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学者姓名：范立峰
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Abstract ：
The seismic wave propagation properties of granite after thermal cycles were experimentally investigated. The granite specimens were subjected to a series of thermal cycles with different thermal cycling temperatures and numbers. Ultra-sonic and pendulum impact tests were performed on the gran-ite after thermal cycles. Subsequently, a theoretical study was introduced to explore the wave propagation coefficients of granite after thermal cycles. The effects of the thermal cycling number on the wave attenuation rate, wave velocity, attenu-ation coefficient, and wavenumber were discussed. The results indicate that the wave velocity and dynamic elastic modulus decrease as the number of thermal cycles increases and that the damage factor increases as the number of thermal cycles increases. However, the variations in wave velocity, dynamic elastic modulus, and damage factor are concentrated mainly in the first thermal cycle. The results further indicate that the wave propagation coefficients, attenuation coefficient, and wavenumber increase as the number of thermal cycles increases. However, they are not significantly influenced by the amplitude and wavelength of impact loading.
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| GB/T 7714 | Fan, Lifeng , Yang, Kaichao , Wang, Meng et al. Original Article Evaluation of postoperative bleeding control employing Surgicel: a clinical trial [J]. | GEOPHYSICS , 2023 , 88 (2) : G19-G27 . |
| MLA | Fan, Lifeng et al. "Original Article Evaluation of postoperative bleeding control employing Surgicel: a clinical trial" . | GEOPHYSICS 88 . 2 (2023) : G19-G27 . |
| APA | Fan, Lifeng , Yang, Kaichao , Wang, Meng , Chen, Su . Original Article Evaluation of postoperative bleeding control employing Surgicel: a clinical trial . | GEOPHYSICS , 2023 , 88 (2) , G19-G27 . |
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Abstract ：
The effects of joint spacing on the transmission characteristics of stress waves through layered composite rock masses were investigated. First, a model of layered composite rock masses containing multiple parallel joints with different media in front of and behind the joints was introduced to study multiple reflections between joints. Second, wave transmission through layered composite rock masses was investigated and compared with wave transmission through traditional layered homogeneous rock masses. Finally, the effects of joint spacing and wave impedance ratio on particle velocity transmission coefficient were discussed. The results indicate that for wave propagation through rock masses with the same joint spacing, the onset time and amplitude of the transmitted wave in layered composite rock masses are smaller than those in layered homogeneous rock masses. For wave transmission through rock masses with the same nondimensional joint spacing, the onset time of the transmitted wave in the layered composite rock masses is similar to that in the layered homogeneous rock masses, while the amplitude of the transmitted wave in the layered composite rock masses is smaller than that in the layered homogeneous rock masses. In addition, the particle velocity transmission coefficient first increases and then decreases to be constant as the joint spacing increases, while it continues to increase as the wave impedance ratio increases for wave transmission through both layered composite rock masses and layered homogeneous rock masses.
Keyword ：
joint spacing joint spacing layered composite rock masses layered composite rock masses wave transmission wave transmission nondimensional joint spacing nondimensional joint spacing transmission coefficient transmission coefficient
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| GB/T 7714 | Fan, Lifeng , Shi, Xiaoying , Wang, Meng et al. The effects of joint spacing on transmission characteristics of stress waves through layered composite rock masses [J]. | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS , 2023 , 48 (3) : 822-836 . |
| MLA | Fan, Lifeng et al. "The effects of joint spacing on transmission characteristics of stress waves through layered composite rock masses" . | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS 48 . 3 (2023) : 822-836 . |
| APA | Fan, Lifeng , Shi, Xiaoying , Wang, Meng , Yang, Qihao , Chen, Su . The effects of joint spacing on transmission characteristics of stress waves through layered composite rock masses . | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS , 2023 , 48 (3) , 822-836 . |
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Abstract ：
This study investigated theshear slip behavior and contact area evolution of rough rock discontinuities with impact shear load. First, the dynamic impact shear numerical simulation of rock samples with real rough rock discontinuities was carried out. Subsequently, the variety rule of slip displacement and velocity of rock discontinuity with impact velocity, confining stress and joint roughness coefficient (JRC) was studied. The variation in contact area and shear stress of rock discontinuity during shear was assessed. Finally, the effect of frictional force on the slip displacement and velocity and the effect of contact area and frictional force on the shear stress distribution were analyzed. The results showed that the slip displacement, velocity and shear stress are rate dependent. The slip displacement and velocity increase as the impact velocity increases and decrease as the confining stress and JRC increase. The contact area and shear stress distribution range of rock discontinuities decrease slightly as the impact velocity increases but increase significantly as the confining stress and JRC increase. The shear stress distribution range of rock discontinuities closely correlates with the contact area. The shear stress in the non-contact area is zero. The shear stress distribution range increases as the contact area increases. The average shear stress increases as the frictional force increases. Moreover, the slip displacement and velocity of rock discontinuities decrease linearly as the frictional force increases.
