQiu~2,Hao TianYao~1,Xu Ya~1,Liu JingSong~1 & Liu JianHua~1 Key Laboratory of petroleum Resources Research,Institute of Geology and Geophysics,Chinese Academy of Sciences, Beijing 100029,China State Key Laboratory of Geohazard prevention and Geoenvironment protection,Chengdu University of Technology,Chengdu 610059,China

The P-wave velocity structure of the crust in the Longmenshan region has been imaged by seismic travel time tomography using local and regional first p-wave arrivals recorded from 2000 to 2008.The tomographic model provides a way to analyze the deep tectonics of the Longmenshan fault belt and the tectonic implications for the 2008 M8.0 Wenchuan earthquake.The P-wave velocity images indicate that the initial rupture site and focal depth of the Wenchuan earthquake,together with the direction of rupture propagation,closely relate to the crustal structure of the Longmenshan region.The pengguan massif to the west of the Longmenshan fault belt is characterized by high velocity anomalies,suggesting that the crust has a strong strain strength that can accumulate large stresses over a long period.The M8.0 Wenchuan earthquake is located at the southwestern end of the pengguan massif and the western edge of the Sichuan Basin.The collision between the pengguan massif and the Sichuan Basin becomes the primary reason for the occurrence of the M8.0 Wenchuan earthquake.To the north of Wenchuan, the occurrence and propagation of rupture benefit from low velocity anomalies along the Longmenshan fault belt;whereas to the south of Wenchuan,the brittle rupture can occur with more difficulty in relatively weak crust with low velocities.This may be one of the reasons for the absence of aftershocks to the south of Wenchuan,and the rupture induced by the M8.0 Wenchuan earthquake propagating from the north to the south along the Longmenshan fault belt.The deep geodynamics of the M8.0 Wenchuan earthquake may occur due to the discrepancy of crustal structures on the two sides of the Longmenshan fault belt. Ductile deformation and crustal flow can easily occur in the weak middle-lower crust beneath the Songpan-Garze orogenic belt. The eastward movement of the Tibetan plateau is obstructed by the rigid lithosphere of the Sichuan Basin,and then the thickening of the middle-lower crust and vertical deformation occur in the crust of the Longmens

关键词： Longmenshan orogenic belt Wenchuan earthquake P-wave velocity Crustal structure travel time tomography

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P-wave velocity in Rocks of Dabieshan, China at High pressure and High Temperature: Constraints for Composition of Lower Crust and Crust-Mantle Recycling

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Journal of Earth Science 1999年第4期18卷 295-298页

作者： Zhao Zhidan Zhou Wenge Xie Hongsen Guo Jie Xu Zuming(Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002)Zhang Zeming(Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037) Institute of Geochemistry Chinese Academy of SciencesGuiyang 550002 Institute of Geology Chinese Academy of Geological SciencesBeijing 100037

p-wave velocities in the rocks of Dabieshan, central China were measured at pressures up to 5.0 Gpa and temperatures up to 1 300℃. The ultrahigh pressure eclogites have the highest density and P-wave velocity (Vp) and lower anisotropy. pressure derivatives of the eclogites range from 0. 22 to 0. 33 km. s-1 Gpa-1. Average temperature derivative of the eclogites is - 3. 41×10-4 km. s-1. °C -1. The density and Vp of the eclogites imply that there will be two united possibilities related to crust-mantle recycling after the eclogite formed in the deep lithosphere. One is that some eclogites in the deep lithosphere were detached and sunk into deeper mantle due to their denser density. Another is that some eclogites returned to the crust and exposed to the surface.Small amounts (p crust beneath Dabieshan based on our calculation.

关键词： eclogite P-wave velocity density high pressure high temperature lower crust

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Acoustic response characteristics and sensitivity of briquette and raw coal under temperature and pressure control

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Frontiers of Earth Science 2023年第1期17卷 170-179页

作者： Hewei ZHANG Jian SHEN Kexin LI Xiaojie FANG Ziwei WANG Lei DU Key Laboratory of Coalbed Methane Resources and Reservoir Formation process(Ministry of Education) China University of Mining and TechnologyXuzhou 221008China School of Resources and Geosciences China University of Mining and TechnologyXuzhou 221116China Huabei Oilfield CBM Branch Company Changzhi 046000China Shaanxi Coalfield Geophysical Exploration and Mapping Co. Ltd.Xi᾽an 710000China

Acoustic testing is a widely used technique to measure the coal mechanical properties under high temperature and pressure in situ conditions.This study compared the acoustic wave characteristics of briquette and raw coal under various temperature and pressure conditions.The results show that the longitudinal wave velocity(Vp)decreases with an increasing vitrinite content.A large number of the vitrinite content enhances the process in which the temperature and pressure changed the Vp.The Vp of briquette decreases approximately linearly with the temperature compared to raw coal.The Vp of raw coal experiences initially a rapid,then gradual,and finally the moderate increasing trend with the increase in confining pressure.However,in briquette,the Vp increases approximately linearly with the confining pressure.The results indicate that the Vp is more sensitive to temperature under low confining pressure and peaks at 50℃−60℃ than high confining pressure.However,the Vp is less sensitive to temperature under higher confining pressure,and the positive effect of high confining pressure is dominant.Understanding the mechanical properties of coal under high pressure and temperature develops better insight into coalbed methane(CBM)exploration from deep reservoirs.