Keyword ：
rough rock discontinuities rough rock discontinuities slip characteristics slip characteristics contact area evolution contact area evolution dynamic shear behavior dynamic shear behavior
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| GB/T 7714 | Fan, Lifeng , Li, Han , Xi, Yan et al. Investigation of slip characteristics and contact area evolution of rough rock discontinuity under impact shear load [J]. | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS , 2023 , 48 (3) : 749-770 . |
| MLA | Fan, Lifeng et al. "Investigation of slip characteristics and contact area evolution of rough rock discontinuity under impact shear load" . | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS 48 . 3 (2023) : 749-770 . |
| APA | Fan, Lifeng , Li, Han , Xi, Yan , Wang, Meng . Investigation of slip characteristics and contact area evolution of rough rock discontinuity under impact shear load . | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS , 2023 , 48 (3) , 749-770 . |
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Abstract ：
This paper investigated the microstructure deterioration of sandstones under three commonly used freezing-thawing (F-T) cycle treatments and compared the thermal-induced damage caused by these F-T treatments. Firstly, a series of F-T cycle treatments were carried out on the sandstones by the three F-T methods namely freezing in water and thawing in water (W-W), freezing in air and thawing in water (A-W), and freezing in air and thawing in air (A-A), respectively. Then, computed tomography (CT) tests were performed to observe the variations in microdefects of sandstones from planar and spatial levels, which were quantitatively described by areal porosity and volumetric porosity. Moreover, the damage factor was introduced to describe the damage evolutions of sandstones under F-T cycles and compare the differences in microstructure deterioration induced by the three F-T treatments. Finally, a damage estimation model based on the simplest F-T treatment method (A-A) was established to estimate the damage degree of sandstones under the W-W and A-W treatments. The results showed that under the three F-T treatments, the microdefects of sandstones developed, the areal porosities, volumetric porosities, damage factors, and damage difference coefficients increased as the number of F-T cycles increased. However, the different F-T treatments had different effects on the microstructure deterioration of sandstones. As the number of cycles increased to 50, the W-W treatment caused the most serious damage to sandstone, followed by A-W and A-A treatments. In addition, the damage estimation model based on the A-A treatment can effectively estimate the damage degree of sandstones under W-W and A-W treatments.
Keyword ：
Damage and deterioration Damage and deterioration Estimation model Estimation model CT scanning CT scanning Microstructure Microstructure Three freezing-thawing treatments Three freezing-thawing treatments
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| GB/T 7714 | Fan, Lifeng , Qiu, Bei , Gao, Jingwei . Evaluation of microstructure deterioration inside sandstone under three different freezing-thawing cycle treatments [J]. | BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT , 2023 , 82 (5) . |
| MLA | Fan, Lifeng et al. "Evaluation of microstructure deterioration inside sandstone under three different freezing-thawing cycle treatments" . | BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT 82 . 5 (2023) . |
| APA | Fan, Lifeng , Qiu, Bei , Gao, Jingwei . Evaluation of microstructure deterioration inside sandstone under three different freezing-thawing cycle treatments . | BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT , 2023 , 82 (5) . |
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Abstract ：
The propagation properties of stress waves in rock masses are significantly affected by high temperature. This paper presents an experimental investigation on the frequency-spectrum characteristics of stress waves in hightemperature granites. The pendulum impact test was performed on high-temperature granite bars to generate stress waves. The frequency-spectrum variation of stress waves in high-temperature granites was investigated by adopting the discrete Fourier transform. The effects of temperature on both the spectral attenuation ratio and the average energy dissipation rate of the harmonic wave were discussed. The results show that frequency spectra of stress waves occur attenuation when stress waves propagate in high-temperature granites. The frequencyspectrum attenuation is more obvious in the granite with higher temperature. Moreover, the spectral attenuation ratio and the average energy dissipation rate of the harmonic wave are significantly affected by the high temperature. The spectral attenuation ratio and the average energy dissipation rate of the harmonic wave increase as temperature increases.
Keyword ：
Energy dissipation Energy dissipation Frequency spectrum Frequency spectrum Wave propagation Wave propagation Wave attenuation Wave attenuation High temperature High temperature
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| GB/T 7714 | Yang, Qihao , Fan, Lifeng , Du, Xiuli . Experimental investigation on the frequency-spectrum characteristic of stress wave propagation through thermally treated granite [J]. | INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES , 2023 , 170 . |
| MLA | Yang, Qihao et al. "Experimental investigation on the frequency-spectrum characteristic of stress wave propagation through thermally treated granite" . | INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES 170 (2023) . |
| APA | Yang, Qihao , Fan, Lifeng , Du, Xiuli . Experimental investigation on the frequency-spectrum characteristic of stress wave propagation through thermally treated granite . | INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES , 2023 , 170 . |
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Abstract ：
An economical and widely available raw material is essential for the application and populari-zation of geopolymer. Due to the vast reserves of natural clay, calcined natural clay is considered a cost-effective geopolymer raw material. The present study aims at developing a high-ductile engineered geopolymer composites (EGC) using calcined natural clay. Firstly, natural clay as a construction waste was ground and calcined, and the calcined natural clay was mixed with ground granulated blast furnaces slag (GGBFS) and polyvinyl alcohol (PVA) fiber to prepare geopolymer composite samples. Then, the mini slump and uniaxial tensile test were conducted on the geopolymer composite samples, and the digital image correlation technology (DIC) was used to further analyze the effect of the slag and fiber contents on the tensile behavior of EGC. Finally, the optimal slag and fiber contents for EGC with highest ductility were proposed. The results showed that the natural clay exhibited a certain reactivity after a thermal activation process due to the presence of a small amount of kaolinite. The tensile properties of geopolymer composites prepared by calcined natural clay were significantly enhanced with increasing fiber content. Meanwhile, the incorporation of slag could enhance the tensile properties, while excessive slag content decreased the tensile properties. The EGC with 10.0% slag content and 2.5% fiber content exhibited the highest ductility, with an ultimate tensile strength of 3.61 MPa and a tensile strain capacity of 6.59%.
Keyword ：
Digital image correlation Digital image correlation Tensile properties Tensile properties Polyvinyl alcohol fiber Polyvinyl alcohol fiber Calcined natural clay Calcined natural clay Engineered geopolymer composites Engineered geopolymer composites
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| GB/T 7714 | Zhong, W. L. , Zhang, Y. H. , Fan, L. F. . High-ductile engineered geopolymer composites (EGC) prepared by calcined natural clay [J]. | JOURNAL OF BUILDING ENGINEERING , 2023 , 63 . |
| MLA | Zhong, W. L. et al. "High-ductile engineered geopolymer composites (EGC) prepared by calcined natural clay" . | JOURNAL OF BUILDING ENGINEERING 63 (2023) . |
| APA | Zhong, W. L. , Zhang, Y. H. , Fan, L. F. . High-ductile engineered geopolymer composites (EGC) prepared by calcined natural clay . | JOURNAL OF BUILDING ENGINEERING , 2023 , 63 . |
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Abstract ：
In rock engineering, the weakening effects of water on the stressed rock are nonnegligible. This paper studied the microstructure deterioration processes of sandstones under stress and stress-water coupling by real-time computed tomography (CT) technology and compared the difference in these two processes. Firstly, the real-time CT tests were performed on the dry and saturated sandstones during the uniaxial compression to study the progressive deterioration of sandstones caused by stress and stress-water coupling, which were further quantitatively described by porosity. Then, the equivalent radius was introduced to analyze the real-time pore structure characteristics of sandstones under stress and stress-water coupling. Finally, the difference in failure patterns of sandstones under stress and stress-water coupling was compared. The results show that the real-time CT images intuitively present the continuous changes of spatial morphology of defects in sandstones under stress and stress-water coupling. During the uniaxial compression, the porosities of dry and saturated sandstones decrease at first, then increase slowly and finally increase rapidly. However, as the increase of stress, the variation in porosity, shifting of pore size distribution curve and change of maximum equivalent radius interval of saturated sandstone are more significant, indicating that even under the same stress state, the water aggravates the microstructure deterioration of sandstone, thus leading to the reduction of bearing capacity of sandstone. In addition, the failed region of saturated sandstone is mainly composed of multiple shear and tensile cracks, which presents the typical tensile-shear composite failure.