关键词： high-rank coal P-wave velocity temperature pressure microscopic components sensitivity

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Shallow crustal velocity structures revealed by active source tomography and fault activities of the Mianning–Xichang segment of the Anninghe fault zone, Southwest China

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Earth and planetary physics 2022年第2期6卷 204-212页

作者： XiHui Shao HuaJian Yao Ying Liu HongFeng Yang BaoFeng Tian LiHua Fang Laboratory of Seismology and physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaMengcheng Hefei 233500China CAS Center for Excellence in Comparative planetology University of Science and Technology of ChinaHefei 230026China Earth System Science programme Faculty of ScienceThe Chinese University of Hong KongHong Kong 999077China Shenzhen Research Institute The Chinese University of Hong KongShenzhen 518057China Institute of Geophysics China Earthquake AdministrationBeijing 100089China

The Anninghe fault is a large left-lateral strike-slip fault in southwestern China. It has controlled deposition and magmatic activities since the proterozoic, and seismic activity occurs frequently. The Mianning-Xichang segment of the Anninghe fault is a seismic gap that has been locked by high stress. Many studies suggest that this segment has great potential for large earthquakes(magnitude >7). We obtained three vertical velocity profiles of the Anninghe fault(between Mianning and Xichang) based on the inversion of p-wave first arrival times. The travel time data were picked from seismograms generated by methane gaseous sources and recorded by three linearly distributed across-fault dense arrays. The inversion results show that the P-wave velocity structures at depths of 0-2 km corresponds well with the local lithology. The Quaternary sediments have low seismic velocities, whereas the igneous rocks,metamorphic rocks, and bedrock have high seismic velocities. We then further discuss the fault activities of the two fault branches of the Anninghe fault in the study region based on small earthquakes(magnitudes between ML 0.5 and ML 2.5) detected by the Xichang array.The eastern fault branch is more active than the western branch and that the fault activities in the eastern branch are different in the northern and southern segments at the border of 28°21′N. The high-resolution models obtained are essential for future earthquake rupture simulations and hazard assessments of the Anninghe fault zone. Future studies of velocity models at greater depths may further explain the complex fault activities in the study region.

关键词： Anninghe fault zone shallow crust P-wave velocity methane gaseous source fault activity

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velocity-porosity relationships in hydrate-bearing sediments measured from pressure cores,Shenhu Area,South China Sea

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China Geology 2022年第2期5卷 267-275页

作者： Lin Lin Jun Cao Jin Qian Jiu-jing Shang Wei Zhang Jin-gan Lu Jin-qiang Liang Guangzhou Marine Geological Survey China Geological SurveyMinistry of Natural ResourcesGuangzhou 510760China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Institution of Oceanology Chinese Academy of SciencesQingdao 266071China

Evaluating velocity-porosity relationships of hydrate-bearing marine sediments is essential for characterizing natural gas hydrates below seafloor as either a potential energy resource or geohazards risks.Four sites had cored using pressure and non-pressure methods during the gas hydrates drilling project(GMGS4)expedition at Shenhu Area,north slope of the South China Sea.Sediments were cored above,below,and through the gas-hydrate-bearing zone guided with logging-while-drilling analysis results.Gamma density and P-wave velocity were measured in each pressure core before subsampling.Methane hydrates volumes in total 62 samples were calculated from the moles of excess methane collected during depressurization experiments.The concentration of methane hydrates ranged from 0.3%to 32.3%.The concentrations of pore fluid(25.44%to 68.82%)and sediments(23.63%to 54.28%)were calculated from the gamma density.The regression models of P-wave velocity were derived and compared with a global empirical equation derived from shallow,unconsolidated sediments data.The results were close to the global trend when the fluid concentration is larger than the critical porosity.It is concluded that the dominant factor of P-wave velocity in hydrate-bearing marine sediments is the presence of the hydrate.Methane hydrates can reduce the fluid concentration by discharging the pore fluid and occupying the original pore space of sediments after its formation.

关键词： Natural gas hydrates(NGHs) Methane hydrate P-wave velocity porosity Saturation pressure-core NGHs exploration trial engineering Oil and gas exploration engineering Shenhu Area South China Sea

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