Keyword ：
Pore structure characteristic Pore structure characteristic Failure characteristic Failure characteristic Damage-failure process Damage-failure process Microscopic observation Microscopic observation Real-time CT scanning Real-time CT scanning
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| GB/T 7714 | Fan, L. F. , Qiu, B. , Fan, Y. D. et al. Stress-Water Coupling Effects on Failure of Sandstone Based on Real-Time CT Technology [J]. | ROCK MECHANICS AND ROCK ENGINEERING , 2023 , 56 (6) : 4329-4341 . |
| MLA | Fan, L. F. et al. "Stress-Water Coupling Effects on Failure of Sandstone Based on Real-Time CT Technology" . | ROCK MECHANICS AND ROCK ENGINEERING 56 . 6 (2023) : 4329-4341 . |
| APA | Fan, L. F. , Qiu, B. , Fan, Y. D. , Gao, J. W. . Stress-Water Coupling Effects on Failure of Sandstone Based on Real-Time CT Technology . | ROCK MECHANICS AND ROCK ENGINEERING , 2023 , 56 (6) , 4329-4341 . |
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Abstract ：
A combined-wave method which can significantly reduce the length of the rock bar was proposed for investigating the stress wave propagation through micro-defected rock mass. A series of short-bar pendulum impact tests were carried out to obtain the combined waves. Subsequently, wave propagation coefficients (e.g. the attenuation coefficient and wave number) were derived based on the present combined-wave method. Finally, the present combined-wave method was validated using the traditional separated-wave method based on a series of long-bar pendulum impact tests. The results show that the wave propagation coefficients obtained by the present combined-wave method using a 0.6 m bar agree well with those obtained by the traditional separated-wave method using a 1.2 m bar. The present combined-wave method overcomes the disadvantage of the traditional separated-wave method, which requires a long bar to prevent wave superposition. A series of short-bar pendulum impact tests were conducted.A combined-wave method based on short-bar pendulum impact tests was proposed.The present combined-wave method was validated.Wave propagation coefficient can be determined by the present method efficiently.
Keyword ：
Wave number Wave number Combined-wave method Combined-wave method Attenuation coefficient Attenuation coefficient Stress wave propagation Stress wave propagation
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| GB/T 7714 | Fan, L. F. , Yang, Q. H. , Wang, M. et al. A Short-Bar Combined-Wave Method for Wave Propagation Coefficient Determination [J]. | ROCK MECHANICS AND ROCK ENGINEERING , 2023 , 57 (3) : 1815-1823 . |
| MLA | Fan, L. F. et al. "A Short-Bar Combined-Wave Method for Wave Propagation Coefficient Determination" . | ROCK MECHANICS AND ROCK ENGINEERING 57 . 3 (2023) : 1815-1823 . |
| APA | Fan, L. F. , Yang, Q. H. , Wang, M. , Du, X. L. . A Short-Bar Combined-Wave Method for Wave Propagation Coefficient Determination . | ROCK MECHANICS AND ROCK ENGINEERING , 2023 , 57 (3) , 1815-1823 . |
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Abstract ：
This study aims to prepare cement mortar with different proportions of artificial geopolymer sand (AGS) and investigate its dynamic mechanical properties. Firstly, AGS was used to replace natural sand (NS) to obtain cement mortar with different proportions of AGS (0.0%, 20.0%, 40.0%, 60.0%, 80.0% and 100.0%). Secondly, the dynamic impact test was conducted on cement mortar. The dynamic stress-strain relationship was obtained. Finally, the effects of AGS replacement rate and strain rate on dynamic mechanical properties (dynamic strength, elastic modulus, energy absorption and dynamic increase factor DIF) of cement mortar were discussed. The results show that the dynamic strength, elastic modulus and energy absorption of cement mortar increase firstly and then decrease as replacement rate increases at a fixed impact pressure, while DIF decreases firstly and then increases with replacement rate increasing. The dynamic strength, elastic modulus and energy absorption reach the maximum, the DIF reaches the minimum at the replacement rate of 20.0%. In addition, the dynamic strength, DIF and energy absorption of cement mortar significantly increase as strain rate increases, showing an obvious rate dependence.
Keyword ：
Cement mortar Cement mortar Dynamic mechanical properties Dynamic mechanical properties Replacement rate Replacement rate Artificial geopolymer sand Artificial geopolymer sand
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| GB/T 7714 | Gao, J. W. , Li, H. , Zhong, W. L. et al. Effects of artificial geopolymer sand as an alternative to natural sand on dynamic mechanical properties of cement mortar [J]. | CONSTRUCTION AND BUILDING MATERIALS , 2023 , 394 . |
| MLA | Gao, J. W. et al. "Effects of artificial geopolymer sand as an alternative to natural sand on dynamic mechanical properties of cement mortar" . | CONSTRUCTION AND BUILDING MATERIALS 394 (2023) . |
| APA | Gao, J. W. , Li, H. , Zhong, W. L. , Fan, L. F. , Jiang, D. . Effects of artificial geopolymer sand as an alternative to natural sand on dynamic mechanical properties of cement mortar . | CONSTRUCTION AND BUILDING MATERIALS , 2023 , 394 . |
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Abstract ：
The effective velocity of the reflected wave in rock mass is of significance to the detection of crustal structure and the geophysical seismic exploration. In this paper, the modified characteristic method was introduced to solve P-wave reflection in rock mass with different wave impedances on two sides of the joint. Effective velocity was defined to characterize the propagation velocity of the reflected wave in jointed rock mass. The effects of incident frequency, joint stiffness and wave impedance ratio on the effective velocity were discussed. The results show that when the stress wave propagation in "hard-to-soft" rock mass, the effective velocity increases firstly and then decreases as the incident frequency and the joint stiffness increase, while the effective velocity always decreases as the wave impedance ratio increases; when the stress wave propagation in "soft-to-hard" rock mass, the effective velocity decreases as the incident frequency increases, increases as the joint stiffness increases and decreases as the wave impedance ratio increases. The wave impedance ratio has an important influence on the effective velocity. The effective velocity without considering wave impedance ratio is smaller than that of stress wave propagation in "soft-to-hard" rock mass, but larger than that of stress wave propagation in "hard-to-soft" rock mass.
Keyword ：
linear deformation linear deformation reflected wave reflected wave effective velocity effective velocity wave impedance ratio wave impedance ratio rock joint rock joint
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| GB/T 7714 | Wang, Lijuan , Wu, Chengqing , Fan, Lifeng et al. Effective velocity of reflected wave in rock mass with different wave impedances of normal incidence of stress wave [J]. | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS , 2022 , 46 (9) : 1607-1619 . |
| MLA | Wang, Lijuan et al. "Effective velocity of reflected wave in rock mass with different wave impedances of normal incidence of stress wave" . | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS 46 . 9 (2022) : 1607-1619 . |
| APA | Wang, Lijuan , Wu, Chengqing , Fan, Lifeng , Wang, Meng . Effective velocity of reflected wave in rock mass with different wave impedances of normal incidence of stress wave . | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS , 2022 , 46 (9) , 1607-1619 . |
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